MASSMUTUAL FUNDS

This Prospectus describes the following Funds:

Fund Name			Class I
MM Equity Asset Fund			MSEJX
MassMutual Select T. Rowe Price Bond Asset Fund			MMBEX
MassMutual Select T. Rowe Price Emerging Markets Bond Fund			MMEMX
MassMutual Select T. Rowe Price Large Cap Blend Fund			MMLRX
MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund			MMLDX
MassMutual Select T. Rowe Price Real Assets Fund			MMRFX
MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund			MMBUX
MassMutual Select T. Rowe Price U.S. Treasury Long-Term Index Fund			MMUTX

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the adequacy of this Prospectus. Any statement to the contrary is a crime.

PROSPECTUS

February 1, 2024

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Table Of Contents

	Page
About the Funds
MM Equity Asset Fund		3
MassMutual Select T. Rowe Price Bond Asset Fund		7
MassMutual Select T. Rowe Price Emerging Markets Bond Fund		15
MassMutual Select T. Rowe Price Large Cap Blend Fund		21
MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund		27
MassMutual Select T. Rowe Price Real Assets Fund		33
MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund		39
MassMutual Select T. Rowe Price U.S. Treasury Long-Term Index Fund		45
Additional Information Regarding Investment Objectives and Principal Investment Strategies		50
Disclosure of Portfolio Holdings		52
Additional Information Regarding Principal Risks		52
Management of the Funds
Investment Adviser		72
Subadvisers and Portfolio Managers		72
About the Class of Shares – I Shares		76
Buying, Redeeming, and Exchanging Shares		76
Frequent Trading Policies		79
Determining Net Asset Value		80
Taxation and Distributions		81
Financial Highlights		84
Index Descriptions		92

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MM Equity Asset Fund

INVESTMENT OBJECTIVE

The Fund seeks to provide a consistently high total return from a broadly diversified portfolio of equity securities with risk characteristics similar to the Standard and Poor’s 500 Composite Stock Price Index (S&P 500® Index*).

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.18%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.10%
Total Annual Fund Operating Expenses			0.28%

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in each share class of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment earns a 5% return each year and that the Fund’s operating expenses are exactly as described in the preceding table. Although your actual costs may

be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$29			$90			$157			$356

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27% of the average value of its portfolio.

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities. Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stocks, rights, and warrants. The Fund typically invests most of its assets in the common stocks of U.S. companies in the S&P 500 Index (the “Index”). The Fund may also invest in securities not included within the Index. As of December 31, 2023, the market capitalization range of companies included in the Index was $6.50 billion to $2.99 trillion. Sector by sector, the Fund’s weightings are similar to those of the Index. Within each sector, the Fund’s subadviser, J.P. Morgan Investment Management Inc. (“J.P. Morgan”), modestly overweights equity securities that it considers undervalued or fairly valued while modestly underweighting or not holding equity securities that appear overvalued. By owning a large number of equity securities within the Index, with an emphasis on those that appear undervalued or fairly valued, the Fund seeks returns that modestly exceed those of the Index over the long term with a modest level of volatility as compared to the Index.

The Fund may use derivatives as substitutes for securities in which the Fund can invest. To the extent the Fund uses derivatives, the Fund will primarily use futures contracts to more effectively gain targeted equity exposure from its cash

The “S&P 500 Index” is a product of S&P Dow Jones Indices LLC or its affiliates (“SPDJI”), and has been licensed for use by MassMutual. S&P®, S&P 500®, US 500, The 500, iBoxx®, iTraxx® and CDX® are trademarks of S&P Global, Inc. or its affiliates (“S&P”); Dow Jones® is a registered trademark of Dow Jones Trademark Holdings LLC (“Dow Jones”); and these trademarks have been licensed for use by SPDJI and sublicensed for certain purposes by MassMutual. The Fund is not sponsored, endorsed, sold or promoted by SPDJI, Dow Jones, S&P, or their respective affiliates, and none of such parties make any representation regarding the advisability of investing in such product(s) nor do they have any liability for any errors, omissions, or interruptions of the S&P 500 Index.

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positions. Use of derivatives by the Fund may create investment leverage.

In managing the investments of the Fund, J.P. Morgan employs a three-step process that combines research, valuation, and stock selection. J.P. Morgan takes an in-depth look at company prospects over a period as long as five years, which is designed to provide insight into a company’s real growth potential. The research findings allow J.P. Morgan to rank the companies in each sector group according to their relative values. As a part of its investment process, J.P. Morgan seeks to assess the impact of environmental, social, and governance factors (including accounting and tax policies, disclosure and investor communication, shareholder rights, and remuneration policies) on the cash flows of many companies in which it may invest to identify issuers that J.P. Morgan believes will be negatively impacted by such factors relative to other issuers. These determinations may not be conclusive and securities of such issuers may be purchased and retained by the Fund.

J.P. Morgan buys and sells equity securities, using the research and valuation rankings as a basis. Along with attractive valuation, J.P. Morgan often considers a number of other criteria:

•

catalysts that could trigger a rise in a stock’s price;

•

impact on the overall risk of the portfolio relative to the Index;

•

high perceived potential reward compared to perceived potential risk; and

•

possible temporary mispricings caused by apparent market overreactions.

J.P. Morgan may sell a security as its valuation or ranking changes or if more attractive investments become available.

Principal Risks

The following are the Principal Risks of the Fund. The value of your investment in the Fund could go down as well as up. You can lose money by investing in the Fund. Certain risks relating to instruments and strategies used in the management of the Fund are placed first. The significance of any specific risk to an investment in the Fund will vary over time, depending on the composition of the Fund’s portfolio, market conditions, and other factors. You should read all of the risk information presented below carefully, because any one or more of these risks may result in losses to the Fund.

Equity Securities Risk Although stocks may have the potential to outperform other asset classes

over the long term, their prices tend to fluctuate more dramatically over the shorter term. These movements may result from factors affecting individual companies, or from broader influences like changes in interest rates, market conditions, or investor confidence, or announcements of economic, political, or financial information.

Derivatives Risk Derivatives can be highly volatile and involve risks different from, and potentially greater than, direct investments, including risks of imperfect correlation between the value of derivatives and underlying assets, counterparty default, potential losses that partially or completely offset gains, and illiquidity. Derivatives can create investment leverage. Losses from derivatives can be substantially greater than the derivatives’ original cost and can sometimes be unlimited. If the value of a derivative does not correlate well with the particular market or asset class the derivative is designed to provide exposure to, the derivative may not have the effect or benefit anticipated. Derivatives can also reduce the opportunity for gains or result in losses by offsetting positive returns in other investments. Many derivatives are traded in the over-the-counter market and not on exchanges.

Growth Company Risk The prices of growth securities are often highly sensitive to market fluctuations because of their heavy dependence on future earnings or cash flow expectations, and can be more volatile than the market in general.

Indexing Risk The Fund’s performance may not track the performance of the index due to a number of factors, including fees and expenses of the Fund, the Fund’s cash positions, and differences between securities held by the Fund and the securities comprising the index which may result from legal restrictions, costs, or liquidity constraints, especially during times when a sampling methodology is used.

Large Company Risk Large-capitalization stocks as a group could fall out of favor with the market, causing the Fund’s investments in large-capitalization stocks to underperform investments that focus on small- or medium-capitalization stocks. Larger, more established companies may be slow to respond to challenges and may grow more slowly than smaller companies.

Small and Mid-Cap Company Risk Market risk and liquidity risk are particularly pronounced for securities of small and medium-sized companies, which may trade less frequently and in smaller

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volumes than more widely-held securities, and may fluctuate in price more than other securities. Their shares can be less liquid than those of larger companies, especially during market declines. Small and medium-sized companies may have limited product lines, markets, or financial resources and may be dependent on a limited management group; they may have been recently organized and have little or no track record of success.

Value Company Risk The value investment approach entails the risk that the market will not recognize a security’s intrinsic value for a long time, or that a stock the investment adviser or subadviser judges to be undervalued may actually be appropriately priced.

Cash Position Risk If the Fund holds a significant portion of its assets in cash or cash equivalents, its investment returns may be adversely affected and the Fund may not achieve its investment objective.

Liquidity Risk Certain securities may be difficult (or impossible) to sell or certain positions may be difficult to close out at a desirable time and price, and the Fund may be required to hold an illiquid investment that is declining in value, or it may be required to sell certain illiquid investments at a price or time that is not advantageous in order to meet redemptions or other cash needs. Some securities may be subject to restrictions on resale. There can be no assurance that there will be a liquid market for instruments held by the Fund at any time. The Fund may not receive the proceeds from the sale of certain investments for an extended period.

Management and Operational Risk The Fund relies on the manager’s investment analysis and its selection of investments to achieve its investment objective, and the Fund is subject to the risk that the manager’s assessment of an investment is wrong. There can be no assurance that the Fund will achieve the intended results and the Fund may incur significant losses. The Fund also runs the risk that deficiencies in the investment adviser’s, subadviser’s, or another service provider’s internal systems or controls will cause losses for the Fund or impair Fund operations.

economic, industry, political, regulatory, geopolitical, public health, and other conditions, as well as investor perceptions of these conditions. The Fund is subject to risks affecting issuers, such as management performance, financial leverage, industry problems, and reduced demand for goods or services.

Sector Risk The Fund may allocate more of its assets to particular industries or to particular economic, market, or industry sectors than to others. This could increase the volatility of the Fund’s portfolio, and the Fund’s performance may be more susceptible to developments affecting issuers in those industries or sectors than if the Fund invested more broadly.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

Annual Performance

Class I Shares

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Highest
Quarter:

2Q ’20,

21.97%

Lowest
Quarter:

1Q ’20,

–19.51%

After-tax returns are calculated using the historical highest individual U.S. federal marginal income tax rates and do not reflect the impact of state and local taxes. Actual after-tax returns depend on an investor’s tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold Fund shares through tax-advantaged arrangements, such as 401(k) plans or individual retirement accounts.

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Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (09/15/16)
Class I	Return Before Taxes		28.23	%		16.81	%		13.20	%
	Return After Taxes on Distributions		24.42	%		13.18	%		8.97	%
	Return After Taxes on Distributions and Sales of Fund Shares		19.36	%		13.08	%		9.58	%
S&P 500 Index (reflects no deduction for fees, expenses, or taxes)			26.29	%		15.69	%		13.75	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): J.P. Morgan Investment Management Inc. (“J.P. Morgan”)

Portfolio Manager(s):

Tim Snyder, CFA, CMT is an Executive Director and a portfolio manager at J.P. Morgan. He has managed the Fund since September 2018.

Raffaele Zingone, CFA is a Managing Director and a portfolio manager at J.P. Morgan. He has managed the Fund since September 2018.

PURCHASE AND SALE OF FUND SHARES

Currently, shares of the Fund are only available to other MassMutual Funds, although, at the discretion of the Trust, shares of the Fund may be offered to a broader range of investors at any time. Fund shares are redeemable on any business day by written request.

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price Bond Asset Fund

INVESTMENT OBJECTIVE

The Fund seeks a regular level of income consistent with the preservation of capital over time.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.11%
Total Annual Fund Operating Expenses			0.11%
Expense Reimbursement			(0.11%)
Total Annual Fund Operating Expenses after Expense Reimbursement(1)			0.00%

(1)

The expenses in the above table reflect a written agreement by MML Advisers to cap the fees and expenses of the Fund (other than extraordinary legal and other expenses, Acquired Fund Fees and Expenses, interest expense, expenses related to borrowings, securities lending, leverage, taxes, and brokerage, short sale dividend and loan expense, or other non-recurring or unusual expenses such as organizational expenses and shareholder meeting expenses, as applicable) through January 31, 2025, to the extent that Total Annual Fund Operating Expenses after Expense Reimbursement would otherwise exceed 0.00% for Class I. The Total Annual Fund Operating Expenses after Expense Reimbursement shown in the above table may exceed these amounts, because, as noted in the previous sentence, certain fees and expenses are excluded from the cap. The agreement can only be terminated by mutual consent of the Board of Trustees on behalf of the Fund and MML Advisers.

Example

preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$0			$24			$51			$130

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in bonds. The Fund’s investments may include, but are not limited to, obligations issued by U.S. and foreign governments and their agencies, bonds issued by U.S. and foreign corporations, U.S. and non-U.S. dollar denominated foreign securities (including securities of emerging market issuers), mortgage- and asset-backed securities, Treasury inflation protected securities, and bank loans (which represent interests in amounts loaned to companies by banks and other lenders). Debt securities in which the Fund invests may pay interest at fixed, variable, or floating rates. The Fund may purchase and sell securities (including mortgage-backed securities) on a when-issued, delayed delivery, to-be-announced (“TBA”), or forward commitment basis, and may enter into dollar roll transactions. These may include so-called “short” TBA transactions, where the Fund attempts to hedge existing exposures or to increase its return by selling forward mortgages or mortgage-related assets it owns.

The Fund may invest up to 30% of its total assets in below investment grade debt securities (“junk” or “high yield” bonds), including securities in default. These “junk” or “high yield” bonds include those that are at the time of investment rated BB+ or equivalent, or lower by each of the rating

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agencies that has assigned a rating to the bond or are unrated and considered by the Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”), to be of comparable quality. In the event that a security is downgraded after its purchase by the Fund, the Fund may continue to hold the security if T. Rowe Price considers that doing so would be consistent with the Fund’s investment objective. If a bond is split-rated (i.e., assigned different ratings by different credit ratings agencies), the higher rating will be used.

The Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, for hedging purposes, to adjust various portfolio characteristics, including the duration (interest rate volatility) of the Fund’s portfolio, or as a substitute for direct investments in securities. Such derivatives may include futures contracts, interest rate swaps, total return swaps, credit default swaps, and options. The Fund may also, but will not necessarily, engage in foreign currency transactions, including forward contracts, options on currencies, futures contracts, and swap contracts, to seek to hedge or to attempt to protect against adverse changes in currency exchange rates or otherwise to adjust the currency exposures within the Fund’s portfolio. Use of derivatives by the Fund may create investment leverage. The Fund may hold a portion of its assets in cash or cash equivalents.

T. Rowe Price has the flexibility to invest the Fund’s assets across the global fixed income universe without constraints tied to particular benchmarks or asset classes in an effort to create a portfolio with low overall volatility and consistent income even in a rising interest rate environment. T. Rowe Price expects that the Fund will normally maintain a relatively concentrated portfolio.

T. Rowe Price has considerable flexibility in seeking income on behalf of the Fund and may invest in bonds with varying maturities. Because the Fund does not have any maturity restrictions, T. Rowe Price can purchase long-term bonds, which tend to have higher yields than shorter-term bonds. The maturities of the Fund’s holdings generally reflect T. Rowe Price’s outlook for interest rates. In addition, when there is a large yield difference between securities of various quality levels, T. Rowe Price may choose to move down the credit scale and purchase lower-rated bonds with higher yields. When the difference is small or the outlook warrants, T. Rowe Price may choose to concentrate investments in higher-rated issues. When deciding whether to adjust duration (which means the

Fund’s price sensitivity to interest rate changes) or allocations among the various sectors and asset classes, T. Rowe Price weighs such factors as expected interest rate movements and currency valuations, the outlook for inflation and the economy, and the yield advantage that lower rated bonds may offer over investment-grade bonds.

T. Rowe Price may sell assets for a variety of reasons, including in response to a change in the original investment considerations or to limit losses, adjust the characteristics of the overall portfolio, or redeploy assets into different opportunities.

The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Principal Risks

The following are the Principal Risks of the Fund. The value of your investment in the Fund could go down as well as up. You can lose money by investing in the Fund. References in this section to the Fund’s subadviser may include any sub-subadvisers as applicable. Certain risks relating to instruments and strategies used in the management of the Fund are placed first. The significance of any specific risk to an investment in the Fund will vary over time, depending on the composition of the Fund’s portfolio, market conditions, and other factors. You should read all of the risk information presented below carefully, because any one or more of these risks may result in losses to the Fund.

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that the value of a fixed income security will fall when interest rates rise), extension risk (the risk that the average life of a security will be extended through a slowing of principal payments), prepayment risk (the risk that a security will be prepaid and the Fund will be required to reinvest at a less favorable rate), duration risk (the risk that longer-term securities may be more sensitive to interest rate changes), inflation risk (the risk that as inflation increases, the present value of the Fund’s fixed income investment typically will decline), and credit risk.

Bank Loans Risk Many of the risks associated with bank loans are similar to the risks of investing in below investment grade debt securities. Changes in the financial condition of the borrower or economic conditions or other circumstances may reduce the capacity of the borrower to make principal and interest payments on such instruments and may lead to defaults. Senior secured bank loans are typically supported by collateral; however the value of the collateral may be insufficient to cover the amount owed to the Fund, or the Fund may be prevented or delayed from realizing on the collateral. Some loans may be unsecured; unsecured loans generally present a greater risk of loss to the Fund if the issuer defaults. If the Fund relies on a third party to administer a loan, the Fund is subject to the risk that the third party will fail to perform its obligations. In addition, if the Fund holds only a participation interest in a loan made by a third party, the Fund’s receipt of payments on the loan will depend on the third party’s willingness and ability to make those payments to the Fund. The settlement time for certain loans is longer than the settlement time for many other types of investments, and the Fund may not receive the payment for a loan sold by it until well after the sale; that cash would be unavailable for payment of redemption proceeds or for reinvestment. Interests in some bank loans may not be readily marketable and may be subject to restrictions on resale. In some cases, negotiations involved in disposing of indebtedness may require weeks to complete. Consequently, some indebtedness may be difficult or impossible to dispose of readily at what the Fund believes to be a fair price. Some loans may not be considered “securities” for certain purposes under the federal securities laws, and purchasers, such as the Fund, therefore may not be entitled to rely on the anti-fraud protections of the federal securities laws.

Below Investment Grade Debt Securities Risk Below investment grade debt securities, commonly known

as “junk” or “high yield” bonds, have speculative characteristics and involve greater volatility of price and yield, greater risk of loss of principal and interest, and generally reflect a greater possibility of an adverse change in financial condition that could affect an issuer’s ability to honor its obligations.

Credit Risk Credit risk is the risk that an issuer, guarantor, or liquidity provider of a fixed income security held by the Fund may be unable or unwilling, or may be perceived (whether by market participants, ratings agencies, pricing services or otherwise) as unable or unwilling, to make timely principal and/or interest payments, or to otherwise honor its obligations. The Fund may also be exposed to the credit risk of its counterparty to repurchase agreements, reverse repurchase agreements, swap transactions, and other derivatives transactions, and to the counterparty’s ability or willingness to perform in accordance with the terms of the transaction. The value of such transactions to the Fund will depend on the willingness and ability of the counterparty to perform its obligations, including among other things the obligation to return collateral or margin to the Fund. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances.

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Foreign Investment Risk; Emerging Markets Risk; Currency Risk Investments in securities of foreign issuers, securities of companies with significant foreign exposure, and foreign currencies can involve additional risks relating to market, industry, political, regulatory, public health, and other conditions. Political, social, diplomatic, and economic developments, U.S. and foreign government action, or threat thereof, such as the imposition of currency or capital blockages, controls, or tariffs, economic and trade sanctions or embargoes, security trading suspensions, entering or exiting trade or other intergovernmental agreements, or the expropriation or nationalization of assets in a particular country, can cause dramatic declines in certain or all securities with exposure to that country and other countries. Sanctions, or the threat of sanctions, may cause volatility in regional and global markets and may negatively impact the performance of various sectors and industries, as well as companies in other countries, which could have a negative effect on the performance of the Fund. In the event of nationalization, expropriation, confiscation, or other government action, intervention, or restriction, the Fund could lose its entire investment in a particular foreign issuer or country. There may be quotas or other limits on the ability of the Fund (or clients of the Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries. Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. Emerging markets securities are subject to greater risks than

securities issued in developed foreign markets, including less liquidity, less stringent investor protection and disclosure standards, less reliable settlement practices, greater price volatility, higher relative rates of inflation, greater political, economic, and social instability, greater custody and operational risks, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater volatility in currency exchange rates, and are more susceptible to environmental problems. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and settlement practices, and lower trading volumes that could lead to greater price volatility and illiquidity. Non-U.S. transaction costs, such as brokerage commissions and custody costs, may be higher than in the United States. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

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the servicing of mortgage loans secured by real estate properties. During periods of difficult economic conditions, delinquencies and losses on commercial mortgage-backed investments in particular generally increase, including as a result of the effects of those conditions on commercial real estate markets, the ability of commercial tenants to make loan payments, and the ability of a property to attract and retain commercial tenants. Investments that receive only the interest portion or the principal portion of payments on the underlying assets may be highly volatile. Litigation with respect to the representations and warranties given in connection with the issuance of mortgage-backed securities can be an important consideration in investing in such securities, and the outcome of any such litigation could significantly impact the value of the Fund’s mortgage-backed investments.

Defaulted and Distressed Securities Risk Because the issuer of such securities is in default and is likely to be in distressed financial condition, repayment of defaulted securities and obligations of distressed issuers (including insolvent issuers or issuers in payment or covenant default, in workout or restructuring, or in bankruptcy or insolvency proceedings) is uncertain. To the extent the Fund is invested in distressed securities, its ability to achieve current income for its shareholders may be diminished.

Dollar Roll Transaction Risk Dollar roll transactions generally create leverage and subject the Fund to the credit risk of the counterparty.

Frequent Trading/Portfolio Turnover Risk Portfolio turnover generally involves some expense to the Fund and may result in the realization of taxable capital gains (including short-term gains). The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance.

Geographic Focus Risk When the Fund focuses investments on a particular country, group of countries, or geographic region, its performance will be closely tied to the market, currency, economic, political, or regulatory conditions and developments in those countries or that region, and could be more volatile than the performance of more geographically diversified funds.

Hedging Risk The Fund’s attempts at hedging and taking long and short positions in currencies may not be successful and could cause the Fund to lose money or fail to get the benefit of a gain on a hedged position. If expected changes to securities prices, interest rates, currency values, and exchange rates, or the creditworthiness of an issuer are not accurately predicted, the Fund could be in a worse position than if it had not entered into such transactions.

Inflation Risk The value of assets or income from the Fund’s investments will be less in the future as inflation decreases the value of money. As inflation increases, the value of the Fund’s assets can decline as can the value of the Fund’s distributions. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy (or expectations that such policies will change), and the Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors.

Leveraging Risk Instruments and transactions, including derivatives transactions, that create leverage may cause the value of an investment in the Fund to be more volatile, could result in larger losses than if they were not used, and tend to compound the effects of other risks.

LIBOR Transition and Other Reference Benchmarks Risk The London Interbank Offered Rate (“LIBOR”) was the offered rate for short-term Eurodollar deposits between major international banks. The terms of investments, financings, or other transactions (including certain derivatives transactions) to which the Fund may be a party have historically been tied to LIBOR. In connection with the global transition away from LIBOR led by regulators and market participants, LIBOR was last published on a representative basis at the end of June 2023. Alternative reference rates to LIBOR have been established in most major currencies and the transition to new reference rates continues. Markets in these new rates are developing, but questions around liquidity and how to appropriately mitigate any economic value transfer as a result of the transition remain a concern. The transition away from LIBOR and the use of replacement rates may adversely affect transactions that used LIBOR as a reference rate, financial institutions, funds, and other market participants that engaged in such transactions, and the financial markets generally. The impact of the transition away from LIBOR on the Fund or

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the financial instruments in which the Fund invests cannot yet be fully determined. In addition, interest rates or other types of rates and indexes which are classed as “benchmarks” have been the subject of ongoing national and international regulatory reform, including under the European Union regulation on indexes used as benchmarks in financial instruments and financial contracts (known as the “Benchmarks Regulation”). The Benchmarks Regulation has been enacted into United Kingdom law by virtue of the European Union (Withdrawal) Act 2018 (as amended), subject to amendments made by the Benchmarks (Amendment and Transitional Provision) (EU Exit) Regulations 2019 (SI 2019/657) and other statutory instruments. Following the implementation of these reforms, the manner of administration of benchmarks has changed and may further change in the future, with the result that relevant benchmarks may perform differently than in the past, the use of benchmarks that are not compliant with the new standards set by certain supervised entities may be restricted, and certain benchmarks may be eliminated entirely. Additionally, there could be other consequences which cannot be predicted.

Market Risk The value of the Fund’s portfolio securities may decline, at times sharply and

unpredictably, as a result of unfavorable market-induced changes affecting particular industries, sectors, or issuers. Stock and bond markets can decline significantly in response to issuer, market, economic, industry, political, regulatory, geopolitical, public health, and other conditions, as well as investor perceptions of these conditions. The Fund is subject to risks affecting issuers, such as management performance, financial leverage, industry problems, and reduced demand for goods or services.

Reinvestment Risk Income from the Fund’s portfolio will decline if and when the Fund invests the proceeds from matured, traded, or called debt obligations at market interest rates that are below the portfolio’s current earnings rate. A decline in income could affect the Fund’s overall return.

Short Sales Risk If the Fund sells a security short, it will make money if the security’s price goes down (in an amount greater than any transaction costs) and will lose money if the security’s price goes up. There is no limit on the amount of money the Fund may lose on a short sale. The Fund may not be able to close out a short sale when it might wish to do so, or may only do so at an unfavorable price. Short sales can involve leverage. If the Fund invests the proceeds from short positions in other securities the Fund could lose money both on the short positions and on the securities in which it has invested the short proceeds.

Sovereign Debt Obligations Risk Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. Many sovereign debt obligations may be rated below investment grade (“junk” or “high yield” bonds). Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation. In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt.

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U.S. Government Securities Risk Obligations of certain U.S. Government agencies and instrumentalities are not backed by the full faith and credit of the U.S. Government, and there can be no assurance that the U.S. Government would provide financial support to such agencies and instrumentalities.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

When-Issued, Delayed Delivery, TBA, and Forward Commitment Transaction Risk These transactions may create leverage and involve a risk of loss if the value of the securities declines prior to settlement.

Performance Information

Annual Performance

Class I Shares

[MISSING IMAGE: ampibl6p7crjffu1ai4cvp5knsai.jpg]

Highest
Quarter:

4Q ’23,

6.46%

Lowest
Quarter:

2Q ’22,

–5.73%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		6.59	%		1.25	%		1.16	%
	Return After Taxes on Distributions		5.63	%		-0.19	%		-0.30	%
	Return After Taxes on Distributions and Sales of Fund Shares		3.89	%		0.41	%		0.32	%
Bloomberg U.S. Aggregate Bond Index (reflects no deduction for fees, expenses, or taxes)			5.53	%		1.10	%		1.28	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

Sub-subadviser(s): T. Rowe Price International Ltd (“T. Rowe Price International”)

T. Rowe Price Hong Kong Limited (“T. Rowe Price Hong Kong”)

Portfolio Manager(s):

Steve Bartolini, CFA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since its inception (February 2018).

Andrew J. Keirle is a Vice President at and Portfolio Manager at T. Rowe Price International. He has managed the Fund since February 2023.

Ken Orchard, CFA is a Vice President and Portfolio Manager at T. Rowe Price International. He has managed the Fund since its inception (February 2018).

Saurabh Sud, CFA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since May 2023.

PURCHASE AND SALE OF FUND SHARES

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TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price Emerging Markets Bond Fund

INVESTMENT OBJECTIVE

The Fund seeks to provide high income and capital appreciation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.25%
Total Annual Fund Operating Expenses			0.25%
Expense Reimbursement			(0.25%)
Total Annual Fund Operating Expenses after Expense Reimbursement(1)			0.00%

(1)

Example

preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$0			$55			$115			$293

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in debt securities of emerging market governments or companies located in emerging market countries (including so-called “frontier markets”). The Fund’s investments in debt securities typically consist of corporate and sovereign bonds. Debt securities in which the Fund invests may pay interest at fixed, variable, or floating rates. The Fund relies on a classification by either J.P. Morgan or the International Monetary Fund to determine which countries are considered emerging markets. The Fund may invest in securities denominated in U.S.-dollar or foreign currencies, including emerging market currencies. The Fund normally will invest in at least three countries.

The Fund may invest in debt securities of any credit quality and may invest without limit in below investment grade debt securities (“junk” or “high yield” bonds), including securities in default. These “junk” or “high yield” bonds include those that are at the time of investment rated BB+ or lower by S&P or Ba1 or lower by Moody’s or the equivalent by any other nationally recognized statistical rating organization or are unrated and considered by the Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”), to be of comparable quality. Although the Fund expects to maintain an intermediate- to long-term weighted

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average maturity, there are no maturity restrictions on the overall portfolio or on individual securities.

In selecting securities, T. Rowe Price relies heavily on research, which analyzes political and economic trends as well as creditworthiness of particular issuers. T. Rowe Price tends to favor bonds it expects will be upgraded. T. Rowe Price may sell assets for a variety of reasons, including in response to a change in the original investment considerations or to limit losses, adjust the characteristics of the overall portfolio, or redeploy assets into different opportunities.

Principal Risks

security or issuer or fixed income securities generally. Certain events, such as market or economic developments, regulatory or government actions, natural disasters, pandemics, terrorist attacks, war, and other geopolitical events can have a dramatic adverse effect on the debt market and the overall liquidity of the market for fixed income securities. During those periods, the Fund may experience high levels of shareholder redemptions, and may have to sell securities at times when the Fund would otherwise not do so, and potentially at unfavorable prices. Certain securities may be difficult to value during such periods. Fixed income securities are subject to interest rate risk (the risk that the value of a fixed income security will fall when interest rates rise), extension risk (the risk that the average life of a security will be extended through a slowing of principal payments), prepayment risk (the risk that a security will be prepaid and the Fund will be required to reinvest at a less favorable rate), duration risk (the risk that longer-term securities may be more sensitive to interest rate changes), inflation risk (the risk that as inflation increases, the present value of the Fund’s fixed income investment typically will decline), and credit risk.

Below Investment Grade Debt Securities Risk Below investment grade debt securities, commonly known as “junk” or “high yield” bonds, have speculative characteristics and involve greater volatility of price and yield, greater risk of loss of principal and interest, and generally reflect a greater possibility of an adverse change in financial condition that could affect an issuer’s ability to honor its obligations.

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or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances.

There may be quotas or other limits on the ability of the Fund (or clients of the Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries. Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. Emerging markets securities are subject to greater risks than securities issued in developed foreign markets, including less liquidity, less stringent investor protection and disclosure standards, less reliable settlement practices, greater price volatility, higher relative rates of inflation, greater political, economic, and social instability, greater custody and operational risks, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater volatility in currency exchange rates, and are more susceptible to environmental problems. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and

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settlement practices, and lower trading volumes that could lead to greater price volatility and illiquidity. Non-U.S. transaction costs, such as brokerage commissions and custody costs, may be higher than in the United States. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

will change), and the Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors.

Market Risk The value of the Fund’s portfolio securities may decline, at times sharply and unpredictably, as a result of unfavorable market-induced changes affecting particular industries, sectors, or issuers. Stock and bond markets can decline significantly in response to issuer, market, economic, industry, political, regulatory, geopolitical, public health, and other conditions, as well as investor perceptions of these conditions. The Fund is subject to risks affecting issuers, such as management performance, financial leverage, industry problems, and reduced demand for goods or services.

Reinvestment Risk Income from the Fund’s portfolio will decline if and when the Fund invests the proceeds from matured, traded, or called debt obligations at market interest rates that are below

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the portfolio’s current earnings rate. A decline in income could affect the Fund’s overall return.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund’s performance from year to year for Class I shares. The table shows how the Fund’s average annual returns for 1 and 5 years, and since inception, compare with those of a broad measure of market performance and an additional index that has characteristics similar to those of the Fund (J.P. Morgan Emerging Markets Bond Index Global Diversified). Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Annual Performance

Class I Shares

[MISSING IMAGE: t1850ktk3c1lp6pk01iivmp2c7p8.jpg]

Highest
Quarter:

2Q ’20,

13.51%

Lowest
Quarter:

1Q ’20,

–16.08%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		13.50	%		2.21	%		0.84	%
	Return After Taxes on Distributions		10.75	%		-0.14	%		-1.37	%
	Return After Taxes on Distributions and Sales of Fund Shares		7.94	%		0.72	%		-0.27	%
Bloomberg Emerging Markets Hard Currency (USD) Aggregate Index (reflects no deduction for fees, expenses, or taxes)			9.63	%		1.36	%		0.79	%
J.P. Morgan Emerging Markets Bond Index Global Diversified (reflects no deduction for fees, expenses, or taxes)			11.09	%		1.67	%		1.10	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

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Sub-subadviser(s): T. Rowe Price International Ltd (“T. Rowe Price International”)

T. Rowe Price Hong Kong Limited (“T. Rowe Price Hong Kong”)

Portfolio Manager(s):

Samy Muaddi is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since June 2020.

PURCHASE AND SALE OF FUND SHARES

Currently, shares of the Fund are only available to other MassMutual Funds, although, at the discretion of the Trust, shares of the Fund may be

offered to a broader range of investors at any time. Fund shares are redeemable on any business day by written request.

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price Large Cap Blend Fund

INVESTMENT OBJECTIVE

The Fund seeks long-term capital appreciation through investments in common stock.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.03%
Total Annual Fund Operating Expenses			0.03%
Expense Reimbursement			(0.03%)
Total Annual Fund Operating Expenses after Expense Reimbursement(1)			0.00%

(1)

Example

preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$0			$7			$14			$36

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of large cap companies. The Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”), currently defines “large cap” companies as those whose market capitalizations at the time of purchase are within the market capitalization range of companies included in the S&P 500® Index or the Russell 1000® Index (as of December 31, 2023, between $270.19 million and $2.99 trillion). The Fund may invest up to 20% of its net assets in companies whose market capitalizations at the time of investment are outside of that capitalization range. Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stock, rights, warrants, and real estate investment trusts (“REITs”). The Fund typically invests most of its assets in common stocks of U.S. companies, but may invest up to 30% of its total assets in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities. The Fund may at times invest a substantial portion of its assets in obligations of issuers in one or more market, economic, or industry sectors such as information technology companies. The Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, for hedging purposes, to adjust various

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portfolio characteristics, or as a substitute for direct investments in securities. Such derivatives may include futures contracts, swaps, and options. The Fund may also, but will not necessarily, engage in foreign currency transactions, including forward contracts, options on currencies, futures contracts, and swap contracts, to seek to hedge or to attempt to protect against adverse changes in currency exchange rates or otherwise to adjust the currency exposures within the Fund’s portfolio. Use of derivatives by the Fund may create investment leverage. The Fund’s investments may include holdings in privately held companies and companies that only recently began to trade publicly. The Fund may hold a portion of its assets in cash or cash equivalents.

The Fund’s holdings will be widely diversified by industry and issuer. T. Rowe Price may employ a growth or value approach in selecting investments. For example, T. Rowe Price may seek to identify companies whose price/earnings ratios are attractive relative to the underlying earnings growth rates (e.g., emerging growth companies) and/or companies that appear to be undervalued by various measures and may be temporarily out of favor but have good prospects for capital appreciation.

T. Rowe Price generally looks for companies with one or more of the following: strong cash flow; an above-average rate of earnings growth; the ability to sustain earnings momentum during economic downturns; occupation of a lucrative niche in the economy and the ability to expand even during times of slow economic growth; low price/earnings, price/book value, price/sales, or price/cash flow ratios relative to the S&P 500 Index, a company’s peers, or a company’s own historical norm; low stock price relative to a company’s underlying asset values; companies that may benefit from restructuring activity and/or a sound balance sheet and other positive financial characteristics; and a seasoned management team with a track record of providing superior financial results.

In pursuing the Fund’s investment objective, T. Rowe Price has the discretion to purchase some securities that do not meet its normal investment criteria described above, when it believes there is an opportunity for substantial appreciation (such as, for example, T. Rowe Price believes a security could increase in value as a result of a change in management, an extraordinary corporate event, a new product introduction or innovation, or a favorable competitive development).

The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Principal Risks

Equity Securities Risk Although stocks may have the potential to outperform other asset classes over the long term, their prices tend to fluctuate more dramatically over the shorter term. These movements may result from factors affecting individual companies, or from broader influences like changes in interest rates, market conditions, or investor confidence, or announcements of economic, political, or financial information.

Foreign Investment Risk; Emerging Markets Risk; Currency Risk Investments in securities of foreign issuers, securities of companies with significant

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foreign exposure, and foreign currencies can involve additional risks relating to market, industry, political, regulatory, public health, and other conditions. Political, social, diplomatic, and economic developments, U.S. and foreign government action, or threat thereof, such as the imposition of currency or capital blockages, controls, or tariffs, economic and trade sanctions or embargoes, security trading suspensions, entering or exiting trade or other intergovernmental agreements, or the expropriation or nationalization of assets in a particular country, can cause dramatic declines in certain or all securities with exposure to that country and other countries. Sanctions, or the threat of sanctions, may cause volatility in regional and global markets and may negatively impact the performance of various sectors and industries, as well as companies in other countries, which could have a negative effect on the performance of the Fund. In the event of nationalization, expropriation, confiscation, or other government action, intervention, or restriction, the Fund could lose its entire investment in a particular foreign issuer or country. There may be quotas or other limits on the ability of the Fund (or clients of the Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries. Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. Emerging markets securities are subject to greater risks than securities issued in developed foreign markets, including less liquidity, less stringent investor protection and disclosure standards, less reliable

settlement practices, greater price volatility, higher relative rates of inflation, greater political, economic, and social instability, greater custody and operational risks, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater volatility in currency exchange rates, and are more susceptible to environmental problems. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and settlement practices, and lower trading volumes that could lead to greater price volatility and illiquidity. Non-U.S. transaction costs, such as brokerage commissions and custody costs, may be higher than in the United States. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

Small and Mid-Cap Company Risk Market risk and liquidity risk are particularly pronounced for securities of small and medium-sized companies, which may trade less frequently and in smaller volumes than more widely-held securities, and may fluctuate in price more than other securities. Their shares can be less liquid than those of larger

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companies, especially during market declines. Small and medium-sized companies may have limited product lines, markets, or financial resources and may be dependent on a limited management group; they may have been recently organized and have little or no track record of success.

Convertible Securities Risk Convertible securities are subject to the risks of both debt instruments and equity securities. The price of a convertible security may change in response to changes in price of the underlying equity security, the credit quality of the issuer, and interest rates. In general, the values of convertible securities tend to decline as interest rates rise and to rise when interest rates fall. A convertible security generally has less potential for gain or loss than the underlying equity security.

to meet redemptions or other cash needs. Some securities may be subject to restrictions on resale. There can be no assurance that there will be a liquid market for instruments held by the Fund at any time. The Fund may not receive the proceeds from the sale of certain investments for an extended period.

Preferred Stock Risk Like other equity securities, preferred stock is subject to the risk that its value may decrease based on actual or perceived changes in the business or financial condition of the issuer. In addition, changes in interest rates may adversely affect the value of a preferred stock that pays a fixed dividend. Preferred stocks are also subject to additional risks, such as potentially greater volatility and risks related to deferral, non-cumulative dividends, subordination, liquidity, limited voting rights, and special redemption rights.

REIT Risk Investments in REITs may be subject to risks similar to those associated with direct investment in real estate, as well as additional risks associated with equity investments. As a shareholder in a REIT, the Fund, and indirectly the Fund’s shareholders, would bear its ratable share of the REIT’s expenses and would at the same time continue to pay its own fees and expenses.

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Restricted Securities Risk The Fund may hold securities that are restricted as to resale under the U.S. federal securities laws, such as securities in certain privately held companies. Such securities may be highly illiquid and their values may experience significant volatility. Restricted securities may be difficult to value.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

Annual Performance

Class I Shares

[MISSING IMAGE: c9ufj563igvrspiprgu1eib7f04u.jpg]

Highest
Quarter:

2Q ’20,

22.13%

Lowest
Quarter:

1Q ’20,

–19.88%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		28.22	%		14.39	%		11.17	%
	Return After Taxes on Distributions		27.32	%		12.47	%		9.55	%
	Return After Taxes on Distributions and Sales of Fund Shares		17.14	%		11.25	%		8.69	%
Russell 1000 Index (reflects no deduction for fees, expenses, or taxes)			26.53	%		15.52	%		12.76	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

Portfolio Manager(s):

Shawn T. Driscoll is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since April 2022.

Joe Fath, CPA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since its inception (February 2018).

Ryan S. Hedrick is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since January 2023.

Ann M. Holcomb, CFA is a Vice President and Portfolio Manager at T. Rowe Price. She has managed the Fund since October 2021.

Jason Nogueira, CFA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since October 2021.

Jason Benjamin Polun, CFA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since October 2021.

PURCHASE AND SALE OF FUND SHARES

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TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund

INVESTMENT OBJECTIVE

The Fund seeks a level of income that is consistent with the current rate of inflation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.10%
Total Annual Fund Operating Expenses			0.10%
Expense Reimbursement			(0.10)%
Total Annual Fund Operating Expenses after Expense Reimbursement(1)			0.00%

(1)

Example

preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$0			$22			$46			$118

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in bonds. The Fund invests in a diversified portfolio of short- and intermediate-term investment-grade bonds. The Fund’s investments may include inflation-linked securities, including Treasury Inflation Protected Securities, as well as corporate, government, mortgage-backed, and asset-backed securities. The Fund may also invest in money market securities, bank obligations, collateralized mortgage obligations, and foreign securities. The Fund will invest at least 20% of its net assets in inflation-linked securities, although normally the Fund expects to invest 50% or more of its net assets in inflation-linked securities. Although the Fund may invest in debt securities of any maturity or duration, the Fund will normally maintain a weighted average duration within plus (+) or minus (-) two years of the duration of the Bloomberg U.S. 1-5 Year Treasury TIPS Index. As of December 31, 2023, the duration of the Bloomberg U.S. 1-5 Year Treasury TIPS Index was approximately 2.64 years and its duration ranged from 0.09 years to 5.24 years over the past three years. Duration, which is expressed in years, is a calculation that attempts to measure the price sensitivity of a bond or bond fund to changes in interest rates. The longer a bond fund’s duration, the more sensitive that fund should be to changes

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in interest rates. For example, if interest rates rise by 1% and a fixed-rate bond has a duration of 5 years, it is estimated that the principal value of the bond will decrease by approximately 5%.

The Fund will only purchase securities that are rated within the four highest credit rating categories (AAA, AA, A, BBB, or equivalent) at the time of purchase by at least one major credit rating agency or, if unrated, determined to be of comparable quality by the Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”). In the event that a security is downgraded after its purchase by the Fund, the Fund may continue to hold the security if T. Rowe Price considers that doing so would be consistent with the Fund’s investment objective. The Fund may invest up to 20% of its total assets in non-U.S. dollar-denominated securities and may invest without limitation in U.S. dollar-denominated securities of foreign issuers; any such securities may include investments in emerging markets. The Fund may hold a portion of its assets in cash or cash equivalents.

The Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, for hedging purposes, to manage inflation risk, to adjust various portfolio characteristics, including the duration (interest rate volatility) of the Fund’s portfolio, or as a substitute for direct investments in securities. Such derivatives may include futures contracts, interest rate swaps, including inflation swaps, total return swaps, credit default swaps, and options. The Fund may also, but will not necessarily, engage in foreign currency transactions, including forward contracts, options on currencies, futures contracts, and swap contracts, to seek to hedge or to attempt to protect against adverse changes in currency exchange rates or otherwise to adjust the currency exposures within the Fund’s portfolio. Use of derivatives by the Fund may create investment leverage.

In making investment decisions for the Fund, T. Rowe Price considers that investments in inflation-linked securities should provide some protection against the impact of inflation. T. Rowe Price bases its investment decisions on the outlooks for inflation, interest rates, and the overall economy, as well as the prices and yields of the various securities in which the Fund may invest. For example, if T. Rowe Price’s outlook is one of high or rising inflation, the Fund may hold more than 50% of its assets in inflation-linked securities and, if T. Rowe Price believes inflation will be low or

falling, the Fund may focus more on securities that are not indexed to inflation (within the Fund’s investment program). If interest rates are expected to fall, T. Rowe Price may purchase securities with longer maturities in an attempt to seek higher yields and/or capital appreciation. Conversely, if interest rates are expected to rise, T. Rowe Price may seek securities with shorter maturities.

The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Principal Risks

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securities are subject to interest rate risk (the risk that the value of a fixed income security will fall when interest rates rise), extension risk (the risk that the average life of a security will be extended through a slowing of principal payments), prepayment risk (the risk that a security will be prepaid and the Fund will be required to reinvest at a less favorable rate), duration risk (the risk that longer-term securities may be more sensitive to interest rate changes), inflation risk (the risk that as inflation increases, the present value of the Fund’s fixed income investment typically will decline), and credit risk.

Inflation-Linked Securities Risk Such securities may change in value in response to actual or anticipated changes in inflation rates in a manner unanticipated by the Fund’s portfolio manager or investors generally. Inflation-linked securities are subject to fixed income securities risks. When inflation is low, declining, or negative, the Fund’s performance could lag the performance of more conventional bond funds. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy (or expectations that such policies will change), and the Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors.

Inflation Protection Risk The Fund’s investments may not provide protection against the adverse effects of an increase in inflation over certain periods or at all. In addition, investments in companies that offer protection from accelerating inflation may underperform other investments. Any inflation protection provided by the Fund may not be sufficient to offset any adverse effects of an increase in inflation on the economy or companies generally. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy (or expectations that such policies will change), and the Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors.

repurchase agreements, reverse repurchase agreements, swap transactions, and other derivatives transactions, and to the counterparty’s ability or willingness to perform in accordance with the terms of the transaction. The value of such transactions to the Fund will depend on the willingness and ability of the counterparty to perform its obligations, including among other things the obligation to return collateral or margin to the Fund. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances.

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Sanctions, or the threat of sanctions, may cause volatility in regional and global markets and may negatively impact the performance of various sectors and industries, as well as companies in other countries, which could have a negative effect on the performance of the Fund. In the event of nationalization, expropriation, confiscation, or other government action, intervention, or restriction, the Fund could lose its entire investment in a particular foreign issuer or country. There may be quotas or other limits on the ability of the Fund (or clients of the Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries. Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. Emerging markets securities are subject to greater risks than securities issued in developed foreign markets, including less liquidity, less stringent investor protection and disclosure standards, less reliable settlement practices, greater price volatility, higher relative rates of inflation, greater political, economic, and social instability, greater custody and operational risks, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater volatility in currency exchange rates, and are more susceptible to environmental problems. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and

outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and settlement practices, and lower trading volumes that could lead to greater price volatility and illiquidity. Non-U.S. transaction costs, such as brokerage commissions and custody costs, may be higher than in the United States. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

Mortgage- and Asset-Backed Securities Risk Investments in mortgage- and asset-backed securities subject the Fund to credit risk, interest rate risk, extension risk, and prepayment risk, among other risks. Mortgage-backed and asset-backed securities not issued by a government agency generally involve greater credit risk than securities issued by government agencies. Payment of principal and interest generally depends on the cash flows generated by the underlying assets and the terms of the security. The types of mortgages (for example, residential or commercial mortgages) underlying securities held by the Fund may differ and be affected differently by market factors. The Fund’s investments in mortgage-backed securities may make the Fund’s net asset value more susceptible to economic, market, political, and other developments affecting the residential and commercial real estate markets and the servicing of mortgage loans secured by real estate properties. During periods of difficult economic conditions, delinquencies and losses on commercial mortgage-backed investments in particular generally increase, including as a result of the effects of those conditions on commercial real estate markets, the ability of commercial tenants to make loan payments, and the ability of a property to attract and retain commercial tenants. Investments that receive only the interest portion or the principal portion of payments on the underlying assets may be highly volatile. Litigation with respect to the representations and warranties given in connection with the issuance of mortgage-backed securities can be an important consideration in investing in such securities, and the outcome of any such litigation could

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significantly impact the value of the Fund’s mortgage-backed investments.

incur significant losses. The Fund also runs the risk that deficiencies in the investment adviser’s, subadviser’s, or another service provider’s internal systems or controls will cause losses for the Fund or impair Fund operations.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

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Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Annual Performance

Class I Shares

[MISSING IMAGE: okchnd0pa03pcdl86tagj5tv81ed.jpg]

Highest
Quarter:

2Q ’20,

4.21%

Lowest
Quarter:

3Q ’22,

–3.90%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		3.39	%		3.19	%		2.84	%
	Return After Taxes on Distributions		1.73	%		1.18	%		0.99	%
	Return After Taxes on Distributions and Sales of Fund Shares		2.00	%		1.64	%		1.43	%
Bloomberg U.S. 1-5 Year Treasury TIPS Index (reflects no deduction for fees, expenses, or taxes)			4.45	%		3.29	%		2.96	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

Sub-subadviser(s): T. Rowe Price International Ltd (“T. Rowe Price International”)

T. Rowe Price Hong Kong Limited (“T. Rowe Price Hong Kong”)

Portfolio Manager(s):

Michael K. Sewell, CFA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since February 2020.

PURCHASE AND SALE OF FUND SHARES

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price Real Assets Fund

INVESTMENT OBJECTIVE

The Fund seeks to provide long-term growth of capital.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.13%
Acquired Fund Fees and Expenses			0.01%
Total Annual Fund Operating Expenses(1)			0.14%
Expense Reimbursement			(0.13%)
Total Annual Fund Operating Expenses after Expense Reimbursement(2)			0.01%

(1)

Because Total Annual Fund Operating Expenses include Acquired Fund Fees and Expenses, they may not correspond to the ratios of expenses to average daily net assets shown in the “Financial Highlights” tables in the Prospectus, which reflect the operating expenses of the Fund and do not include Acquired Fund Fees and Expenses.

(2)

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in each share class of the Fund

for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment earns a 5% return each year and that the Fund’s operating expenses are exactly as described in the preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$1			$32			$66			$166

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in “real assets” and securities of companies that derive at least 50% of their profits or revenues from, or commit at least 50% of assets to, real assets and activities related to real assets. The Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”), currently defines real assets broadly and considers them to include any assets that have physical properties, such as energy and natural resources, real estate, basic materials, equipment, utilities and infrastructure, and commodities. Real assets may produce cash flows and subsequent valuations that increase when the overall price level in the economy is rising. The Fund may also invest in companies whose revenues and earnings are expected to rise if the prices of certain real assets rise during a period of general inflation.

The Fund typically invests most of its assets in common stocks and seeks to hold a portfolio of securities and other investments that, over time, should provide some protection against the impact of inflation.The Fund may use both growth and value approaches in selecting investments, and may

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invest in securities issued by companies of any market capitalization. The Fund is likely to maintain a significant portion of its exposure to the real estate industry through investments in real estate investment trusts (“REITs”), which are pooled investment vehicles that typically invest directly in real estate, in mortgages and loans collateralized by real estate, or in a combination of the two. REITs usually specialize in a particular type of property and may concentrate their investments in particular geographical areas. Investments in REITs may provide the Fund with an efficient means of diversifying among various types of property in different regions. The Fund will normally invest in both U.S. and non-U.S. companies, including companies located in emerging markets, and in securities denominated in both U.S. dollars and foreign currencies. There is no limit on the Fund’s investments in non-U.S. companies. The Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, for hedging purposes, to manage inflation risk, to adjust various portfolio characteristics, or as a substitute for direct investments in securities. Such derivatives may include futures contracts, interest rate swaps, total return swaps, and options. The Fund may also, but will not necessarily, engage in foreign currency transactions, including forward contracts, options on currencies, futures contracts, and swap contracts, to seek to hedge or to attempt to protect against adverse changes in currency exchange rates or otherwise to adjust the currency exposures within the Fund’s portfolio. Use of derivatives by the Fund may create investment leverage. The Fund may hold a portion of its assets in cash or cash equivalents.

In selecting securities, T. Rowe Price seeks sectors in equity markets across the globe that are expected to have a low correlation with the overall global equity market in an effort to outperform the market during periods of high or rising inflation. T. Rowe Price invests with an awareness of the global economic backdrop and inflation, as well as its outlook for certain industry sectors and geographic areas. Security selection is based on fundamental, bottom-up analysis that seeks to identify high-quality companies with good appreciation prospects. T. Rowe Price generally favors companies with characteristics such as an attractive industry position, a compelling business model, strong management, and reasonable stock price valuation.

In pursuing the Fund’s investment objective, T. Rowe Price has the discretion to purchase some securities that do not meet its normal investment criteria described above, when it believes there

is an opportunity for substantial appreciation (such as, for example, T. Rowe Price believes a security could increase in value as a result of a change in management, an extraordinary corporate event, a new product introduction or innovation, or a favorable competitive development).

Principal Risks

Real Asset Industry Risk Because the Fund focuses its investments in certain industries that involve activities related to energy, natural resources, real estate, commodities, infrastructure, and other real assets, the Fund is more susceptible to adverse developments affecting one or more of these industries than a Fund that invests more broadly, and may perform poorly during a downturn affecting issuers generally in those industries.

Real Estate Risk; REIT Risk Real estate-related investments may decline in value as a result of factors affecting the real estate industry, such as the supply of real property in certain markets, changes in zoning laws, environmental regulations and other governmental action, delays in completion of construction, changes in real estate values, changes

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in property taxes, levels of occupancy, losses due to natural disasters, and local and regional market conditions. Investments in REITs may be subject to risks similar to those associated with direct investment in real estate, as well as additional risks associated with equity investments. As a shareholder in a REIT, the Fund, and indirectly the Fund’s shareholders, would bear its ratable share of the REIT’s expenses and would at the same time continue to pay its own fees and expenses.

Commodities-Related Investments Risk Commodity prices (including precious metals) can be extremely volatile and exposure to commodities can cause the net asset value of the Fund’s shares to decline or fluctuate in a rapid and unpredictable manner. The values of physical commodities or commodity-linked derivative instruments may be affected by changes in overall market movements, real or perceived inflationary trends, commodity index volatility, changes in interest rates or currency exchange rates, population growth and changing demographics, international economic, political, and regulatory developments, or factors affecting a particular region, industry, or commodity. A liquid secondary market may not exist for certain commodity investments, which may make it difficult for the Fund to sell them at a desirable price or at the price at which it is carrying them.

political, regulatory, public health, and other conditions. Political, social, diplomatic, and economic developments, U.S. and foreign government action, or threat thereof, such as the imposition of currency or capital blockages, controls, or tariffs, economic and trade sanctions or embargoes, security trading suspensions, entering or exiting trade or other intergovernmental agreements, or the expropriation or nationalization of assets in a particular country, can cause dramatic declines in certain or all securities with exposure to that country and other countries. Sanctions, or the threat of sanctions, may cause volatility in regional and global markets and may negatively impact the performance of various sectors and industries, as well as companies in other countries, which could have a negative effect on the performance of the Fund. In the event of nationalization, expropriation, confiscation, or other government action, intervention, or restriction, the Fund could lose its entire investment in a particular foreign issuer or country. There may be quotas or other limits on the ability of the Fund (or clients of the Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries. Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. Emerging markets securities are subject to greater risks than securities issued in developed foreign markets, including less liquidity, less stringent investor protection and disclosure standards, less reliable settlement practices, greater price volatility, higher relative rates of inflation, greater political,

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economic, and social instability, greater custody and operational risks, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater volatility in currency exchange rates, and are more susceptible to environmental problems. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and settlement practices, and lower trading volumes that could lead to greater price volatility and illiquidity. Non-U.S. transaction costs, such as brokerage commissions and custody costs, may be higher than in the United States. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

product lines, markets, or financial resources and may be dependent on a limited management group; they may have been recently organized and have little or no track record of success.

Liquidity Risk Certain securities may be difficult (or impossible) to sell or certain positions may be

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difficult to close out at a desirable time and price, and the Fund may be required to hold an illiquid investment that is declining in value, or it may be required to sell certain illiquid investments at a price or time that is not advantageous in order to meet redemptions or other cash needs. Some securities may be subject to restrictions on resale. There can be no assurance that there will be a liquid market for instruments held by the Fund at any time. The Fund may not receive the proceeds from the sale of certain investments for an extended period.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

Annual Performance

Class I Shares

[MISSING IMAGE: oejg4cad3lrudvrjfvuc2r2rd8od.jpg]

Highest
Quarter:

2Q ’20,

19.49%

Lowest
Quarter:

1Q ’20,

–27.26%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		7.43	%		9.28	%		6.81	%
	Return After Taxes on Distributions		6.77	%		7.92	%		5.58	%
	Return After Taxes on Distributions and Sales of Fund Shares		4.75	%		7.11	%		5.14	%
MSCI ACWI (reflects no deduction for fees or expenses)			22.20	%		11.72	%		8.47	%

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MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

Sub-subadviser(s): T. Rowe Price Australia Limited (“T. Rowe Price Australia”)

Portfolio Manager(s):

Richard A. Coghlan is a Vice President and Portfolio Manager at T. Rowe Price Australia. He has managed the Fund since August 2018.

Christopher Faulkner-MacDonagh is a Portfolio Manager at T. Rowe Price. He has managed the Fund since August 2018.

PURCHASE AND SALE OF FUND SHARES

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund

INVESTMENT OBJECTIVE

The Fund seeks long-term capital appreciation by investing primarily in common stocks of small and mid cap companies.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.06%
Total Annual Fund Operating Expenses			0.06%
Expense Reimbursement			(0.06%)
Total Annual Fund Operating Expenses after Expense Reimbursement(1)			0.00%

(1)

Example

operating expenses are exactly as described in the preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$0			$13			$28			$71

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in equity securities of small and mid cap companies. The Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”), and sub-subadviser, T. Rowe Price Investment Management, Inc. (“T. Rowe Price Investment Management”), currently consider small and mid cap companies to include companies with market capitalizations at the time of purchase that are within the market capitalization range of companies included in either the Russell 2000® Index or the Russell Midcap® Index (as of December 31, 2023, between $16.95 million and $73.32 billion). Equity securities may include common stocks, preferred stocks, securities convertible into common or preferred stock, rights, and warrants.

The Fund typically invests most of its assets in equity securities of U.S. companies, but may invest up to 25% of its total assets in foreign securities and American Depositary Receipts (“ADRs”), including emerging market securities.

The Fund may invest in real estate investment trusts (“REITs”) and exchange-traded funds. The Fund may, to a limited extent, invest in privately held companies and companies that only recently began to trade publicly. The Fund may at times invest

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a substantial portion of its assets in obligations of issuers in one or more market, economic, or industry sectors such as information technology companies. The Fund may (but is not obligated to) use a wide variety of exchange-traded and over-the-counter derivatives, for hedging purposes, to adjust various portfolio characteristics, or as a substitute for direct investments in securities. Such derivatives may include futures contracts, swaps, and options. The Fund may also, but will not necessarily, engage in foreign currency transactions, including forward contracts, options on currencies, futures contracts, and swap contracts, to seek to hedge or to attempt to protect against adverse changes in currency exchange rates or otherwise to adjust the currency exposures within the Fund’s portfolio. Use of derivatives by the Fund may create investment leverage. The Fund may hold a portion of its assets in cash or cash equivalents.

The Fund’s holdings will be widely diversified by industry and issuer. T. Rowe Price and T. Rowe Price Investment Management may employ a growth or value approach in selecting investments. For example, T. Rowe Price or T. Rowe Price Investment Management may seek to identify companies whose price/earnings ratios are attractive relative to the underlying earnings growth rates (e.g., emerging growth companies) and/or companies that appear to be undervalued by various measures and may be temporarily out of favor but have good prospects for capital appreciation.

T. Rowe Price and T. Rowe Price Investment Management generally look for companies with one or more of the following: capable management or plan to improve the business through restructuring; management/employee stock ownership; proven products or services; demonstrated innovative research, product development, and/or marketing; attractive business niches; pricing flexibility; sound financial and accounting practices; a potential or demonstrated ability to grow revenues, earnings, and cash flow consistently; stock price that appears to undervalue growth prospects; low stock price relative to a company’s underlying asset values; above-average dividend yield relative to a company’s peers or a company’s own historical norm; low price/earnings, price/book value, or price/cash flow ratios relative to the Russell 2500 Index, the company’s peers, or its own historical norm; the potential for a catalyst (such as connection to an industry experiencing increasing demand, increased investor

attention, asset sales, strong business prospects, or a change in management) to cause the stock’s price to rise.

In pursuing the Fund’s investment objective, T. Rowe Price and T. Rowe Price Investment Management have the discretion to purchase some securities that do not meet their normal investment criteria described above, when they believe there is an opportunity for substantial appreciation (such as, for example, T. Rowe Price or T. Rowe Price Investment Management believes a security could increase in value as a result of a change in management, an extraordinary corporate event, a new product introduction or innovation, or a favorable competitive development).

T. Rowe Price or T. Rowe Price Investment Management may sell assets for a variety of reasons, including in response to a change in the original investment considerations or to limit losses, adjust the characteristics of the overall portfolio, or redeploy assets into different opportunities.

Principal Risks

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shares can be less liquid than those of larger companies, especially during market declines. Small and medium-sized companies may have limited product lines, markets, or financial resources and may be dependent on a limited management group; they may have been recently organized and have little or no track record of success.

of the Fund (or clients of the Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries. Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of the Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies. Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the U.S. The securities of some non-U.S. companies, especially those in emerging markets, are less liquid and at times more volatile than securities of comparable U.S. companies. Emerging markets securities are subject to greater risks than securities issued in developed foreign markets, including less liquidity, less stringent investor protection and disclosure standards, less reliable settlement practices, greater price volatility, higher relative rates of inflation, greater political, economic, and social instability, greater custody and operational risks, greater risk of new or inconsistent government treatment of or restrictions on issuers and instruments, and greater volatility in currency exchange rates, and are more susceptible to environmental problems. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and settlement practices, and lower trading volumes

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that could lead to greater price volatility and illiquidity. Non-U.S. transaction costs, such as brokerage commissions and custody costs, may be higher than in the United States. In addition, foreign markets can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

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Risk of Investment in Other Funds or Pools The Fund is indirectly exposed to all of the risks of the underlying funds, including ETFs, in which it invests, including the risk that the underlying funds will not perform as expected. ETFs are subject to additional risks, including secondary market trading risks and the risk that an ETF’s shares may trade above or below net asset value. The Fund indirectly pays a portion of the expenses incurred by the underlying funds.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

Annual Performance

Class I Shares

[MISSING IMAGE: ca2od4f0bnta4fm0o8i2fqq3ap5j.jpg]

Highest
Quarter:

2Q ’20,

26.81%

Lowest
Quarter:

1Q ’20,

–24.29%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		19.07	%		13.16	%		10.43	%
	Return After Taxes on Distributions		17.75	%		11.27	%		8.73	%
	Return After Taxes on Distributions and Sales of Fund Shares		12.02	%		10.29	%		8.07	%
Russell 2500 Index (reflects no deduction for fees, expenses, or taxes)			17.42	%		11.67	%		8.78	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

Sub-subadviser(s): T. Rowe Price Investment Management, Inc. (“T. Rowe Price Investment Management”)

Portfolio Manager(s):

Brian W. H. Berghuis, CFA is a Vice President and Equity Portfolio Manager at T. Rowe Price Investment Management. He has managed the Fund since its inception (February 2018).

Vincent DeAugustino is a Portfolio Manager at T. Rowe Price. He has managed the Fund since June 2022.

Alex Roik, CFA is a Vice President and Associate Portfolio Manager at T. Rowe Price Investment Management. He has managed the Fund since July 2023.

Joshua K. Spencer, CFA is a Vice President, Portfolio Manager, and Research Analyst at T. Rowe Price. He has managed the Fund since March 2019.

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J. David Wagner, CFA is a Vice President and Equity Portfolio Manager at T. Rowe Price Investment Management. He has managed the Fund since its inception (February 2018).

PURCHASE AND SALE OF FUND SHARES

Currently, shares of the Fund are only available to other MassMutual Funds, although, at the discretion of the Trust, shares of the Fund may be offered to a broader range of investors at any

time. Fund shares are redeemable on any business day by written request.

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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MassMutual Select T. Rowe Price U.S. Treasury Long-Term Index Fund

INVESTMENT OBJECTIVE

The Fund seeks a high level of income consistent with capital preservation.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund.

Shareholder Fees (fees paid directly from your investment)

			Class I
Maximum Sales Charge (Load) Imposed on Purchases (as a % of offering price)			None
Maximum Deferred Sales Charge (Load) (as a % of the lower of the original offering price or redemption proceeds)			None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

			Class I
Management Fees			0.00%
Distribution and Service (Rule 12b-1) Fees			None
Other Expenses			0.12%
Total Annual Fund Operating Expenses			0.12%
Expense Reimbursement			(0.12%)
Total Annual Fund Operating Expenses after Expense Reimbursement(1)			0.00%

(1)

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in each share class of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods.The example also assumes that your investment earns a 5% return each year and that the Fund’s operating expenses are exactly as described in the

preceding table. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

			1 Year			3 Years			5 Years			10 Years
Class I			$0			$26			$56			$142

Portfolio Turnover

INVESTMENTS, RISKS, AND PERFORMANCE

Principal Investment Strategies

The Fund seeks to track the investment returns of its benchmark index, the Bloomberg U.S. Long Treasury Bond Index*.

Under normal circumstances, the Fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in securities that are held in its benchmark index and at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in U.S. Treasury securities, which are backed by the full faith and credit of the U.S. Government. The Fund’s subadviser, T. Rowe Price Associates, Inc. (“T. Rowe Price”), invests the remainder of the Fund’s assets in other securities backed by the full faith and credit of the U.S. Government and in shares of a T. Rowe Price internal money fund or short-term bond fund that invests exclusively in securities backed by the full faith and credit of the U.S. Government. Securities backed by the full faith and credit of the U.S. Government include, without limitation, securities issued by Government

“Bloomberg®” and Bloomberg U.S. Long Treasury Bond Index are service marks of Bloomberg Finance L.P. and its affiliates, including Bloomberg Index Services Limited (“BISL”), the administrator of the index (collectively, “Bloomberg”) and have been licensed for use for certain purposes by MassMutual. Bloomberg is not affiliated with MassMutual, and Bloomberg does not approve, endorse, review, or recommend the Fund. Bloomberg does not guarantee the timeliness, accuracy, or completeness of any data or information relating to the Fund.

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National Mortgage Association and other government agencies and certain corporate debt securities guaranteed by U.S. Government agencies.

The dollar-weighted average maturity of the Fund’s portfolio will normally exceed 10 years, and it will vary consistent with the dollar-weighted average maturity of the benchmark index.

The Bloomberg U.S. Long Treasury Bond Index is an index consisting of U.S. dollar-denominated, fixed rate nominal debt issued by the U.S. Treasury with maturities of 10 years or more. The Fund does not attempt to fully replicate the index by holding each of the bonds represented in the index. Instead, the Fund seeks to track the returns of the index and more efficiently replicate the key risk factors of the index (such as maturity, duration, and credit quality) by attempting to capitalize on market inefficiencies through structural portfolio positioning and via small tactical bets on inflation, duration, and yield curve positioning.

U.S. Treasury securities in which the Fund may invest include Treasury bills, notes, and bonds (which includes Treasury STRIPS), as well as Treasury inflation protected securities. The Fund buys and sells U.S. Treasury futures, which are futures contracts on U.S. Treasury bonds or notes, and options on such instruments, to gain efficient exposure to U.S. Treasury security prices, help realign the portfolio with the benchmark index, adjust its sensitivity to interest rate changes, and/or manage cash flows into and out of the Fund. Interest rate futures are also used to manage the Fund’s exposure to interest rate changes or to adjust portfolio duration. Use of derivatives by the Fund may create investment leverage.

The Fund may purchase and sell securities on a when-issued, delayed delivery, to-be-announced, or forward commitment basis.

The Fund may sell securities to better align its portfolio with the characteristics of the Bloomberg U.S. Long Treasury Bond Index and will generally seek to sell securities that have been removed from the index within a reasonable timeframe taking into consideration market conditions.

The Fund expects that it will engage in active and frequent trading and so will typically have a relatively high portfolio turnover rate.

Principal Risks

Fixed Income Securities Risk The values of fixed income securities typically will decline during periods of rising interest rates, and can also decline in response to changes in the financial condition of the issuer, borrower, counterparty, or underlying collateral assets, or changes in market, economic, industry, political, regulatory, public health, and other conditions affecting a particular type of security or issuer or fixed income securities generally. Certain events, such as market or economic developments, regulatory or government actions, natural disasters, pandemics, terrorist attacks, war, and other geopolitical events can have a dramatic adverse effect on the debt market and the overall liquidity of the market for fixed income securities. During those periods, the Fund may experience high levels of shareholder redemptions, and may have to sell securities at times when the Fund would otherwise not do so, and potentially at unfavorable prices. Certain securities may be difficult to value during such periods. Fixed income securities are subject to interest rate risk (the risk that the value of a fixed income security will fall when interest rates rise), extension risk (the risk that the average life of a security will be extended through a slowing of principal payments), prepayment risk (the risk that a security will be prepaid and the Fund will be required to reinvest at a less favorable rate), duration risk (the risk that longer-term securities may be more sensitive to interest rate changes), inflation risk (the risk that as inflation increases, the present value of the Fund’s fixed income investment typically will decline), and credit risk.

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otherwise) as unable or unwilling, to make timely principal and/or interest payments, or to otherwise honor its obligations. The Fund may also be exposed to the credit risk of its counterparty to repurchase agreements, reverse repurchase agreements, swap transactions, and other derivatives transactions, and to the counterparty’s ability or willingness to perform in accordance with the terms of the transaction. The value of such transactions to the Fund will depend on the willingness and ability of the counterparty to perform its obligations, including among other things the obligation to return collateral or margin to the Fund. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances.

Leveraging Risk Instruments and transactions, including derivatives, that create leverage may cause the value of an investment in the Fund to be more volatile, could result in larger losses than if they were not used, and tend to compound the effects of other risks.

Reinvestment Risk Income from the Fund’s portfolio will decline if and when the Fund invests

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the proceeds from matured, traded, or called debt obligations at market interest rates that are below the portfolio’s current earnings rate. A decline in income could affect the Fund’s overall return.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Performance Information

The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund’s performance from year to year for Class I shares. The table shows how the Fund’s average annual returns for 1 and 5 years, and since inception, compare with those of a broad measure of market performance. The Fund’s name and investment strategy changed on October 5, 2020. The performance results shown below would not necessarily have been achieved had the Fund’s current investment strategy been in effect for the entire period for which performance results are presented. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

Annual Performance

Class I Shares

[MISSING IMAGE: e8ne99d5rr2n7d8uerjg1uhb8tfq.jpg]

Highest
Quarter:

1Q ’20,

20.98%

Lowest
Quarter:

1Q ’21,

–13.70%

Average Annual Total Returns

(for the periods ended December 31, 2023)

		One Year			Five Years			Since Inception (02/09/18)
Class I	Return Before Taxes		1.65	%		-1.84	%		-0.84	%
	Return After Taxes on Distributions		0.28	%		-5.07	%		-3.74	%
	Return After Taxes on Distributions and Sales of Fund Shares		0.95	%		-1.58	%		-0.85	%
Bloomberg U.S. Long Treasury Bond Index (reflects no deduction for fees, expenses, or taxes)			3.06	%		-1.24	%		-0.26	%

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): T. Rowe Price Associates, Inc. (“T. Rowe Price”)

Portfolio Manager(s):

Michael K. Sewell, CFA is a Vice President and Portfolio Manager at T. Rowe Price. He has managed the Fund since January 2022.

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PURCHASE AND SALE OF FUND SHARES

TAX INFORMATION

The Fund intends to make distributions that may be taxed as ordinary income, qualified dividend income, or capital gains, unless you are an investor eligible for preferential tax treatment.

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Additional Information Regarding Investment Objectives and Principal Investment Strategies

Changes to Investment Objectives and Strategies.

Each Fund’s investment objective and strategies are non-fundamental and may be changed by the Board of Trustees (the “Trustees”) of the MassMutual Select Funds (the “Trust”) without shareholder approval.

Note Regarding Percentage Limitations.

All percentage limitations on investments in this Prospectus will apply at the time of investment, and will not be considered violated unless an excess or deficiency occurs or exists immediately after and as a result of the investment, except as may be otherwise specified in the Statement of Additional Information (“SAI”). (As a result, the actual investments making up a Fund’s portfolio may not at a particular time comport with any such limitation due to increases or decreases in the values of securities held by the Fund.) However, if, through a change in values, net assets, or other circumstances, a Fund were in a position where more than 15% of its net assets was invested in illiquid securities, the Fund would take appropriate orderly steps, as deemed necessary, to protect liquidity. With respect to a Fund whose name suggests that the Fund focuses its investments in a particular type of investment or investments, or in investments in a particular industry or group of industries, and that has adopted a policy under Rule 35d-1 under the Investment Company Act of 1940, as amended (the “1940 Act”), such Fund’s policy to invest at least 80% of its net assets in certain investments may be changed by the Trustees upon at least 60 days’ prior written notice to shareholders.

Credit Ratings.

Security ratings are determined at the time of investment based on ratings published by nationally recognized statistical rating organizations; if a security is not rated, it will be deemed to have the same rating as a security determined by the investment adviser or subadviser to be of comparable quality. Unless otherwise stated, if a security is rated by more than one nationally recognized statistical rating organization, the highest rating is used. The Fund may retain any security whose rating has been downgraded after purchase.

Duration.

Duration is a measure of the expected life of a debt security that is used to determine the sensitivity of the security’s value to changes in interest rates. The longer a security’s duration, the more sensitive it will be to changes in interest rates. For example, if interest rates rise by 1%, the value of a debt security with a duration of two years would be expected to decline 2% and the value of a debt security with a duration of four years would be expected to decline 4%. Unlike the maturity of a debt security, which measures only the time until final payment is due, duration takes into account the time until all payments of interest and principal on a security are expected to be made, including how these payments are affected by prepayments and by changes in interest rates. Determining duration may involve estimates of future economic parameters, which may vary from actual future values.

Leverage.

Leverage generally has the effect of increasing the amount of loss or gain a Fund might realize, and may increase volatility in the value of a Fund’s investments. Adverse changes in the value or level of the underlying asset, rate, or index may result in a loss substantially greater than the amount invested in the derivative itself.

Temporary Defensive Positions.

At times, a Fund’s investment adviser or subadviser may determine that market conditions make pursuing a Fund’s basic investment strategy inconsistent with the best interests of its shareholders. At such times, the investment adviser or subadviser may (but will not necessarily), without notice, temporarily use alternative strategies primarily designed to reduce fluctuations in the values of a Fund’s assets. In implementing these defensive strategies, a Fund may hold assets without limit in cash and cash equivalents and in other investments that the investment adviser or subadviser believes to be consistent with the Fund’s best interests. If such a temporary defensive strategy is implemented, a Fund may not achieve its investment objective.

Portfolio Turnover.

Changes are made in a Fund’s portfolio whenever the investment adviser or subadviser believes such changes are desirable. Portfolio turnover rates are generally not a factor in making buy and sell

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decisions. A high portfolio turnover rate will result in higher costs from brokerage commissions, dealer-mark-ups, bid-ask spreads, and other transaction costs and may also result in a higher percentage of short-term capital gains and a lower percentage of long-term capital gains as compared to a fund that trades less frequently (short-term capital gains generally receive less favorable tax treatment in the hands of shareholders than do long-term capital gains). Such costs are not reflected in the Funds’ Total Annual Fund Operating Expenses set forth in the fee tables but do have the effect of reducing a Fund’s investment return.

Non-Principal Investments; Use of Derivatives; Securities Loans; Repurchase Agreements.

A Fund may hold investments that are not included in its principal investment strategies. These non-principal investments are described in the SAI or below under “Additional Information Regarding Principal Risks.” A Fund also may choose not to invest in certain securities described in this Prospectus and in the SAI, even though it has the ability to do so. Certain Funds may engage in transactions involving derivatives as part of their principal investment strategies; the disclosures of the principal investment strategies of those Funds include specific references to those derivatives transactions. Any of the other Funds may engage in derivatives transactions not as part of their principal investment strategies, and Funds that may use certain derivatives as part of their principal investment strategies may use other derivatives (not as part of their principal investment strategies), as well. A Fund may use derivatives for hedging purposes, as a substitute for direct investment, to earn additional income, to adjust portfolio characteristics, including duration (interest rate volatility), to gain exposure to securities or markets in which it might not be able to invest directly, to provide asset/liability management, or to take long or short positions on one or more indexes, securities, or foreign currencies. If a Fund takes a short position with respect to a particular index, security, or currency, it will lose money if the index, security, or currency appreciates in value, or an expected credit or other event that might affect the value of the index, security, or currency fails to occur. Losses could be significant. Derivatives transactions may include, but are not limited to, foreign currency exchange transactions, options, futures contracts, interest rate swaps, interest rate futures contracts, forward contracts, total return swaps, credit default swaps,

and hybrid instruments. A Fund may use derivatives to create investment leverage. See “Additional Information Regarding Principal Risks,” below, and the SAI for more information regarding those transactions.

A Fund may make loans of portfolio securities to broker-dealers and other financial intermediaries of up to 33% of its total assets, and may enter into repurchase agreements. These transactions must be fully collateralized at all times, but involve some risk to a Fund if the other party should default on its obligation and the Fund is delayed or prevented from recovering the collateral, or if the Fund is required to return collateral to a borrower at a time when it may realize a loss on the investment of that collateral. Any losses from the investment of cash collateral received by the Fund will be for the Fund’s account and may exceed any income the Fund receives from its securities lending activities. A repurchase agreement is a transaction in which a Fund purchases a security from a seller, subject to the obligation of the seller to repurchase that security from the Fund at a higher price. A Fund may enter into securities loans and repurchase agreements as a non-principal investment strategy.

Foreign Securities.

The globalization and integration of the world economic system and related financial markets have made it increasingly difficult to define issuers geographically. Accordingly, the Funds intend to construe geographic terms such as “foreign,” “non-U.S.,” “European,” “Latin American,” “Asian,” and “emerging markets” in the manner that affords to the Funds the greatest flexibility in seeking to achieve the investment objective(s) of the relevant Fund. Specifically, unless otherwise stated, in circumstances where the investment objective and/or strategy is to invest (a) exclusively in “foreign securities,” “non-U.S. securities,” “European securities,” “Latin American securities,” “Asian securities,” or “emerging markets” (or similar directions) or (b) at least some percentage of the Fund’s assets in foreign securities, etc., the Fund will take the view that a security meets this description so long as the issuer of a security is tied economically to the particular country or geographic region indicated by words of the relevant investment objective and/or strategy (the “Relevant Language”). For these purposes the issuer of a security is deemed to have that tie if:

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(i) the issuer is organized under the laws of the country or a country within the geographic region suggested by the Relevant Language or maintains its principal place of business in that country or region; or

(ii) the securities are traded principally in the country or region suggested by the Relevant Language; or

(iii) the issuer, during its most recent fiscal year, derived at least 50% of its revenues or profits from goods produced or sold, investments made, or services performed in the country or region

suggested by the Relevant Language or has at least 50% of its assets in that country or region.

In addition, the Funds intend to treat derivative securities (e.g., call options) for this purpose by reference to the underlying security. Conversely, if the investment objective and/or strategy of a Fund limits the percentage of assets that may be invested in “foreign securities,” etc. or prohibits such investments altogether, a Fund intends to categorize securities as “foreign,” etc. only if the security possesses all of the attributes described above in clauses (i), (ii), and (iii).

Disclosure of Portfolio Holdings

A description of the Funds’ policies and procedures with respect to the disclosure of each Fund’s portfolio securities is available in the Funds’ SAI.

Additional Information Regarding Principal Risks

A Fund, by itself, generally is not intended to provide a complete investment program. Investment in the Funds is intended to serve as part of a diversified portfolio of investments. An investment in a Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

The value of your investment in a Fund changes with the values of the investments in the Fund’s portfolio. Many things can affect those values. Factors that may have an important or significant effect on a particular Fund’s portfolio as a whole are called “Principal Risks.” The Principal Risks of each Fund are identified in the foregoing Fund Summaries and are described in this section. Certain Funds may be more susceptible to some risks than others. Although the Funds strive to reach their stated goals, they cannot offer guaranteed results. The value of your investment in a Fund could go down as well as up. You can lose money by investing in the Funds. References in this section to a Fund’s subadviser may include any sub-subadvisers as applicable.

The SAI contains further information about the Funds, their investments and their related risks.

•

Bank Loans Risk

Many of the risks associated with bank loans are similar to the risks of investing in below investment grade debt securities, although

bank loans are typically (though not always) senior and secured, while below investment grade debt securities or investments are often subordinated and unsecured. Senior loans are subject to the risk that a court could subordinate a senior loan, which typically holds the most senior position in the issuer’s capital structure, to presently existing or future indebtedness or take other action detrimental to the holders of senior loans. Changes in the financial condition of the borrower or economic conditions or other circumstances may reduce the capacity of the borrower to make principal and interest payments on such instruments and may lead to defaults. The value of any collateral securing a bank loan may decline after a Fund invests, and there is a risk that the value of the collateral may not be sufficient to cover the amount owed to the Fund. In addition, collateral securing a loan may be found invalid, may be used to pay other outstanding obligations of the borrower under applicable law, or may be difficult to sell. In the event that a borrower defaults, a Fund’s access to the collateral may be limited by bankruptcy and other insolvency laws. There is also the risk that the collateral may be difficult to liquidate, or that a majority of the collateral may be illiquid. In addition, some loans may be unsecured. Unsecured loans generally present a greater risk of loss to the Fund if the issuer defaults. In some cases, the Fund may rely on a third party to administer its interest in a loan, and so is subject to the risk that the third party will be unwilling or unable to perform its obligations. The Fund may invest in a loan by purchasing an indirect interest in the loan held by a third party. In that case, the Fund will be subject to both the

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credit risk of the borrower and of the third party, and the Fund may be unable to realize some or all of the value of its interest in the loan in the event of the insolvency of the third party. The settlement time for certain loans is longer than the settlement time for many other types of investments, and the Fund may not receive the payment for a loan sold by it until well after the sale; that cash would be unavailable for payment of redemption proceeds or for reinvestment. Interests in some bank loans may not be readily marketable and may be subject to restrictions on resale. In some cases, negotiations involved in disposing of indebtedness may require weeks to complete. Consequently, some indebtedness may be difficult or impossible to dispose of readily at what the Fund believes to be a fair price. Some bank loans may be illiquid, and bank loans generally tend to be less liquid than many other debt securities. The lack of a liquid secondary market may make it more difficult for the Fund to assign a value to such instruments for purposes of valuing the Fund’s portfolio and calculating its net asset value (“NAV”). Some loans may not be considered “securities” for certain purposes under the federal securities laws, and purchasers, such as the Fund, therefore may not be entitled to rely on the anti-fraud protections of the federal securities laws.

•

Below Investment Grade Debt Securities Risk

Below investment grade debt securities, which are also known as “junk” or “high yield” bonds, and comparable unrated securities in which a Fund may invest, have speculative characteristics, and changes in economic conditions, the financial condition of the issuer, and/or an unanticipated rise in interest rates or other circumstances are more likely to lead to a weakened capacity to make principal and interest payment than in the case of higher grade securities. Below investment grade debt securities involve greater volatility of price and yield and greater risk of loss of principal and interest than do higher quality securities. In the past, economic downturns or increases in interest rates have, under certain circumstances, resulted in a higher incidence of default by the issuers of these instruments and are likely to do so in the future, especially in the case of highly leveraged issuers. The prices for these instruments may be affected by

legislative and regulatory developments. Some below investment grade debt securities are issued in connection with management buy-outs and other highly leveraged transactions, and may entail substantial risk of delays in payments of principal or interest or of defaults. The inability (or perceived inability) of issuers to make timely payment of interest and principal would likely make the values of securities held by the Fund more volatile and could limit the Fund’s ability to sell its securities at prices approximating the values the Fund has placed on such securities. In the absence of a liquid trading market for securities held by it, a Fund at times may be unable to establish the fair value of such securities. To the extent a Fund invests in securities in the lower rating categories, the achievement of the Fund’s goals is more dependent on the Fund investment adviser’s or subadviser’s investment analysis than would be the case if the Fund were investing in securities in the higher rating categories. Securities that are rated CCC or below by Standard & Poor’s or Caa or below by Moody’s Investors Service, Inc. are generally regarded by the rating agencies as having extremely poor prospects of ever attaining any real investment standing.

•

Cash Position Risk

A Fund may hold a significant portion of its assets in cash or cash equivalents at the sole discretion of the Fund’s investment adviser or subadviser, based on such factors as it may consider appropriate under the circumstances. The portion of a Fund’s assets invested in cash and cash equivalents may at times exceed 25% of the Fund’s net assets. To the extent a Fund holds a significant portion of its assets in cash or cash equivalents, its investments returns may be adversely affected and the Fund may not achieve its investment objective.

•

Commodities-Related Investments Risk

Commodity prices (including precious metals) can be extremely volatile and exposure to commodities can cause the NAV of the Fund’s shares to decline or fluctuate in a rapid and unpredictable manner. The values of physical commodities or commodity-linked derivative investments may be affected by changes in overall market movements, real or perceived inflationary trends, commodity index volatility,

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changes in interest rates or currency exchange rates, population growth and changing demographics, international economic, political and regulatory developments, or factors affecting a particular region, industry, or commodity, such as drought, floods, weather, embargoes, tariffs, and international economic, political, and regulatory developments. The price of a commodity may be affected by demand/supply imbalances in the market for the commodity. Also, a liquid secondary market may not exist for certain commodity investments, which may make it difficult for the Fund to sell them at a desirable price or the price at which it is carrying them. A Fund’s investments in commodities and commodity-related instruments may bear on or be limited by the Fund’s intention or ability to qualify as a “regulated investment company” for U.S. federal income tax purposes. See “Taxation and Distributions” below.

•

Convertible Securities Risk

Convertible securities are bonds, debentures, notes or other debt securities that may be converted at either a stated price or stated rate into shares of common or preferred stock (or cash or other securities of equivalent value), and so are subject to the risks of investments in both debt securities and equity securities. The price of a convertible security may change in response to changes in price of the underlying equity security, the credit quality of the issuer, and interest rates. Due to the conversion feature, convertible debt securities generally yield less than non-convertible securities of similar credit quality and maturity. The values of convertible securities may be interest-rate sensitive and tend to decline as interest rates rise and to rise when interest rates fall. A Fund may invest at times in securities that have a mandatory conversion feature, pursuant to which the securities convert automatically into stock at a specified date and conversion ratio, or that are convertible at the option of the issuer. When conversion is not at the option of the holder, a Fund may be required to convert the security into the underlying stock even at times when the value of the underlying common stock has declined substantially or it would otherwise be disadvantageous to do so.

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Credit Risk

Credit risk is the risk that an issuer, guarantor, or liquidity provider of a fixed income security held by a Fund may be unable or unwilling, or may be perceived (whether by market participants, ratings agencies, pricing services or otherwise) as unable or unwilling, to make timely principal and/or interest payments, or to otherwise honor its obligations. It includes the risk that the security will be downgraded by a credit rating agency; generally, lower credit quality issuers present higher credit risks. An actual or perceived decline in creditworthiness of an issuer of a fixed income security held by the Fund may result in a decrease in the value of the security. It is possible that the ability of an issuer to meet its obligations will decline substantially during the period when the Fund owns securities of the issuer or that the issuer will default on its obligations or that the obligations of the issuer will be limited or restructured. The credit rating assigned to any particular investment does not necessarily reflect the issuer’s current financial condition and does not reflect an assessment of an investment’s volatility or liquidity. Securities rated in the lowest category of investment grade are considered to have speculative characteristics. In addition, below investment grade debt securities (i.e., “junk” or “high yield” bonds) involve greater credit risk, are more volatile, involve greater risk of price declines and may be more susceptible to economic downturn than investment grade securities. If a security held by the Fund loses its rating or its rating is downgraded, the Fund may nonetheless continue to hold the security in the discretion of the investment adviser or subadviser. In the case of asset-backed or mortgage-related securities, changes in the actual or perceived ability of the obligors on the underlying assets or mortgages may affect the values of those securities.

The Fund may also be exposed to the credit risk of its counterparty to repurchase agreements, reverse repurchase agreements, swap transactions, and other derivatives transactions, and to the counterparty’s ability or willingness to perform in accordance with the terms of the transaction. The value of such transactions to the Fund will depend on the willingness and ability of the counterparty to

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perform its obligations, including among other things the obligation to return collateral or margin to the Fund. If a counterparty becomes bankrupt or otherwise fails to perform its obligations under a derivative contract due to financial difficulties, the Fund may experience significant delays in obtaining any recovery under the derivative contract in a bankruptcy or other reorganization proceeding. The Fund may obtain only a limited recovery or may obtain no recovery in such circumstances. In the event of a counterparty’s (or its affiliate’s) insolvency, the possibility exists that a Fund’s ability to exercise remedies, such as the termination of transactions, netting of obligations, and realization on collateral, could be stayed or eliminated under special resolution regimes adopted in the United States, the European Union, the United Kingdom, and various other jurisdictions. Among other things, such regimes provide government authorities with broad authority to intervene when a financial institution is experiencing financial difficulty.

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Currency Risk

Because foreign securities normally are denominated and traded in foreign currencies, the value of a Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, currency exchange control regulations, intervention (or failure to intervene) by the U.S. or foreign governments in currency markets, foreign withholding taxes, and restrictions or prohibitions on the repatriation of foreign currencies. A Fund may, but will not necessarily, engage in foreign currency transactions in order to protect against fluctuations in the values of holdings denominated in or exposed to other currencies, or, for certain Funds, to generate additional returns. Derivatives transactions providing exposure to foreign currencies may create investment leverage. A Fund’s investment in foreign currencies may increase the amount of ordinary income recognized by the Fund.

Officials in foreign countries may from time to time take actions in respect of their currencies which could significantly affect the value of a Fund’s assets denominated in those currencies or the liquidity of such investments. For example, a foreign government may unilaterally devalue its currency against other currencies, which would typically have the

effect of reducing the U.S. dollar value of investments denominated in that currency. A foreign government may also limit the convertibility or repatriation of its currency or assets denominated in its currency, which would adversely affect the U.S. dollar value and liquidity of investments denominated in that currency. In addition, although at times most of a Fund’s income may be received or realized in foreign currencies, the Fund will be required to compute and distribute its income in U.S. dollars. As a result, if the exchange rate for any such currency declines after the Fund’s income has been earned and translated into U.S. dollars but before payment to shareholders, the Fund could be required to sell portfolio investments to make such distributions. Similarly, if a Fund incurs an expense in a foreign currency and the exchange rate changes adversely to the Fund before the expense is paid, the Fund would have to convert a greater amount of U.S. dollars to pay for the expense at that time than it would have had to convert at the time the Fund incurred the expense. Investments in foreign currencies themselves (directly or through derivatives transactions) may be highly volatile and may create investment leverage.

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Cyber Security and Technology Risk

The Funds and their service providers (including the Funds’ investment adviser, subadviser, custodian, and transfer agent) are subject to operational and information security risks, including those resulting from cyber-attacks and other technological issues. Technological issues or failures, or interference or attacks by “hackers” or others, may have the effect of disabling or hindering the Funds’ operations or the operations of a service provider to the Funds. There are inherent limitations in business continuity plans and technology systems designed to prevent cyber-attacks and avoid operational incidents, including the possibility that certain risks have not been identified. The Funds’ investment adviser does not control the cyber security plans and systems put in place by third-party service providers, and such third-party service providers may have limited indemnification obligations to the Funds’ investment adviser or the Funds, each of whom could be negatively impacted as a result. Any problems relating to the performance and effectiveness of

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security procedures used by a Fund or its service providers to protect a Fund’s assets, such as algorithms, codes, passwords, multiple signature systems, encryption, and telephone call-backs, may have an adverse impact on an investment in a Fund. Similar risks also are present for issuers of securities in which the Funds invest, which could result in material adverse consequences for such issuers, and may cause a Fund’s investment in such securities to lose value. Furthermore, geopolitical tensions may have increased the scale and sophistication of deliberate cyber-attacks, particularly those from nation-states or from entities with nation-state backing.

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Defaulted and Distressed Securities Risk

Defaulted securities risk refers to the uncertainty of repayment of defaulted securities and obligations of distressed issuers. Because the issuer of such securities is in default and is likely to be in distressed financial condition, repayment of defaulted securities and obligations of distressed issuers (including insolvent issuers or issuers in payment or covenant default, in workout or restructuring, or in bankruptcy or insolvency proceedings) is subject to significant uncertainties. The market will likely be less liquid for distressed or defaulted securities than for other types of securities. Reduced liquidity can affect the valuations of distressed or defaulted securities, make their valuation and sale more difficult, and result in greater volatility. Insolvency laws and practices in foreign countries are different than those in the U.S. and the effect of these laws and practices cannot be predicted with certainty. Investments in defaulted securities and obligations of distressed issuers are considered speculative. To the extent a Fund is invested in distressed securities, its ability to achieve current income for its shareholders may be diminished.

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Derivatives Risk

Derivatives are financial contracts whose values depend upon, or are derived from, the value of an underlying asset, reference rate, or index. Derivatives may relate to stocks, bonds, interest rates, currencies, credit exposures, currency exchange rates, commodities, related indexes, or other assets. The use of derivative instruments may involve risks different from, or greater than, the risks

associated with investing directly in securities and other more traditional investments. Derivatives can be highly volatile and are subject to a number of potential risks described in this Prospectus, including market risk, credit risk, management risk, liquidity risk, and leveraging risk. Derivative products are highly specialized instruments that may require investment techniques and risk analyses different from those associated with stocks and bonds. The use of a derivative requires an understanding not only of the underlying instrument or index but also of the derivative itself, often without the benefit of observing the performance of the derivative under all possible market conditions. (For example, successful use of a credit default swap may require, among other things, an understanding of both the credit of the company to which it relates and of the way the swap is likely to respond to changes in various market conditions and to factors specifically affecting the company.) The use of derivatives involves the risk that a loss may be sustained as a result of the failure of another party to the contract (typically referred to as a “counterparty”) to make required payments or otherwise to comply with the contract’s terms. Derivative transactions can create investment leverage. Losses from derivatives can be substantially greater than the derivatives’ original cost and can sometimes be unlimited. Since the values of derivatives are calculated and derived from the values of other assets, reference rates, or indexes, there is greater risk that derivatives will be improperly valued. Derivatives also involve the risk that changes in the value of a derivative may not correlate perfectly with changes in the value of its underlying asset, rate, or index, and the risk that a derivative transaction may not have the effect or benefit the Fund’s investment adviser or subadviser anticipated. Also, suitable derivative transactions may not be available in all circumstances, and there can be no assurance that a Fund will engage in these transactions when that would be beneficial. A liquid secondary market may not always exist for a Fund’s derivative positions at any time. If a derivative transaction is particularly large or if the relevant market is illiquid (as is the case with many privately negotiated derivatives), it may not be possible to initiate a transaction

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or liquidate a position at an advantageous price or at all. Although the use of derivatives is intended to enhance a Fund’s performance, it may instead reduce returns and increase volatility.

U.S. and non-U.S. legislative and regulatory reforms, including those related to the Dodd-Frank Wall Street Reform and Consumer Protection Act, have resulted in, and may in the future result in, significant regulation of derivative instruments and the Funds’ use of such instruments. Such regulations can, among other things, restrict a Fund’s ability to engage in derivative transactions (for example, by making certain types of derivative instruments or transactions no longer available to a Fund), establish additional margin requirements and/or increase the costs of derivatives transactions, and a Fund may as a result be unable to execute its investment strategies in a manner its investment adviser or subadviser might otherwise choose. Counterparty risk with respect to derivatives has been and may continue to be affected by rules and regulations concerning the derivatives market. Some derivatives transactions are centrally cleared, and a party to a cleared derivatives transaction is subject to the credit risk of the clearing house and the clearing member through which it holds the position. Credit risk of market participants with respect to derivatives that are centrally cleared is concentrated in a few clearing houses and clearing members, and it is not clear how an insolvency proceeding of a clearing house or clearing member would be conducted, what effect the insolvency proceeding would have on any recovery by a Fund, and what impact an insolvency of a clearing house or clearing member would have on the financial system more generally.

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Futures Contract Risk. A Fund may enter into futures contracts, in which the Fund agrees to buy or sell certain financial instruments or index units or other assets on a specified future date at a specified price or rate. A Fund may also enter into contracts to deliver in the future an amount of one currency in return for an amount of another currency. If a Fund’s investment adviser or subadviser misjudges the direction of interest rates, markets, or foreign exchange rates, a Fund’s overall performance could suffer. The risk of loss could be far

greater than the investment made because a futures contract requires only a small deposit to take a large position. A small change in a futures contract could have a substantial impact on a Fund, favorable or unfavorable. An investor could also suffer losses if it is unable to close out a futures contract because of an illiquid market. Futures are subject to the creditworthiness of the futures commission merchants or brokers and clearing organizations involved in the transactions. In the event of the insolvency of its futures commission merchant or broker, a Fund may be delayed or prevented from recovering some or all of the margin it has deposited with the merchant or broker, or any increase in the value of its futures positions held through that merchant or broker.

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Dollar Roll Transaction Risk

In a dollar roll transaction, a Fund sells mortgage-backed securities for delivery to the buyer in the current month and simultaneously contracts to purchase similar securities on a specified future date from the same party. These types of transactions generally create leverage (see “Leveraging Risk” below). It may be difficult or impossible for a Fund to exercise its rights under a dollar roll transaction in the event of the insolvency or bankruptcy of the counterparty, and the Fund may not be able to purchase the securities or other assets subject to the transaction and may be required to return any collateral it holds.

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Emerging Markets Risk

Investing in emerging market securities poses risks different from, and/or greater than, risks of investing in domestic securities or in the securities of foreign, developed countries. These risks may include, for example, smaller market-capitalizations of securities markets; significant price volatility; illiquidity; limits on foreign investment; and possible limits on repatriation of investment income and capital. Future economic or political events or crises could lead to price controls, forced mergers, expropriation or confiscatory taxation, seizure, nationalization, or the creation of government monopolies. The currencies of emerging market countries may experience significant declines against the U.S. dollar, and devaluation may occur subsequent to investments in those currencies by a Fund.

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Inflation and rapid fluctuations in inflation rates have had, and may continue to have, negative effects on the economies and securities markets of certain emerging market countries. Although many of the emerging market securities in which a Fund may invest are traded on securities exchanges, they may trade in limited volume, and the exchanges may not provide all of the conveniences or protections provided by securities exchanges in more developed markets.

Additional risks of emerging market securities may include greater social, economic, and political uncertainty and instability; more substantial governmental involvement in the economy; less governmental supervision and regulation; greater custody and operational risks; unavailability of currency hedging techniques; less stringent investor protection and disclosure standards; less reliable settlement practices; companies that are newly organized and small; differences in auditing and financial reporting standards, which may result in unavailability or unreliability of material information about issuers or instruments; less developed legal, regulatory, and accounting systems; and greater environmental risk. Many emerging market countries are highly reliant on international trade and exports, including the export of commodities. Their economies may be significantly impacted by fluctuations in commodity prices and the global demand for certain commodities. In addition, pandemics and outbreaks of contagious diseases may exacerbate pre-existing problems in emerging market countries with less established health care systems. In addition, emerging securities markets may have different clearance and settlement procedures, which may be unable to keep pace with the volume of securities transactions or otherwise make it difficult to engage in such transactions. Settlement of securities transactions in emerging markets may be subject to risk of loss and may be delayed more often than transactions settled in the United States, in part because a Fund will need to use brokers and counterparties that are less well capitalized, and custody and registration of assets in some countries may be unreliable compared to more developed countries. Settlement problems may cause a Fund to miss attractive investment opportunities, hold a portion of its assets in

cash pending settlement, or be delayed in disposing of a portfolio security. It may be more difficult to obtain and/or enforce a judgment in a court outside the U.S., and a judgment against a foreign government may be unenforceable.

Frontier markets, a subset of emerging markets, generally have smaller economies and less mature capital markets than emerging markets. As a result, the risks of investing in emerging market countries are magnified in frontier market countries. Frontier markets are more susceptible to having abrupt changes in currency values, less mature markets and settlement practices, and lower trading volumes that could lead to greater price volatility and illiquidity.

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Equity Securities Risk

Although stocks may have the potential to outperform other asset classes over the long term, their prices tend to fluctuate more dramatically over the shorter term. These movements may result from factors affecting individual companies, or from broader influences like changes in interest rates, market conditions, or investor confidence, or announcements of economic, political, or financial information.

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Fixed Income Securities Risk

The values of debt securities change in response to interest rate changes. In general, as interest rates rise, the value of a debt security is likely to fall. This risk is generally greater for obligations with longer maturities or for debt securities that do not pay current interest (such as zero-coupon securities). Debt securities with variable and floating interest rates can be less sensitive to interest rate changes, although, to the extent a Fund’s income is based on short-term interest rates that fluctuate over short periods of time, income received by the Fund may decrease as a result of a decline in interest rates. The value of a debt security also depends on the issuer’s actual or perceived credit quality or ability to pay principal and interest when due. The value of a debt security is likely to fall if an issuer or the guarantor of a security is unable or unwilling (or is perceived to be unable or unwilling) to make timely principal and/or interest payments or otherwise to honor its obligations or if the debt security’s

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rating is downgraded by a credit rating agency. The value of a debt security can also decline in response to changes in market, economic, industry, political, regulatory, public health, and other conditions that affect a particular type of debt security or issuer or debt securities generally. Certain events, such as market or economic developments, regulatory or government actions, natural disasters, pandemics, terrorist attacks, war, and other geopolitical events can have a dramatic adverse effect on the debt market and the overall liquidity of the market for fixed income securities.

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Extension Risk. During periods of rising interest rates, the average life of certain types of securities may be extended because of slower than expected principal payments. This may lock in a below-market interest rate, increase the security’s duration, and reduce the value of the security.

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Prepayment Risk. Prepayment risk is the risk that principal of a debt obligation will be repaid at a faster rate than anticipated. In such a case, a Fund may lose the benefit of a favorable interest rate for the remainder of the term of the security in question, and may only be able to reinvest the amount of the prepayment at a less favorable rate.

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Interest Rate Risk. The values of bonds and other debt instruments usually rise and fall in response to changes in interest rates. The values of debt instruments generally increase in response to declines in interest rates and decrease in response to rises in interest rates. Interest rates can also change in response to the supply and demand for credit, government and/or central bank monetary policy and action, inflation rates, and other factors. Interest rate risk is generally greater for fixed-rate instruments than floating-rate instruments and for investments with longer durations or maturities. Some investments give the issuer the option to call or redeem an investment before its maturity date. If an issuer calls or redeems an investment during a time of declining interest rates, a Fund might have to reinvest the proceeds in an investment offering a lower yield, and therefore might not benefit from any increase in value as a result of declining interest rates. Negative or very low interest rates could magnify the risks associated

with changes in interest rates. In general, changing interest rates, including rates that fall below zero, could have unpredictable effects on markets and may expose fixed income and related markets to heightened levels of interest rate volatility and liquidity risk. The risks associated with rising interest rates may be particularly acute in the current market environment because the U.S. Federal Reserve Board has been raising interest rates and may continue to do so.

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Foreign Investment Risk

Investments in securities of foreign issuers, securities of companies with significant foreign exposure, and foreign currencies can involve additional risks relating to market, industry, political, regulatory, public health, and other conditions. Political, social, diplomatic, and economic developments, U.S. and foreign government action, or threat thereof, such as the imposition of currency or capital blockages, controls, or tariffs, economic and trade sanctions or embargoes, security trading suspensions, entering or exiting trade or other intergovernmental agreements, or the expropriation or nationalization of assets in a particular country, can cause dramatic declines in certain or all securities with exposure to that country and other countries. Sanctions, or the threat of sanctions, may cause volatility in regional and global markets and may negatively impact the performance of various sectors and industries, as well as companies in other countries, which could have a negative effect on the performance of a Fund. Economic or other sanctions imposed on a foreign country or issuer by the U.S., or on the U.S. by a foreign country, could impair a Fund’s ability to buy, sell, hold, receive, deliver, or otherwise transact in certain securities. In the event of nationalization, expropriation, confiscation, or other government action, intervention, or restriction, a Fund could lose its entire investment in a particular foreign issuer or country. Civil unrest, geopolitical tensions, wars, and acts of terrorism are other potential risks that could adversely affect an investment in a foreign security or in foreign markets or issuers generally. There may be quotas or other limits on the ability of a Fund (or clients of a Fund’s investment adviser or subadviser) to invest or maintain investments in securities of issuers in certain countries.

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Enforcing legal rights can be more difficult, costly, and limited in certain foreign countries and with respect to certain types of investments, and can be particularly difficult against foreign governments. Because non-U.S. securities are normally denominated and traded in currencies other than the U.S. dollar, the value of a Fund’s assets may be affected favorably or unfavorably by changes in currency exchange rates, exchange control regulations, and restrictions or prohibitions on the repatriation of non-U.S. currencies.

Income and gains with respect to investments in certain countries may be subject to withholding and other taxes. There may be less information publicly available about a non-U.S. company than about a U.S. company, and many non-U.S. companies are not subject to accounting, auditing, and financial reporting standards, regulatory framework and practices comparable to those in the United States. The securities of some non-U.S. companies are less liquid and at times more volatile than securities of comparable U.S. companies. Non-U.S. transaction costs, such as brokerage commissions and custody costs may be higher than in the United States. In addition, foreign markets can perform differently from U.S. markets and can react differently to market, economic, industry, political, regulatory, geopolitical, public health, and other conditions than the U.S. market.

The willingness and ability of foreign governmental entities to pay principal and interest on government securities depends on various economic factors, including for example the issuer’s balance of payments, overall debt level, and cash-flow considerations related to the availability of tax or other revenues to satisfy the issuer’s obligations. If a foreign governmental entity defaults on its obligations on the securities, a Fund may have limited recourse available to it. The laws of some foreign countries may limit a Fund’s ability to invest in securities of certain issuers located in those countries. Special tax considerations apply to a Fund’s investments in foreign securities. A Fund’s investments in foreign securities or foreign currencies may increase or accelerate the Fund’s recognition of ordinary income and may affect the amount, timing, or character of the Fund’s distributions.

A Fund may invest in foreign securities known as depositary receipts, in the form of American Depositary Receipts (“ADRs”), European Depositary Receipts (“EDRs”), Global Depositary Receipts (“GDRs”), or other similar securities. An ADR is a U.S. dollar-denominated security issued by a U.S. bank or trust company that represents, and may be converted into, a foreign security. An EDR or a GDR is generally similar but is issued by a non-U.S. bank. Depositary receipts are subject to the same risks as direct investment in foreign securities. Depositary receipts may not necessarily be denominated in the same currency as the underlying securities into which they may be converted, and changes in currency exchange rates may affect the value of an ADR investment in ways different from direct investments in foreign securities. Funds may invest in both sponsored and unsponsored depositary receipts. Unsponsored depositary receipts are organized independently and without the cooperation of the issuer of the underlying securities. As a result, available information concerning the issuers may not be as current for unsponsored depositary receipts and the prices of unsponsored depositary receipts may be more volatile than if such instruments were sponsored by the issuer. In addition, the underlying issuers of certain depositary receipts, particularly unsponsored or unregistered depositary receipts, are under no obligation to distribute shareholder communications to the holders of such receipts or to pass through to them any voting rights with respect to the deposited securities. A Fund may therefore receive less timely information or have less control than if it invested directly in the foreign issuer. An investment in an ADR is subject to the credit risk of the issuer of the ADR.

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Frequent Trading/Portfolio Turnover Risk

The length of time a Fund has held a particular security is not generally a consideration in investment decisions. The investment policies of a Fund may lead to frequent changes in the Fund’s investments, particularly in periods of volatile market movements, in order to take advantage of what the Fund’s investment adviser or subadviser believes to be temporary investment opportunities. A change in the securities held by a Fund is known as “portfolio turnover.”

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Portfolio turnover generally involves some expense to a Fund, including brokerage commissions, bid-asked spreads, dealer mark-ups, and other transaction costs on the sale of securities and reinvestments in other securities, and may result in the realization of taxable capital gains (including short-term gains, which are generally treated as ordinary income when distributed to shareholders). The trading costs and tax effects associated with portfolio turnover may adversely affect a Fund’s performance. Consult your tax adviser regarding the effect of a Fund’s portfolio turnover rate on your investments.

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Geographic Focus Risk

When a Fund invests a relatively large percentage of its assets in issuers located in a single country, a small number of countries, or a particular geographic region, the Fund’s performance could be closely tied to the market, currency, economic, political, or regulatory conditions and developments in those countries or that region, and could be more volatile than the performance of more geographically diversified funds.

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Growth Company Risk

Growth company securities tend to be more volatile in terms of price swings and trading volume than many other types of equity securities. Growth companies, especially technology related companies, have seen dramatic rises and falls in stock valuations. Funds that invest in growth companies are subject to the risk that the market may deem these companies’ stock prices over-valued, which could cause steep and/or volatile price swings. Also, since investors buy these stocks because of their expected superior earnings growth, earnings disappointments often result in sharp price declines.

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Hedging Risk

There can be no assurance that a Fund’s hedging transactions will be effective. If a Fund takes a short position in a particular currency, security, or bond market, it will lose money if the currency, security, or bond market appreciates in value, or an expected credit event fails to occur. Any efforts at buying or selling currencies could result in significant losses for the Fund. Further, foreign currency transactions that are intended to hedge the

currency risk associated with investing in foreign securities and minimize the risk of loss that would result from a decline in the value of the hedged currency may also limit any potential gain that might result should the value of such currency increase.

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Indexing Risk

There are several reasons why an index Fund’s performance may not track the performance of the relevant index. For example, the Fund incurs a number of operating expenses not applicable to the index, and incurs costs in buying and selling securities. A Fund may not be fully invested at times, either as a result of cash flows into the Fund or reserves of cash held by the Fund to meet redemptions. The return on the sample of securities purchased by the investment adviser or subadviser, or futures or other derivative positions taken by the investment adviser or subadviser, to replicate the performance of the index may not correlate precisely with the return on the index. Differences between securities held by a Fund and the securities comprising the index may result from legal restrictions, costs, or liquidity constraints, especially during times when a sampling methodology is used.

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Inflation Risk

The value of assets or income from a Fund’s investments will be less in the future as inflation decreases the value of money. As inflation increases, the value of a Fund’s assets can decline as can the value of the Fund’s distributions. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy (or expectations that such policies will change), and a Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors. The market prices of debt securities generally fall as inflation increases because the purchasing power of the future income and repaid principal is expected to be worth less when received by the Fund. Debt securities that pay a fixed rather than variable interest rate are especially vulnerable to inflation risk because variable-rate debt securities may be able to participate, over the long term, in rising interest rates which have historically accompanied long-term inflationary trends.

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Inflation-Linked Securities Risk

Inflation-linked securities are typically fixed income securities whose principal values are periodically adjusted according to a measure of inflation. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy (or expectations that such policies will change), and a Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors. If the index measuring inflation falls, the principal value of an inflation-linked security will be adjusted downward, and consequently the interest payable on the security (calculated with respect to a smaller principal amount) will be reduced. Repayment of the original principal of the security upon maturity (as adjusted for inflation) is guaranteed in the case of U.S. Treasury inflation-linked securities. For securities that do not provide a similar guarantee, the adjusted principal value of the security repaid at maturity may be less than the original principal.

Alternatively, the interest rates payable on certain inflation-linked securities may be adjusted according to a measure of inflation. As a result, the principal values of such securities do not adjust according to the rate of inflation, although the interest payable on such securities may decline during times of falling inflation.

The values of inflation-linked securities are expected to change in response to changes in real interest rates. Real interest rates are tied to the relationship between nominal interest rates and the rate of inflation. If nominal interest rates increase at a faster rate than inflation, real interest rates may rise, leading to a decrease in value of inflation-linked securities. Inflation-linked securities may cause a potential cash flow mismatch to investors, because an increase in the principal amount of an inflation-linked security will be treated as interest income currently subject to tax at ordinary income rates even though investors will not receive repayment of principal until maturity. If a Fund invests in such securities, it will be required to distribute such interest income in order to qualify for treatment as a regulated investment company and eliminate the Fund-level tax, without a corresponding receipt of cash, and therefore may be required

to dispose of portfolio securities at a time when it may not be advantageous to do so in order to make such distributions.

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Inflation Protection Risk

During periods of low inflation, the MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund’s and MassMutual Select T. Rowe Price Real Assets Fund’s attempts to invest in companies that may offer some protection from accelerating inflation could lessen relative returns and cause the Fund to underperform other Funds. Even if the MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund’s and MassMutual Select T. Rowe Price Real Assets Fund’s investments respond well to changes in long-term inflation rates, they may not respond quickly to short-term changes in inflation rates. Further, a period of high inflation may place other strains on the economy that depress the prices of all stocks, even those of companies that typically benefit from high or rising inflation. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy (or expectations that such policies will change), and a Fund’s investments may not keep pace with inflation, which may result in losses to the Fund’s investors.

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Large Company Risk

Large-capitalization stocks as a group could fall out of favor with the market, causing a Fund’s investments in large-capitalization stocks to underperform investments that focus on small- or medium-capitalization stocks. Larger, more established companies may be slow to respond to challenges, including changes to technology or consumer tastes, and may grow more slowly than smaller companies, especially during market cycles corresponding to periods of economic expansion. Market capitalizations of companies change over time.

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Leveraging Risk

The use of leverage has the potential to increase returns to shareholders, but also involves additional risks. A Fund may create leverage by borrowing money (through traditional borrowings or by means of so-called reverse repurchase agreements); certain transactions, including, for example,

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when-issued, delayed-delivery, to-be-announced, and forward commitment purchases, loans of portfolio securities, dollar roll transactions, and the use of some derivatives, can also result in leverage. Leverage will increase the volatility of the Fund’s investment portfolio and could result in larger losses than if it were not used. The use of leverage is considered to be a speculative investment practice and may result in losses to a Fund. Certain derivatives have the potential for unlimited loss, regardless of the size of the initial investment. A Fund will typically pay interest or incur other borrowing costs in connection with leverage transactions.

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LIBOR Transition and Other Reference Benchmarks Risk

The London Interbank Offered Rate (“LIBOR”) was the offered rate for short-term Eurodollar deposits between major international banks. The terms of investments, financings, or other transactions (including certain derivatives transactions) to which the Fund may be a party have historically been tied to LIBOR. In connection with the global transition away from LIBOR led by regulators and market participants, LIBOR was last published on a representative basis at the end of June 2023. Alternative reference rates to LIBOR have been established in most major currencies and the transition to new reference rates continues. Markets in these new rates are developing, but questions around liquidity and how to appropriately mitigate any economic value transfer as a result of the transition remain a concern. The transition away from LIBOR and the use of replacement rates may adversely affect transactions that used LIBOR as a reference rate, financial institutions, funds, and other market participants that engaged in such transactions, and the financial markets generally. The impact of the transition away from LIBOR on the Fund or the financial instruments in which the Fund invests cannot yet be fully determined. In addition, interest rates or other types of rates and indexes which are classed as “benchmarks” have been the subject of ongoing national and international regulatory reform, including under the European Union regulation on indexes used as benchmarks in financial instruments and financial contracts (known as the “Benchmarks Regulation”).

The Benchmarks Regulation has been enacted into United Kingdom law by virtue of the European Union (Withdrawal) Act 2018 (as amended), subject to amendments made by the Benchmarks (Amendment and Transitional Provision) (EU Exit) Regulations 2019 (SI 2019/657) and other statutory instruments. Following the implementation of these reforms, the manner of administration of benchmarks has changed and may further change in the future, with the result that relevant benchmarks may perform differently than in the past, the use of benchmarks that are not compliant with the new standards set by certain supervised entities may be restricted, and certain benchmarks may be eliminated entirely. Additionally, there could be other consequences which cannot be predicted.

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Liquidity Risk

Liquidity risk is the risk that particular investments may be difficult to sell or terminate at approximately the price at which the Fund is carrying the investments. The ability of a Fund to dispose of illiquid positions at advantageous prices may be greatly limited, and a Fund may have to continue to hold such positions during periods when the investment adviser or subadviser otherwise would have sold them. Some securities held by a Fund may be restricted as to resale, may trade in the over-the-counter (“OTC”) market, or may not have an active trading market due to adverse market, economic, industry, political, regulatory, geopolitical, public health, or other conditions, including trading halts, sanctions, or wars. In addition, a Fund, by itself or together with other accounts managed by the investment adviser or subadviser, may hold a position in a security that is large relative to the typical trading volume for that security, which can make it difficult for the Fund to dispose of the position at an advantageous time or price.

Market values for illiquid securities may not be readily available, and there can be no assurance that any fair value assigned to an illiquid security at any time will accurately reflect the price a Fund might receive upon the sale of that security. It is possible that, during periods of extreme market volatility or unusually high and unanticipated levels of redemptions or in the case of a liquidation of

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a Fund, a Fund may be forced to sell large amounts of securities or terminate outstanding transactions at a price or time that is not advantageous in order to meet redemptions or other cash needs or to pay liquidation proceeds. In such a case, the sale proceeds received by a Fund may be substantially less than if the Fund had been able to sell the securities or terminate the transactions in more orderly transactions, and the sale price may be substantially lower than the price previously used by the Fund to value the securities for purposes of determining the Fund’s NAV. To the extent a Fund holds illiquid securities, it may be more likely to pay redemption proceeds in kind.

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Management and Operational Risk

Each Fund is subject to management risk because it relies on the investment adviser’s and/or subadviser’s investment analysis and its selection of investments to achieve its investment objective, and each Fund is subject to the risk that the manager’s assessment of an investment is wrong. A Fund’s investment adviser or subadviser manages the Fund based on its assessment of economic, financial, and market factors and its investment judgment. The investment adviser or subadviser may fail to ascertain properly the appropriate mix of securities for any particular economic cycle. A Fund’s investment adviser or subadviser applies its investment techniques and risk analyses in making investment decisions for the Fund, but there can be no guarantee that they will produce the intended result. Management risk includes the risk that poor security selection will cause a Fund to underperform relative to other funds with similar investment objectives, or that the timing of movements from one type of security to another could have a negative effect on the overall investment performance of the Fund. There can be no assurance that there will be a liquid market for instruments held by the Fund at any time. The Funds are also subject to operational risks resulting from other services provided by the a Fund’s investment adviser, subadviser, and other service providers, including pricing, administrative, accounting, tax, legal, custody, transfer agency, and other operational services. Examples of such operational risks include the possibility of loss caused by inadequate procedures and controls,

human error, and system failures by a service provider. For example, trading delays or errors could prevent a Fund from benefiting from investment gains or avoiding losses. In addition, a service provider may be unable to provide an NAV for a Fund or share class on a timely basis.

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Market Risk

The values of a Fund’s portfolio securities may decline, at times sharply and unpredictably, as a result of unfavorable broad market developments, which may affect securities markets generally or particular industries, sectors, or issuers. The values of a Fund’s investments may decline as a result of a number of such factors, including actual or perceived changes in general economic and market conditions, industry, political, regulatory, geopolitical, public health, and other developments, including the imposition of tariffs or other protectionist actions, changes in interest rates, currency rates, or other rates of exchange, and changes in economic and competitive industry conditions. Likewise, terrorism, war, natural and environmental disasters, and epidemics or pandemics may be highly disruptive to economies and markets. For example, the global pandemic outbreak of the novel coronavirus known as COVID-19 and efforts to contain its spread produced, and may continue to produce, substantial market volatility, severe market dislocations and liquidity constraints in many markets, exchange trading suspensions and closures, higher default rates, and global business disruption, and they may result in future significant adverse effects. Such factors, and the effects of other infectious illness outbreaks, epidemics, or pandemics, may have a significant adverse effect on a Fund’s performance and have the potential to impair the ability of a Fund’s investment adviser, subadviser, or other service providers to serve the Fund and could lead to disruptions that negatively impact the Fund. Different parts of the market and different types of securities can react differently to these conditions. The possibility that security prices in general will decline over short or even extended periods subjects a Fund to unpredictable declines in the value of its shares, as well as potentially extended periods of poor performance. In

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addition, the increasing popularity of passive index-based investing may have the potential to increase security price correlations and volatility. As passive strategies generally buy or sell securities based simply on inclusion and representation in an index, securities’ prices will have an increasing tendency to rise or fall based on whether money is flowing into or out of passive strategies rather than based on an analysis of the prospects and valuation of individual securities. This may result in increased market volatility as more money is invested through passive strategies.

Federal, state, and other governments, their regulatory agencies, or self-regulatory organizations may take actions that affect the regulation of the securities in which a Fund invests or the issuers of such securities in ways that are unforeseeable. The uncertainty surrounding the sovereign debt of a significant number of European Union countries, as well as the status of the Euro, the European Monetary Union, and the European Union itself, has disrupted and may continue to disrupt markets in the U.S. and around the world. The risks associated with investments in Europe may be heightened due to the United Kingdom’s exit from the European Union on January 31, 2020. An agreement between the United Kingdom and the European Union governing their future trade relationship became effective on January 1, 2021. Significant uncertainty remains in the market regarding the ramifications of that development and the arrangements that will apply to the United Kingdom’s relationship with the European Union and other countries following its withdrawal; the range and potential implications of possible political, regulatory, economic, and market outcomes are difficult to predict. There is the potential for decreased trade, capital outflows from the United Kingdom, devaluation of the pound sterling, decreased business and consumer spending and decreased foreign investment in the United Kingdom, and negative effects on the value of a Fund’s investments and/or on a Fund’s ability to enter into certain transactions or value certain investments. If one or more additional countries leave the European Union, or the European Union partially or completely dissolves, the world’s economies and securities markets may be significantly disrupted and

adversely affected. Legislation or regulation also may change the way in which a Fund, the investment adviser, or subadviser is regulated. Such legislation, regulation, or other government action could limit or preclude a Fund’s ability to achieve its investment objective and affect the Fund’s performance.

In addition, military action by Russia in Ukraine could adversely affect global energy and financial markets, and therefore could affect the value of a Fund’s investments, including beyond the Fund’s direct exposure to Russian issuers or nearby geographic regions. The extent and duration of the military action, sanctions, and resulting market disruptions are impossible to predict and could be substantial.

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Mortgage- and Asset-Backed Securities Risk

Investments in mortgage-related and other asset-backed securities are subject to the risk of severe credit downgrades, illiquidity and defaults to a greater extent than many other types of fixed income investments. Mortgage-backed securities, including collateralized mortgage obligations and certain stripped mortgage-backed securities, represent a participation in, or are secured by, mortgage loans. Asset-backed securities are generally structured like mortgage-backed securities, but instead of mortgage loans or interests in mortgage loans, the underlying assets may include such items as motor vehicle installment sale or installment loan contracts, leases of various types of real and personal property, receivables from credit card agreements, and student loan payments. Asset-backed securities also may be backed by pools of corporate or sovereign bonds, loans made to corporations, or a combination of these bonds and loans, commonly referred to as “collateralized debt obligations,” including collateralized bond obligations (“CBOs”) and collateralized loan obligations (“CLOs”). The assets backing collateralized debt obligations may consist in part or entirely of high risk, below investment grade debt obligations (or comparable unrated obligations). In the case of CBOs and certain other collateralized debt obligations, those may include, by way of example, high yield debt, residential privately issued mortgage-related securities, commercial privately issued mortgage-related securities, trust preferred securities, and emerging market debt. In the

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case of CLOs, they may include, among other things, domestic and foreign senior secured loans, senior unsecured loans, and subordinate corporate loans, any or all of which may be rated below investment grade or may be comparable unrated obligations.

Traditional debt investments typically pay a fixed rate of interest until maturity, when the entire principal amount is due. By contrast, payments on mortgage-backed and many asset-backed investments typically include both interest and partial payment of principal. Principal may also be prepaid voluntarily, or as a result of refinancing or foreclosure. The Fund may have to invest the proceeds from prepaid investments in other investments with less attractive terms and yields. As a result, these securities may have less potential for capital appreciation during periods of declining interest rates than other securities of comparable maturities, although they may have a similar risk of decline in market value during periods of rising interest rates. Because the prepayment rate generally declines as interest rates rise, an increase in interest rates will likely increase the duration, and thus the volatility, of mortgage-backed and asset-backed securities. (Duration is a measure of the expected life of a fixed income security that is used to determine the sensitivity of the security’s price to changes in interest rates. Unlike the maturity of a fixed income security, which measures only the time until final payment is due, duration takes into account the time until all payments of interest and principal on a security are expected to be made, including how these payments are affected by prepayments and by changes in interest rates.) Prepayment rates are difficult to predict and the potential impact of prepayments on the value of a mortgage-related or other asset-backed security depends on the terms of the instrument and can result in significant volatility. In addition to interest rate risk (as described under “Interest Rate Risk”), investments in mortgage-backed securities composed of subprime mortgages and investments in CDOs and CLOs backed by pools of high-risk, below investment grade debt securities may be subject to a higher degree of credit risk, valuation risk, and liquidity risk (as described under “Credit Risk,” “Valuation Risk,” and “Liquidity Risk”). During periods of deteriorating

economic conditions, such as recessions or periods of rising unemployment, delinquencies and losses generally increase, sometimes dramatically, with respect to securitizations involving loans, sales contracts, receivables, and other obligations underlying mortgage-related and other asset-backed securities. Litigation with respect to the representations and warranties given in connection with the issuance of mortgage-backed securities can be an important consideration in investing in such securities, and the outcome of any such litigation could significantly impact the value of the Fund’s mortgage-backed investments.

The types of mortgages underlying securities held by the Fund may differ and may be affected differently by market factors. For example, the Fund’s investments in residential mortgage-backed securities will likely be affected significantly by factors affecting residential real estate markets and mortgages generally; similarly, investments in commercial mortgage-backed securities will likely be affected significantly by factors affecting commercial real estate markets and mortgages generally. Furthermore, a Fund’s investments in mortgage-backed securities may make the Fund’s NAV more susceptible to economic, market, political, and other developments affecting the residential and commercial real estate markets and the servicing of mortgage loans secured by real estate properties. During periods of difficult economic conditions, delinquencies and losses on commercial mortgage-backed investments in particular generally increase, including as a result of the effects of those conditions on commercial real estate markets, the ability of commercial tenants to make loan payments, and the ability of a property to attract and retain commercial tenants.

Some mortgage-backed and asset-backed investments receive only the interest portion (“IOs”) or the principal portion (“POs”) of payments on the underlying assets. The yields and values of these investments are extremely sensitive to changes in interest rates and in the rate of principal payments on the underlying assets. IOs tend to decrease in value if interest rates decline and rates of repayment (including prepayment) on the underlying mortgages or assets increase; it is possible that the Fund may lose the entire amount of its

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investment in an IO due to a decrease in interest rates. Conversely, POs tend to decrease in value if interest rates rise and rates of repayment decrease. Moreover, the market for IOs and POs may be volatile and limited, which may make them difficult for the Fund to buy or sell. The values of mortgage-related and other asset-backed securities may be substantially dependent on the servicing of the underlying asset pools, and are therefore subject to risks associated with the negligence or malfeasance by their servicers and to the credit risk of their servicers. In certain situations, the mishandling of related documentation may also affect the rights of securities holders in and to the benefits of the underlying collateral. There may be legal and practical limitations on the enforceability of any security interest granted with respect to underlying assets, or the value of the underlying assets, if any, may be insufficient if the issuer defaults.

The Fund may gain investment exposure to mortgage-backed and asset-backed investments by entering into agreements with financial institutions to buy the investments at a fixed price at a future date. The Fund may or may not take delivery of the investments at the termination date of such an agreement, but will nonetheless be exposed to changes in value of the underlying investments during the term of the agreement. These transactions may create investment leverage.

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Preferred Stock Risk

Like other equity securities, preferred stock is subject to the risk that its value may decrease based on actual or perceived changes in the business or financial condition of the issuer. In addition, if interest rates rise, the dividends on preferred stocks may be less attractive, causing the prices of preferred stocks to decline. Preferred stock may have mandatory sinking fund provisions or call/redemption provisions that can negatively affect its value. In addition, in the event of liquidation of a corporation’s assets, the rights of preferred stock generally are subordinate to the rights associated with a corporation’s debt securities. Preferred stocks are also subject to additional risks, such as potentially greater volatility and risks related to deferral, non-cumulative dividends, subordination, liquidity, limited voting rights, and special redemption rights.

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Real Asset Industry Risk

Because the MassMutual Select T. Rowe Price Real Assets Fund focuses its investments in certain industries that involve activities related to energy, natural resources, real estate, commodities, infrastructure, and other real assets, the Fund is more susceptible to adverse developments affecting one or more of these industries than a Fund that invests more broadly and may perform poorly during a downturn affecting issuers generally in those industries. Companies involved in activities related to real assets can be adversely affected by, among other things, government regulation or deregulation, global political and economic developments, energy and commodity prices, the overall supply and demand for oil and gas, changes in tax zoning laws, environmental issues, and low inflation.

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Real Estate Risk; REIT Risk

Investments in real estate are subject to a number of risks, including losses from casualty, condemnation or natural disasters, and changes in local and general economic conditions, supply and demand, interest rates, zoning laws, environmental regulations and other governmental action, regulatory limitations on rents, property taxes, and operating expenses. The U.S. residential and commercial real estate markets may, in the future, experience and have, in the past, experienced a decline in value, with certain regions experiencing significant losses in property values. Exposure to such real estate may adversely affect Fund performance. An investment in a REIT may be subject to risks similar to those associated with direct ownership of real estate, and may be subject to additional risks, such as poor performance by the manager of the REIT, adverse changes to the tax laws or failure by the REIT to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended (the “Code”), and to the risk of general declines in stock prices. In addition, some REITs have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property. A “mortgage” REIT that invests most or all of its assets in mortgages will be subject to many of the risks described above in respect of mortgage-backed securities. Also, the organizational documents of a REIT may

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contain provisions that make changes in control of the REIT difficult and time-consuming. As a shareholder in a REIT a Fund, and indirectly the Fund’s shareholders, would bear its ratable share of the REIT’s expenses and would at the same time continue to pay its own fees and expenses. Real estate-related investments may entail leverage and may be highly volatile. The securities of small real-estate issuers can be more volatile and less liquid than securities of larger issuers and their issuers can have more limited financial resources.

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Reinvestment Risk

Income from a Fund’s portfolio will decline if and when the Fund invests the proceeds from matured, traded, or called debt obligations at market interest rates that are below the portfolio’s current earnings rate. A decline in income could affect a Fund’s overall return.

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Redemptions by Affiliated Funds

The Funds are an investment option for other MassMutual Funds that are managed as “funds of funds.” As a result, from time to time, a Fund may experience a relatively large redemption and could be required to liquidate assets at inopportune times or at a loss or depressed value, which could cause the value of an investment in the Fund to decline. Similarly, large Fund share purchases may adversely affect a Fund’s performance to the extent that the Fund is delayed in investing new cash and is required to maintain a larger cash position than it ordinarily would, or if the Fund is unable to invest the cash in portfolio securities that it considers as desirable as the Fund’s portfolio securities.

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Restricted Securities Risk

A Fund may hold securities that are restricted as to resale under the U.S. federal securities laws, such as securities in certain privately held companies. There can be no assurance that a trading market will exist at any time for any particular restricted security. Limitations on the resale of these securities may prevent the Fund from disposing of them promptly at reasonable prices or at all. Restricted securities may be highly illiquid. A Fund may have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Restricted securities may be difficult to value because market

quotations may not be readily available, and there may be little publicly available information about the securities or their issuers. The values of restricted securities may be highly volatile.

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Risk of Investment in other Funds or Pools

A Fund may invest in other investment companies or pooled vehicles, including closed-end funds, trusts, and exchange-traded funds (“ETFs”), that are advised by the Fund’s investment adviser or subadviser, as applicable, their affiliates, or by unaffiliated parties, to the extent permitted by applicable law. As a shareholder in an investment company or other pool, the Fund, and indirectly that Fund’s shareholders, bear a ratable share of the investment company’s or pool’s expenses, including, but not limited to, advisory and administrative fees, and the Fund at the same time continues to pay its own fees and expenses. Investment companies or pools in which the Funds may invest may change their investment objectives or policies without the approval of a Fund, in which case a Fund may be forced to withdraw its investment from the investment company or pool at a disadvantageous time. Private investment pools in which the Funds may invest are not registered under the 1940 Act, and so will not offer all of the protections provided by the 1940 Act (including, among other things, independent oversight, protections against certain conflicts of interest, and custodial risks). A Fund is exposed indirectly to all of the risks applicable to any other investment company or pool in which it invests, including that the investment company or pool will not perform as expected. Investments in other investment companies or private pools may be illiquid, may be leveraged, and may be highly volatile.

Investing in other investment companies or private investment vehicles sponsored or managed by the investment adviser or subadviser, as applicable, or affiliates of the investment adviser or subadviser, as applicable, involves potential conflicts of interest. For example, the investment adviser or subadviser, as applicable, or their affiliates may receive fees based on the amount of assets invested in such other investment vehicles, which fees may be higher than the fees the investment adviser or subadviser, as applicable, receives for

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managing the investing Fund. Investment by a Fund in those other vehicles may be beneficial in the management of those other vehicles, by helping to achieve economies of scale or enhancing cash flows. Due to this and other factors, the investment adviser or subadviser, as applicable, will have an incentive to invest a portion of a Fund’s assets in investment vehicles sponsored or managed by the investment adviser or subadviser, as applicable, or their affiliates in lieu of investments by the Fund directly in portfolio securities, and will have an incentive to invest in such investment vehicles over non-affiliated investment companies. The investment adviser or subadviser, as applicable, will have no obligation to select the least expensive or best performing funds available to serve as an underlying investment vehicle. Similarly, the investment adviser or subadviser, as applicable, will have an incentive to delay or decide against the sale of interests held by the Fund in investment vehicles sponsored or managed by the investment adviser or subadviser, as applicable, or their affiliates.

ETFs are subject to many of the same risks applicable to investments in mutual funds generally, including that an ETF will not perform as anticipated, that a Fund will bear its proportionate share of the ETF’s fees and expenses, and that the ETF will lose money. ETFs are also subject to additional risks, including, among others, the risk that the market price of an ETF’s shares may trade above or below its NAV, the risk that an active trading market for an ETF’s shares may not develop or be maintained, the risk that trading of an ETF’s shares may be halted, and the risk that the ETF’s shares may be delisted from the listing exchange. Some ETFs engage in derivatives strategies and use leverage, and as a result their values can be highly volatile. It is possible that an ETF’s performance will diverge from the performance of any index or indexes it seeks to replicate. Because shares of ETFs may be actively traded, their values may be affected in unanticipated ways by the effects of supply and demand in the market for shares of ETFs, activities of short sellers, or unusual speculative activity in their shares. Some ETFs may experience periods of reduced liquidity due to restrictions on trading activity or due to a general lack of investor interest in the asset class represented by the ETF.

Unlike shares of a mutual fund, which can be bought and redeemed from the issuing fund by all shareholders at a price based on NAV, shares of an ETF may be purchased or redeemed directly from the ETF solely by Authorized Participants (“APs”) and only in aggregations of a specified number of shares (“Creation Units”). ETFs may have a limited number of financial institutions that act as APs. To the extent that those APs exit the business, or are unable to or choose not to process creation and/or redemption orders for Creation Units, and no other AP steps forward to create and redeem ETF shares, the ETF’s shares may be more likely to trade at a premium or discount to NAV and possibly face trading halts or delisting.

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Sector Risk

If a Fund allocates a substantial amount of its assets to one or more particular industries or to particular economic, market, or industry sectors, then economic, business, regulatory, or other developments affecting issuers in those industries or sectors may affect the Fund adversely to a greater extent than if the Fund had invested more broadly. Examples might include investments in the technology, health care, or financial sectors or in one or more industries within those sectors. A substantial investment in one or more such industries or sectors has the potential to increase the volatility of a Fund’s portfolio, and may cause the Fund to underperform other mutual funds.

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Short Sales Risk

If a Fund sells a security short, it will make money if the security’s price goes down (in an amount greater than any transaction costs) and will lose money if the security’s price goes up. There is no limit on the amount of money a Fund may lose on a short sale. A Fund may not be able to close out a short sale when it might wish to do so, or may only do so at an unfavorable price. Short sales can involve leverage. When the Fund engages in a short sale, it typically borrows the security sold short. The Fund will ordinarily have to pay a fee or premium to borrow the security and will be obligated to repay to the lender of the security any dividends or interest that accrue on the security during the period of the loan. If the Fund invests the proceeds from short positions

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in other securities the Fund could lose money both on the short positions and on the securities in which it has invested the short proceeds.

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Small and Mid-Cap Company Risk

Small and medium-sized companies may have limited product lines, markets, or financial resources or they may depend on a few key employees. Such companies may have been recently organized and have little or no track record of success. Also, a Fund’s investment adviser or subadviser may not have had an opportunity to evaluate such newer companies’ performance in adverse or fluctuating market conditions. Market risk and liquidity risk are particularly pronounced for stocks of small and medium-sized companies. The securities of small and medium-sized companies may trade less frequently and in smaller volume than more widely held securities. The prices of these securities may fluctuate more sharply than those of other securities, and a Fund may experience some difficulty in establishing or closing out positions in these securities at prevailing market prices. There may be less publicly available information about the issuers of these securities or less market interest in such securities than in the case of larger companies, both of which can cause significant price volatility. Some securities of small and medium-sized issuers may be illiquid or may be restricted as to resale.

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Sovereign Debt Obligations Risk

Investments in debt securities issued by governments or by government agencies and instrumentalities involve the risk that the governmental entities responsible for repayment may be unable or unwilling to pay interest and repay principal when due. A governmental entity’s willingness or ability to pay interest and repay principal in a timely manner may be affected by a variety of factors, including its cash flow, the size of its reserves, its access to foreign exchange, the relative size of its debt service burden to its economy as a whole, and political constraints. A governmental entity may default on its obligations or may require renegotiation or rescheduling of debt payments. Any restructuring of a sovereign debt obligation held by the Fund will likely have a significant adverse effect on the value of the obligation.

In the event of default of sovereign debt, the Fund may be unable to pursue legal action against the sovereign issuer or to realize on collateral securing the debt. The sovereign debt of many non-U.S. governments, including their sub-divisions and instrumentalities, is rated below investment grade (“junk” or “high yield” bonds). Sovereign debt risk may be greater for debt securities issued or guaranteed by emerging and/or frontier market countries. At times, certain emerging and frontier market countries have declared moratoria on the payment of principal and interest on external debt. Certain emerging and frontier market countries have experienced difficulty in servicing their sovereign debt on a timely basis, which has led to defaults and the restructuring of certain indebtedness to the detriment of debtholders.

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U.S. Government Securities Risk

U.S. Government securities include a variety of securities that differ in their interest rates, maturities, and dates of issue. While securities issued or guaranteed by some agencies or instrumentalities of the U.S. Government (such as the Government National Mortgage Association) are supported by the full faith and credit of the United States, securities issued or guaranteed by certain other agencies or instrumentalities of the U.S. Government (such as Federal Home Loan Banks) are supported only by the right of the issuer to borrow from the U.S. Government. Securities issued or guaranteed by certain other agencies and instrumentalities of the U.S. Government (such as Fannie Mae and Freddie Mac) are not supported by the full faith and credit of the U.S. Government and are supported only by the credit of the issuer itself. There is no assurance that the U.S. Government would provide financial support to its agencies and instrumentalities if not required to do so. For securities not backed by the full faith and credit of the United States, a Fund must look principally to the agency or instrumentality issuing or guaranteeing the securities for repayment and may not be able to assert a claim against the United States if the agency or instrumentality does not meet its commitment. Such securities may involve increased risk of loss of principal and interest compared to government debt securities that

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are backed by the full faith and credit of the United States. From time to time, uncertainty regarding the status of negotiations in the U.S. Government to increase the statutory debt ceiling could increase the risk that the U.S. Government may default on payments on certain U.S. Government securities, cause the credit rating of the U.S. Government to be downgraded, increase volatility in the stock and bond markets, result in higher interest rates, reduce prices of U.S. Treasury securities, and/or increase the costs of various kinds of debt. If a U.S. Government-sponsored entity is negatively impacted by legislative or regulatory action (or lack thereof), is unable to meet its obligations, or its creditworthiness declines, the performance of each Fund that holds securities of the entity will be adversely impacted. In addition, certain governmental entities have been subject to regulatory scrutiny regarding their accounting policies and practices and other concerns that may result in legislation, changes in regulatory oversight and/or other consequences that could adversely affect the credit quality, availability, or investment character of securities issued by these entities. Investments in these securities are also subject to, among other things, interest rate risk, prepayment risk, extension risk, and the risk that the value of the securities will fluctuate in response to political, market, or economic developments.

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Valuation Risk

A portion of a Fund’s assets may be valued at fair value pursuant to guidelines that have been approved by the Trustees. A Fund’s assets may be valued using prices provided by a pricing service or, alternatively, a broker-dealer or other market intermediary (sometimes just one broker-dealer or other market intermediary) when other reliable pricing sources may not be available. The Fund, or persons acting on its behalf, may determine a fair value of a security based on such other information as may be available to them. There can be no assurance that any fair valuation of an investment held by a Fund will in fact approximate the price at which the Fund might sell the investment at the time. Technological issues or other service disruption issues involving third-party service providers may

limit the ability of the Fund to value its investment accurately or timely. To the extent a Fund sells a security at a price lower than the price it has been using to value the security, its NAV will be adversely affected. If a Fund has overvalued securities it holds, you may pay too much for the Fund’s shares when you buy into the Fund. If a Fund underestimates the price of its portfolio securities, you may not receive the full market value for your Fund shares when you sell.

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Value Company Risk

A Fund may purchase some equity securities at prices below what the investment adviser or subadviser considers to reflect their actual or potential fundamental values. The Fund bears the risk that the prices of these securities may not increase to reflect what the investment adviser or subadviser believes to be their fundamental value or that the investment adviser or subadviser may have overestimated the securities’ fundamental value or that it may take a substantial period of time to realize that value.

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When-Issued, Delayed Delivery, TBA, and Forward Commitment Transaction Risk

A Fund may purchase securities on a when-issued, delayed delivery, to-be-announced, or forward commitment basis. These transactions involve a commitment by a Fund to purchase securities for a predetermined price or yield, with payments and delivery taking place more than seven days in the future, or after a period longer than the customary settlement period for that type of security. These transactions involve a risk of loss if the value of the securities declines prior to the settlement date. These transactions may create investment leverage. Recently finalized rules of the Financial Industry Regulatory Authority impose mandatory margin requirements for certain types of when-issued, TBA, or forward commitment transactions, with limited exceptions. Such transactions historically have not been required to be collateralized, and mandatory collateralization could increase the cost of such transactions and impose added operational complexity and may increase the credit risk of such transactions to a Fund.

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Management of the Funds

Investment Adviser

MML Investment Advisers, LLC (“MML Advisers”), a Delaware limited liability company, located at 1295 State Street, Springfield, Massachusetts 01111-0001, is the Funds’ investment adviser and is responsible for providing all necessary investment management and administrative services. MML Advisers, formed in 2013, is a wholly-owned subsidiary of Massachusetts Mutual Life Insurance Company (“MassMutual”). Founded in 1851, MassMutual is a mutual life insurance company that provides a broad range of insurance, money management, retirement, and asset accumulation products and services for individuals and businesses. As of September 30, 2023, MML Advisers had assets under management of approximately $42.7 billion.

In 2023, each Fund paid MML Advisers an investment management fee based on a percentage of each Fund’s average daily net assets as follows: 0.18% for the MM Equity Asset Fund; 0.00% for the MassMutual Select T. Rowe Price Bond Asset Fund; 0.00% for the MassMutual Select T. Rowe Price Emerging Markets Bond Fund; 0.00% for the MassMutual Select T. Rowe Price Large Cap Blend Fund; 0.00% for the MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund; 0.00% for the MassMutual Select T. Rowe Price Real Assets Fund; 0.00% for the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund; and 0.00% for the MassMutual Select T. Rowe Price U.S. Treasury Long-Term Index Fund.

A discussion regarding the basis for the Trustees approving any investment advisory contract of the Funds is available in the Funds’ annual report to shareholders dated September 30, 2023.

Subadvisers and Portfolio Managers

MML Advisers contracts with the following subadvisers to help manage the Funds. Subject to the oversight of the Trustees, MML Advisers has the ultimate responsibility to oversee subadvisers and recommend their hiring, termination, and replacement. This responsibility includes, but is not limited to, analysis and review of subadviser performance, as well as assistance in the identification and vetting of new or replacement subadvisers. In addition, MML Advisers maintains responsibility for a number of other important obligations, including, among other things, board reporting, assistance in the annual advisory contract renewal process, and, in general, the performance of all obligations not delegated to a subadviser. MML Advisers also provides advice and recommendations to the Trustees, and performs such review and oversight functions as the Trustees may reasonably request, as to the continuing appropriateness of the investment objective, strategies, and policies of each Fund, valuations of portfolio securities, and other matters relating generally to the investment program of each Fund.

J.P. Morgan Investment Management Inc. (“J.P. Morgan”), located at 383 Madison Avenue, New York, New York 10179, manages the investments of the MM Equity Asset Fund. J.P. Morgan is a wholly-owned subsidiary of JP Morgan Asset Management Holdings Inc., which is a wholly-owned subsidiary of JP Morgan Chase & Co., a bank holding company. As of September 30, 2023, J.P. Morgan and its affiliates had approximately $2.8 trillion in assets under management.

Tim Synder, CFA, CMT

is a portfolio manager of the MM Equity Asset Fund. Mr. Snyder, Executive Director, joined J.P. Morgan in 2003.

Raffaele Zingone, CFA

is a portfolio manager of the MM Equity Asset Fund. Mr. Zingone, Managing Director, joined J.P. Morgan in 1991.

T. Rowe Price Associates, Inc. (“T. Rowe Price”), located at 100 East Pratt Street, Baltimore, Maryland 21202, manages the investments of the MassMutual Select T. Rowe Price Bond Asset Fund, MassMutual Select T. Rowe Price Emerging Markets Bond Fund, MassMutual Select T. Rowe Price Large Cap Blend Fund, MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund, MassMutual Select T. Rowe Price Real Assets Fund, MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund, and MassMutual Select T. Rowe Price U.S. Treasury Long-Term Index Fund. T. Rowe Price, a wholly-owned subsidiary of T. Rowe Price Group, Inc., a publicly-traded financial services holding company, has been managing assets since 1937. In

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addition, each of T. Rowe Price International Ltd (“T. Rowe Price International”) and T. Rowe Price Hong Kong Limited (“T. Rowe Price Hong Kong”) serves as sub-subadviser for the MassMutual Select T. Rowe Price Bond Asset Fund, MassMutual Select T. Rowe Price Emerging Markets Bond Fund, and MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund, T. Rowe Price Australia Limited (“T. Rowe Price Australia”) serves as sub-subadviser for the MassMutual Select T. Rowe Price Real Assets Fund, and T. Rowe Price Investment Management, Inc. (“T. Rowe Price Investment Management”) serves as sub-subadviser for the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund. Each sub-subadviser, subject to the supervision of T. Rowe Price, is authorized to trade securities and make discretionary investment decisions on behalf of a Fund (which includes selecting foreign investments in developed and emerging market countries). T. Rowe Price International is a wholly-owned subsidiary of T. Rowe Price and its address is Warwick Court,
5 Paternoster Square, London, EC4M 7DX, United Kingdom. T. Rowe Price Hong Kong is a wholly-owned subsidiary of T. Rowe Price International and its address is 6/F Chater House, 8 Connaught Road, Central, Hong Kong. T. Rowe Price Australia is a wholly-owned subsidiary of T. Rowe Price International and its address is Level 28, Governor Phillip Tower, 1 Farrer Place, Sydney NSW 2000, Australia. T. Rowe Price Investment Management is a wholly-owned subsidiary of T. Rowe Price and its address is 100 East Pratt Street, Baltimore, Maryland 21202. As of September 30, 2023, T. Rowe Price and its affiliates had approximately $1.35 trillion in assets under management.

T. Rowe Price International and T. Rowe Price Hong Kong were added as sub-subadvisers of the MassMutual Select T. Rowe Price Emerging Markets Bond Fund on July 1, 2023. T. Rowe Price Australia replaced T. Rowe Price Japan, Inc. as a sub-subadviser of the MassMutual Select T. Rowe Price Real Assets Fund on January 1, 2024.

Steve Bartolini, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Bond Asset Fund. Mr. Bartolini is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2010 and his investment experience dates from 2000. During the past five years, Mr. Bartolini has served as a portfolio manager (beginning in June 2016) and, prior to that, as an associate portfolio manager of the U.S. Inflation Protected Bond and U.S. Short-Term Inflation Focused Bond strategies, a member of the fixed income division’s Global Interest Rates and Currencies Strategy Team, and a fixed income trader.

Brian W. H. Berghuis, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund. Mr. Berghuis is a Vice President and Portfolio Manager for T. Rowe Price Investment Management. He joined T. Rowe Price in 1985 and his investment experience dates from 1983. Mr. Berghuis has served as a portfolio manager for T. Rowe Price or T. Rowe Price Investment Management throughout the past five years.

Richard A. Coghlan

is a portfolio manager of the MassMutual Select T. Rowe Price Real Assets Fund. Mr. Coghlan is a Vice President and Portfolio Manager for T. Rowe Price Australia. He joined T. Rowe Price in 2017 and his investment experience dates from 1997. Since joining T. Rowe Price, he has served as a portfolio manager in the Multi-Asset Division of T. Rowe Price. Prior to joining T. Rowe Price, he worked as a fund manager and the head of Multi-Asset Asia for Schroders Investment Management.

Vincent DeAugustino

is a portfolio manager of the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund. Mr. DeAugustino is a Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2015 and his investment experience dates from 2009.

Shawn T. Driscoll

is a portfolio manager of the MassMutual Select T. Rowe Price Large Cap Blend Fund. Mr. Driscoll is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2006 and his investment experience dates from 2003. Mr. Driscoll has served as a portfolio manager for T. Rowe Price throughout the past five years.

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Joe Fath, CPA

is a portfolio manager of the MassMutual Select T. Rowe Price Large Cap Blend Fund. Mr. Fath is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2002 and he has 19 years of investment experience. Prior to serving as a portfolio manager for T. Rowe Price, Mr. Fath served as an equity research analyst and, since 2008, has assisted other T. Rowe Price portfolio managers in managing T. Rowe Price’s U.S. large-cap growth strategies.

Christopher Faulkner-MacDonagh

is a portfolio manager of the MassMutual Select T. Rowe Price Real Assets Fund. Mr. Faulkner-MacDonagh is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2016 and his investment experience dates from 1998. Since joining T. Rowe Price, he has served as a portfolio strategist. Prior to joining T. Rowe Price, he worked as a market strategist at Standard Life Investments and as a senior economist at Ziff Brothers Investments.

Ryan S. Hedrick

is a portfolio manager of the MassMutual Select T. Rowe Price Large Cap Blend Fund. Mr. Hedrick is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2013 and his investment experience dates from 2004. During the past five years, Mr. Hedrick has served as associate portfolio manager of T. Rowe Price’s U.S. Value Equity strategy (beginning in May 2021), and as an associate portfolio manager supporting T. Rowe Price’s U.S. Large-Cap Value strategies (beginning in October 2019).

Ann M. Holcomb, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Large Cap Blend Fund. Ms. Holcomb is a Vice President and Portfolio Manager for T. Rowe Price. She joined T. Rowe Price in 1996 and her investment experience dates from 1995. Ms. Holcomb has served as a portfolio manager for T. Rowe Price throughout the past five years.

Andrew J. Keirle

is a portfolio manager of the MassMutual Select T. Rowe Price Bond Asset Fund. Mr. Keirle is a Vice President and Portfolio Manager for T. Rowe Price International. He joined T. Rowe Price International in 2005 and his investment experience dates from 1996. Mr. Keirle has served as a portfolio manager for T. Rowe Price International throughout the past five years.

Samy Muaddi

is the portfolio manager of the MassMutual Select T. Rowe Price Emerging Markets Bond Fund. Mr. Muaddi is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2006 and his investment experience dates from that time. Mr. Muaddi has served as a portfolio manager for T. Rowe Price throughout the past five years.

Jason Nogueira, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Large Cap Blend Fund. Mr. Nogueira is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2004 and his investment experience dates from 2001. Mr. Nogueira has served as a portfolio manager for T. Rowe Price throughout the past five years.

Ken Orchard, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Bond Asset Fund. Mr. Orchard is a Vice President and Portfolio Manager for T. Rowe Price International. He joined T. Rowe Price International in 2010 and his experience dates from 2004. Since joining T. Rowe Price International, Mr. Orchard has served as a portfolio manager and credit research analyst.

Jason Benjamin Polun, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Large Cap Blend Fund. Mr. Polun is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2003 and his investment experience dates from 1999. Mr. Polun has served as a portfolio manager for T. Rowe Price throughout the past five years.

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Alex Roik, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund. Mr. Roik is a Vice President and Associate Portfolio Manager for T. Rowe Price Investment Management. He joined T. Rowe Price as an associate analyst in 2013 and was promoted to equity analyst in 2016.

Michael K. Sewell, CFA

is the portfolio manager of the MassMutual Select T. Rowe Price Limited Duration Inflation Focused Bond Fund and a portfolio manager of the MassMutual Select T. Rowe Price U.S. Treasury Long-Term Index Fund. Mr. Sewell is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2004 and his investment experience dates from 2006. During the past five years, Mr. Sewell has served as a fixed income trader, a portfolio manager (beginning in February 2020), and an associate portfolio manager (beginning in March 2018) of the U.S. Inflation Protected Bond, U.S. Short-Term Inflation Focused Bond, U.S. Treasury Intermediate-Term Bond, and U.S. Treasury Long-Term Bond strategies.

Joshua K. Spencer, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund. Mr. Spencer is a Vice President, Portfolio Manager, and Research Analyst for T. Rowe Price. He joined T. Rowe Price in 2004 and his investment experience dates from 1998. Prior to joining T. Rowe Price, Mr. Spencer was a research analyst and sector fund portfolio manager specializing in the consumer industry at Fidelity Investments. Mr. Spencer has served as a portfolio manager for T. Rowe Price throughout the past five years.

Saurabh Sud, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Bond Asset Fund. Mr. Sud is a Vice President and Portfolio Manager for T. Rowe Price. He joined T. Rowe Price in 2018 and his investment experience dates from 2006.

J. David Wagner, CFA

is a portfolio manager of the MassMutual Select T. Rowe Price Small and Mid Cap Blend Fund. Mr. Wagner is a Vice President and Portfolio Manager for T. Rowe Price Investment Management. He joined T. Rowe Price in 2000 and his investment experience dates from 1999. Mr. Wagner has served as a portfolio manager for T. Rowe Price or T. Rowe Price Investment Management throughout the past five years.

The Funds’ SAI provides additional information about each portfolio manager’s compensation, other accounts managed by the portfolio managers, and each portfolio manager’s ownership of securities in the relevant Fund.

MML Advisers has received exemptive relief from the Securities and Exchange Commission (“SEC”) to permit it to change subadvisers or hire new subadvisers for a number of the series of the Trust from time to time without obtaining shareholder approval. (In the absence of that exemptive relief, shareholder approval might otherwise be required.) Several other mutual fund companies have received similar relief. MML Advisers believes having this authority is important, because it allows MML Advisers to remove and replace a subadviser in a quick, efficient, and cost-effective fashion when, for example, the subadviser’s performance is inadequate or the subadviser no longer is able to meet a Trust series’ investment objective and strategies. Pursuant to the exemptive relief, MML Advisers will provide to a Fund’s shareholders, within 90 days of the hiring of a new subadviser, an information statement describing the new subadviser. MML Advisers will not rely on this authority for any Fund unless the Fund’s shareholders have approved this arrangement. As of the date of this Prospectus, this exemptive relief is available to each Fund.

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About the Class of Shares – I Shares

Each Fund offers Class I shares. Currently, shares are offered only to certain other MassMutual Funds.

However, at its discretion, the Trust may make shares of the Funds available to other investors at any time.

Buying, Redeeming, and Exchanging Shares

The Funds sell their shares at a price equal to their NAV (see “Determining Net Asset Value” below). Your purchase order will be priced at the next NAV calculated after your order is received in good order by the transfer agent. The Funds will suspend selling their shares during any period when the determination of NAV is suspended. The Funds can reject any purchase order and can suspend purchases if they believe it is in their best interest.

The Funds redeem their shares at their next NAV computed after your redemption request is received by the transfer agent. You will usually receive payment for your shares within seven days after your redemption request is received in good order. Under unusual circumstances, the Funds can also suspend or postpone payment, when permitted by applicable law and regulations. The Funds' transfer agent may temporarily delay for more than seven days the disbursement of redemption proceeds from the Fund account of a "Specified Adult" (as defined in Financial Industry Regulatory Authority Rule 2165) based on a reasonable belief that financial exploitation of the Specified Adult has occurred, is occuring, has been attempted, or will be attempted, subject to certain conditions. Under normal circumstances, each Fund expects to meet redemption requests by using cash or cash equivalents in its portfolio and/or selling portfolio assets to generate cash. Under stressed market conditions, a Fund may pay redemption proceeds using cash obtained through borrowing arrangements that may be available from time to time. To the extent consistent with applicable laws and regulations, the Funds reserve the right to satisfy all or a portion of a redemption request by distributing securities or other property in lieu of cash (“in-kind” redemptions), under both normal and stressed market conditions. Some Funds may be limited in their ability to use assets other than cash to meet redemption requests due to restrictions on ownership of their portfolio assets. The securities distributed in an in-kind redemption will be valued in the same manner as they are valued for purposes of computing the Fund’s NAV. These securities are subject to market

risk until they are sold and may increase or decrease in value prior to converting them into cash. You may incur brokerage and other transaction costs, and could incur a taxable gain or loss for income tax purposes when converting the securities to cash.

Risk of Substantial Redemptions.

If substantial numbers of shares in a Fund were to be redeemed at the same time or at approximately the same time, the Fund might be required to liquidate a significant portion of its investment portfolio quickly to meet the redemptions. A Fund might be forced to sell portfolio securities at prices or at times when it would otherwise not have sold them, resulting in a reduction in the Fund’s NAV; in addition, a substantial reduction in the size of a Fund may make it difficult for the investment adviser or subadviser to execute its investment program successfully for the Fund for a period following the redemptions. Similarly, the prices of the portfolio securities of a Fund might be adversely affected if one or more other investment accounts managed by the investment adviser or subadviser in an investment style similar to that of the Fund were to experience substantial redemptions and those accounts were required to sell portfolio securities quickly or at an inopportune time.

Exchanges

Generally, you can exchange shares of one Fund for the same class of shares of another MassMutual Fund, except as noted below and, with respect to certain series of the MassMutual Premier Funds, in those cases when exchanges are not permitted, as described in the applicable Prospectus under “Placing Transaction Orders—For Shareholders holding shares of theTrust prior to November 1, 2004.” Any share class of another MassMutual Fund may be exchanged for Class R5 shares of the MassMutual U.S. Government Money Market Fund. If Class R5 shares of the MassMutual U.S. Government Money Market Fund are exchanged for Class A shares of another

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MassMutual Fund or Class L shares of the MassMutual Short-Duration Bond Fund, any sales charge applicable to those Class A or Class L shares, as applicable, will typically apply. For individual retirement accounts described in Code Section 408, Class R5 shares of the MassMutual U.S. Government Money Market Fund may only be exchanged for Class A shares of another MassMutual Fund (in which case any sales charge applicable to those Class A shares will typically apply), Class R4 shares of the MassMutual Total Return Bond Fund and MM S&P 500® Index Fund may only be exchanged for Class A shares of another MassMutual Fund (in which case any sales charge applicable to those Class A shares will typically apply), and Class A shares of any other MassMutual Fund may, with respect to the MassMutual Total Return Bond Fund and MM S&P 500 Index Fund, only be exchanged for Class R4 shares. Class L shares of the MassMutual Short-Duration Bond Fund may be exchanged for Class A shares of any other MassMutual Fund. Class A shares of the MassMutual Global Floating Rate Fund, MassMutual Global Credit Income Opportunities Fund, MassMutual Emerging Markets Debt Blended Total Return Fund, and MassMutual Global Emerging Markets Equity Fund may, with respect to the MassMutual Short-Duration Bond Fund, only be exchanged for Class L shares. An exchange is treated as a sale of shares in one MassMutual Fund and a purchase of shares in another MassMutual Fund at the NAV next determined after the exchange request is received and accepted by the transfer agent, MML Advisers, a broker-dealer, or another intermediary authorized for this purpose. You can only exchange into shares of another MassMutual Fund if you meet any qualification requirements of the MassMutual Fund into which you seek to exchange (for example, shares of some MassMutual Funds are not available to purchasers through certain investment channels, and some may be available only to certain types of shareholders). In addition, in limited circumstances, such as those described above, for certain MassMutual Funds the share class available for exchange may not be the same share class as the MassMutual Fund from which you are exchanging. Exchange requests involving a purchase into any MassMutual Fund (except the MassMutual Total Return Bond Fund,

MassMutual Strategic Bond Fund, MassMutual U.S. Government Money Market Fund, MassMutual Inflation-Protected and Income Fund, MassMutual Core Bond Fund, MassMutual Diversified Bond Fund, MassMutual Short-Duration Bond Fund, MassMutual High Yield Fund, MassMutual Clinton Limited Term Municipal Fund, MassMutual Clinton Municipal Fund, MassMutual Clinton Municipal Credit Opportunities Fund, MassMutual Global Floating Rate Fund, MassMutual Global Credit Income Opportunities Fund, and MassMutual Emerging Markets Debt Blended Total Return Fund), however, will not be accepted if you have already made a purchase followed by a redemption involving the same MassMutual Fund within the last 60 days. This restriction does not apply to rebalancing trades executed by any of the MassMutual RetireSMARTSM by JPMorgan Funds, MassMutual Select T. Rowe Price Retirement Funds, and MassMutual Target Allocation Funds. This restriction also does not apply to exchanges made pursuant to certain asset allocation programs, systematic exchange programs, and dividend exchange programs. If you place an order to exchange shares of one MassMutual Fund for another through a broker-dealer or other intermediary then, in order for your exchange to be effected based on the MassMutual Fund’s next determined NAVs, the broker-dealer or other intermediary must receive your request before the close of regular trading on the NYSE, and the broker- dealer or other intermediary must subsequently communicate the request properly to the MassMutual Funds.

Your right to exchange shares is subject to applicable regulatory requirements or contractual obligations. The Funds may limit, restrict, or refuse exchange purchases, if, in the opinion of MML Advisers:

•

you have engaged in excessive trading;

•

a Fund receives or expects simultaneous orders affecting significant portions of the Fund’s assets;

•

a pattern of exchanges occurs which coincides with a market timing strategy; or

•

the Fund would be unable to invest the funds effectively based on its investment objectives

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and policies or if the Fund would be adversely affected.

The Funds reserve the right to modify or terminate the exchange privilege as described above on 60 days written notice.

The Funds do not accept purchase, redemption, or exchange orders or compute their NAVs on days when the New York Stock Exchange (“NYSE”) is closed. This includes: weekends, Good Friday, and all federal holidays other than Columbus Day

and Veterans Day. Certain foreign markets may be open on days when the Funds do not accept orders or price their shares. As a result, the NAV of a Fund’s shares may change on days when you will not be able to buy or sell shares.

How to Invest

To be considered in “good order” purchase orders must be accompanied by sufficient funds. You can pay by Federal Funds wire transfer.

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Frequent Trading Policies

Purchases and exchanges of shares of the Funds should be made for investment purposes only. The Funds discourage, and do not accommodate, excessive trading and/or market timing activity. Excessive trading and/or market timing activity involving the Funds can disrupt the management of the Funds. These disruptions, in turn, can result in increased expenses and can have an adverse effect on Fund performance.

The Trustees, on behalf of the Funds, have approved the policies and procedures adopted by MML Advisers to help identify those individuals or entities MML Advisers determines may be engaging in excessive trading and/or market timing activities. MML Advisers monitors trading activity to uniformly enforce its procedures. However, those who engage in such activities may employ a variety of techniques to avoid detection. Therefore, despite MML Advisers’ efforts to prevent excessive trading and/or market timing trading activities,

there can be no assurance that MML Advisers will be able to identify all those who trade excessively or employ a market timing strategy and curtail their trading in every instance.

The monitoring process involves scrutinizing transactions in fund shares that exceed certain monetary thresholds or numerical limits within a specified period of time. Trading activity identified by either, or a combination, of these factors, or as a result of any other information actually available at the time, will be evaluated to determine whether such activity might constitute excessive trading and/or market timing activity. When trading activity is determined by a Fund or MML Advisers, in their sole discretion, to be excessive in nature, certain account-related privileges, such as the ability to place purchase, redemption, and exchange orders over the internet, may be suspended for such account.

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Determining Net Asset Value

The NAV of each Fund’s shares is determined once daily as of the close of regular trading on the NYSE, on each Business Day. A “Business Day” is every day the NYSE is open. The NYSE normally closes at 4:00 p.m. Eastern Time, but may close earlier on some days. If the NYSE is scheduled to close early, the Business Day will be considered to end as of the time of the NYSE’s scheduled close. A Fund will not treat an intraday disruption in NYSE trading or other event that causes an unscheduled closing of the NYSE as a close of business of the NYSE for these purposes; instead, MML Advisers will determine the fair value of a Fund’s securities in accordance with MML Advisers’ fair valuation policy and procedures. The NYSE currently is not open for trading on New Year’s Day, Martin Luther King, Jr. Day, President’s Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day. Each Fund calculates the NAV of each of its classes of shares by dividing the total value of the assets attributable to that class, less the liabilities attributable to that class, by the number of shares of that class that are outstanding. On holidays and other days when the NYSE is closed, each Fund’s NAV generally is not calculated and the Funds do not anticipate accepting buy or sell orders. However, the value of each Fund’s assets may still be affected on such days to the extent that a Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities and derivative contracts that are actively traded on a national securities exchange or contract market are valued on the basis of information furnished by a pricing service, which provides the last reported sale price, or, in the case of futures contracts, the settlement price, for securities or derivatives listed on the exchange or contract market or the official closing price on the NASDAQ National Market System (“NASDAQ System”), or in the case of OTC securities for which an official closing price is unavailable or not reported on the NASDAQ System, the last reported bid price. Portfolio securities traded on more than one national securities exchange are valued at the last price at the close of the exchange representing the principal market for such securities. Debt securities are valued on the basis of valuations furnished by a pricing service, which generally determines

valuations taking into account factors such as institutional-size trading in similar securities, yield, quality, coupon rate, maturity, type of issue, trading characteristics, and other market data. Shares of other open-end mutual funds are valued at their closing NAVs as reported on each Business Day.

Investments for which market quotations are readily available are marked to market daily based on those quotations. Market quotations may be provided by third-party vendors or market makers, and may be determined on the basis of a variety of factors, such as broker quotations, financial modeling, and other market data, such as market indexes and yield curves, counterparty information, and foreign exchange rates. U.S. Government and agency securities may be valued on the basis of market quotations or using a model that may incorporate market observable data such as reported sales of similar securities, broker quotes, yields, bids, offers, quoted market prices, and reference data. The fair values of OTC derivative contracts, including forward, swap, and option contracts related to interest rates, foreign currencies, credit standing of reference entities, equity prices, or commodity prices, may be based on market quotations or may be modeled using a series of techniques, including simulation models, depending on the contract and the terms of the transaction. The fair values of asset-backed securities and mortgage-backed securities are estimated based on models that consider the estimated cash flows of each debt tranche of the issuer, established benchmark yield, and estimated tranche-specific spread to the benchmark yield based on the unique attributes of the tranche including, but not limited to, prepayment speed assumptions and attributes of the collateral.

The Trustees have designated MML Advisers as the Funds’ “valuation designee,” responsible for determining the fair value, in good faith, of securities and other instruments held by the Funds for which market quotations are not readily available or for which such market quotations or values are considered by MML Advisers or a subadviser to be unreliable (including, for example, certain foreign securities, thinly-traded securities, certain restricted securities, certain initial public offerings, or securities whose values may have been affected by a significant event). It is possible that a significant amount of a Fund’s assets will be

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subject to fair valuation in accordance with MML Advisers’ fair valuation policy and procedures. The fair value determined for an investment by MML Advisers may differ from recent market prices for the investment and may be significantly different from the value realized upon the sale of such investment.

The Funds may invest in securities that are traded principally in foreign markets and that trade on weekends and other days when the Funds do not price their shares. As a result, the values of the Funds’ portfolio securities may change on days when the prices of the Funds’ shares are not calculated. The prices of the Funds’ shares will reflect any such changes when the prices of the Funds’ shares are next calculated, which is the next Business Day. The Funds may use fair value pricing more frequently for securities primarily traded in foreign markets because, among other things, most

foreign markets close well before the Funds value their securities. The earlier close of these foreign markets gives rise to the possibility that significant events, including broad market moves, may have occurred in the interim. The Funds’ investments may be priced based on fair values provided by a third-party vendor, based on certain factors and methodologies applied by such vendor, in the event that there is movement in the U.S. market, between the close of the foreign market and the time the Funds calculate their NAVs. All assets and liabilities expressed in foreign currencies are converted into U.S. dollars at the mean between the buying and selling rates of such currencies against the U.S. dollar at the end of each Business Day.

The Funds’ valuation methods are also described in the SAI.

Taxation and Distributions

Each Fund has elected to qualify each year for treatment as a regulated investment company under Subchapter M of the Code. As a regulated investment company, a Fund will not be subject to U.S. federal income taxes on its ordinary income and net realized capital gains that are distributed in a timely manner to its shareholders. A Fund’s failure to qualify as a regulated investment company would result in corporate level taxation, and consequently, a reduction in income available for distribution to shareholders. In addition, a Fund that fails to distribute at least 98% of its ordinary income for a calendar year and 98.2% of its capital gain net income recognized during the one-year period ending October 31 plus any retained amount from the prior year generally will be subject to a non-deductible 4% excise tax on the undistributed amount.

Certain investors, including most tax-advantaged plan investors, may be eligible for preferential U.S. federal income tax treatment on distributions received from a Fund and dispositions of Fund shares. This Prospectus does not attempt to describe such preferential tax treatment. Any prospective investor that is a trust or other entity eligible for special tax treatment under the Code that is considering purchasing shares of a Fund, including either directly or in connection with a life insurance company separate investment account, should consult its tax advisers about the U.S. federal, state, local, and foreign tax consequences particular to it, as should persons considering

whether to have amounts held for their benefit by such trusts or other entities in shares of a Fund.

Investors are generally subject to U.S. federal income taxes on distributions received in respect of their shares. Distributions are taxed to investors in the manner described herein whether distributed in cash or additional shares of the Fund. Taxes on distributions of capital gains are determined by how long the Fund owned (or is deemed to have owned) the investments that generated them, rather than by how long the shareholder held the shares. Distributions of a Fund’s ordinary income and short-term capital gains (i.e., gains from capital assets held for one year or less) are taxable to a shareholder as ordinary income. Certain dividends may be eligible for the dividends-received deduction for corporate shareholders to the extent they are reported as such. Dividends properly reported as capital gain dividends (relating to gains from the sale of capital assets held by a Fund for more than one year) are taxable in the hands of an investor as long-term capital gain includible in net capital gain and taxed to individuals at reduced rates. Distributions of investment income reported by a Fund as derived from “qualified dividend income” will be taxed in the hands of individuals at the rates applicable to long-term capital gain, provided that holding period and other requirements are met at both the shareholder and Fund level. Distributions from REITs generally do not qualify as qualified dividend income. Funds investing primarily in fixed income instruments generally do

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not expect a significant portion of their distributions to be derived from qualified dividend income.

The Code generally imposes a 3.8% Medicare contribution tax on the net investment income of certain individuals, trusts, and estates to the extent their income exceeds certain threshold amounts. For this purpose “net investment income” generally includes: (i) dividends paid by a Fund, including any capital gain dividends, and (ii) net capital gains recognized on the sale, redemption, exchange, or other taxable disposition of shares of a Fund. Shareholders are advised to consult their tax advisers regarding the possible implications of this additional tax on their investment in a Fund.

The nature of each Fund’s distributions will be affected by its investment strategies. A Fund whose investment return consists largely of interest, dividends, and capital gains from short-term holdings will distribute largely ordinary income. A Fund whose return comes largely from the sale of long-term holdings will distribute largely capital gain dividends. Distributions are taxable to a shareholder even though they are paid from income or gains earned by a Fund prior to the shareholder’s investment and thus were included in the price paid by the shareholder for his or her shares.

Each Fund intends to pay out as dividends substantially all of its net investment income (which comes from dividends and any interest it receives from its investments). Each Fund also intends to distribute substantially all of its net realized long- and short-term capital gains, if any, after giving effect to any available capital loss carryforwards. For each Fund, distributions, if any, are declared and paid at least annually. Distributions may be taken either in cash or in additional shares of the respective Fund at the Fund’s NAV on the first Business Day after the record date for the distribution, at the option of the shareholder. A shareholder that itself qualifies as a regulated investment company is permitted to report a portion of its distributions as “qualified dividend income,” provided certain requirements are met.

Any gain resulting from an exchange or redemption of an investor’s shares in a Fund will generally be subject to tax as long-term or short-term capital gain. A loss incurred with respect to the disposition

of shares of a Fund held for six months or less will be treated as a long-term capital loss to the extent of long-term capital gains dividends received with respect to such shares.

A Fund’s investments in foreign securities may be subject to foreign withholding or other taxes. In that case, the Fund’s yield on those securities would be decreased. Shareholders of a Fund, other than a Fund that makes the election referred to below, generally will not be entitled to claim a credit or deduction with respect to such foreign taxes. If more than 50% of a Fund’s assets at taxable year end consists of the securities of foreign corporations, the Fund may be able to elect to “pass through” to its shareholders foreign income taxes that it pays directly or, under certain circumstances, indirectly through its investments in ETFs or other investment companies that are regulated investment companies for U.S. federal income tax purposes. If any Fund makes this election, a shareholder of the Fund must include its share of those taxes in gross income as a distribution from the Fund and the shareholder will be allowed to claim a credit (or a deduction, if the shareholder itemizes deductions) for such amounts on its U.S. federal tax return subject to certain limitations. Shareholders that are not subject to U.S. federal income tax, and those who invest in a Fund through tax-advantaged accounts (including those who invest through individual retirement accounts or other tax-advantaged retirement plans), generally will receive no benefit from any tax credit or deduction passed through by a Fund. A shareholder that itself qualifies for treatment as a regulated investment company and that qualifies as a “qualified fund of funds” may elect to pass through to its shareholders a tax credit or deduction passed through by a Fund.

In addition, a Fund’s investments in foreign securities, fixed income securities, derivatives, or foreign currencies may increase or accelerate the Fund’s recognition of ordinary income and may affect the timing, amount, or character of the Fund’s distributions.

Certain of a Fund’s investments, including certain debt instruments, could cause the Fund to recognize taxable income in excess of the cash generated by such investments; a Fund could be required to sell other investments, including when not otherwise advantageous to do so, in order to make required distributions.

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Distributions by a Fund to shareholders that are not “United States persons” within the meaning of the Code (“foreign persons”) properly reported by the Fund as (i) capital gain dividends, (ii) “interest-related dividends” (i.e., U.S.-source interest income that, in general, would not be subject to U.S. federal income tax if earned directly by an individual foreign shareholder), and (iii) “short-term capital gain dividends” (i.e., net short-term capital gains in excess of net long-term capital losses), in each case to the extent such distributions were properly reported as such by the Fund generally are not subject to withholding of U.S. federal income tax. Distributions by a Fund to foreign persons other than capital gain dividends, interest-related dividends, and short-term capital gain dividends generally are subject to withholding of U.S. federal income tax at a rate of 30% (or lower applicable treaty rate). Foreign persons should refer to the SAI for further information, and

should consult their tax advisors as to the tax consequences to them of owning Fund shares.

In order to qualify for the special tax treatment accorded regulated investment companies and their shareholders, a Fund must, among other things, derive at least 90% of its gross income from certain specified sources (such income, “qualifying income”). Direct investment in commodities and certain commodities-related investments generally do not, under published IRS guidance, produce qualifying income.

The discussion above is very general. Shareholders should consult their tax advisers for more information about the effect that an investment in a Fund could have on their own tax situations, including possible U.S. federal, state, local, and foreign taxes. Also, as noted above, this discussion does not apply to Fund shares held through tax-advantaged retirement plans.

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Financial Highlights

The financial highlights tables are intended to help you understand the Funds’ financial performance for the past 5 years (or shorter periods for newer Funds). Certain information reflects financial results for a single Fund share. The total returns in the tables represent the rate that an investor would have earned on an investment in the Fund (assuming reinvestment of all dividends and distributions). This information has been audited by Deloitte & Touche LLP, an independent registered public accounting firm, whose reports, along with each Fund’s financial statements, are included in the Trust’s Annual Reports, and are incorporated by reference into the SAI, and are available upon request.

MM EQUITY ASSET FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	7.00	$	0.09	$	1.39		$	1.48		$	(0.10	)	$	(0.96	)	$	(1.06	)	$	7.42		22.81	%	$	282,977		0.28	%		N/A			1.26	%
9/30/22		10.12		0.10		(1.05	)		(0.95	)		(0.13	)		(2.04	)		(2.17	)		7.00		(14.16	%)		303,274		0.23	%		N/A			1.20	%
9/30/21		8.79		0.11		2.38			2.49			(0.14	)		(1.02	)		(1.16	)		10.12		30.90	%		397,810		0.22	%		N/A			1.20	%
9/30/20		7.90		0.12		1.25			1.37			(0.11	)		(0.37	)		(0.48	)		8.79		17.91	%		423,084		0.24	%		N/A			1.48	%
9/30/19		12.36		0.12		(0.49	)^aa		(0.37	)		(0.50	)		(3.59	)		(4.09	)		7.90		3.10	%		489,569		0.24	%		0.21	%		1.48	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	27%	39%	29%	60%	49%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

aa	The amount shown for a share outstanding does not correspond with the aggregate net realized and unrealized gain (loss) for the period due to the timing of purchases and redemptions of Fund shares in relation to the fluctuating market values of the Fund.

– 84 –

MASSMUTUAL SELECT T. ROWE PRICE BOND ASSET FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	8.63	$	0.31	$	(0.15	)	$	0.16		$	(0.54	)	$	—		$	(0.54	)	$	8.25		1.75	%	$	593,579		0.11	%		0.00	%		3.70	%
9/30/22		10.43		0.21		(1.67	)		(1.46	)		(0.31	)		(0.03	)		(0.34	)		8.63		(14.50	%)		558,491		0.08	%		0.00	%		2.19	%
9/30/21		10.65		0.20		(0.07	)		0.13			(0.16	)		(0.19	)		(0.35	)		10.43		1.26	%		814,111		0.07	%		0.00	%		1.89	%
9/30/20		10.59		0.24		0.18			0.42			(0.31	)		(0.05	)		(0.36	)		10.65		4.15	%		750,915		0.45	%		0.33	%		2.32	%
9/30/19		9.94		0.29		0.69			0.98			(0.33	)		—			(0.33	)		10.59		10.21	%		670,362		0.56	%		0.40	%		2.90	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	265%	290%	255%	157%	287%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

– 85 –

MASSMUTUAL SELECT T. ROWE PRICE EMERGING MARKETS BOND FUND

			Income (loss) from investment operations								Less distributions to shareholders													Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains		Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	6.81	$	0.53	$	0.38		$	0.91		$	(0.45	)	$	—	$	(0.45	)	$	7.27		13.45	%	$	78,121		0.25	%		0.00	%		7.27	%
9/30/22		9.73		0.44		(2.82	)		(2.38	)		(0.54	)		—		(0.54	)		6.81		(25.84	%)		75,893		0.19	%		0.00	%		5.29	%
9/30/21		9.50		0.51		0.31			0.82			(0.59	)		—		(0.59	)		9.73		8.74	%		107,177		0.17	%		0.00	%		5.29	%
9/30/20		9.91		0.50		(0.41	)		0.09			(0.50	)		—		(0.50	)		9.50		0.88	%		109,979		0.76	%		0.58	%		5.29	%
9/30/19		9.64		0.53		0.06			0.59			(0.32	)		—		(0.32	)		9.91		6.35	%		110,630		0.92	%		0.70	%		5.45	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	28%	37%	49%	56%	39%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

– 86 –

MASSMUTUAL SELECT T. ROWE PRICE LARGE CAP BLEND FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	11.23	$	0.16	$	2.11		$	2.27		$	(0.10	)	$	(1.17	)	$	(1.27	)	$	12.23		21.41	%	$	2,175,818		0.03	%		0.00	%		1.37	%
9/30/22		17.43		0.16		(3.36	)		(3.20	)		(0.15	)		(2.85	)		(3.00	)		11.23		(22.96	%)		1,853,860		0.02	%		0.00	%		1.13	%
9/30/21		13.00		0.16		4.39			4.55			(0.12	)		—			(0.12	)		17.43		35.17	%		2,309,626		0.02	%		0.00	%		0.97	%
9/30/20		11.36		0.11		1.65			1.76			(0.12	)		—			(0.12	)		13.00		15.60	%		1,772,717		0.51	%		0.44	%		0.91	%
9/30/19		10.87		0.12		0.45			0.57			(0.08	)		—			(0.08	)		11.36		5.39	%		1,280,663		0.65	%		0.56	%		1.09	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	73%	121%	65%	90%	67%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

– 87 –

MASSMUTUAL SELECT T. ROWE PRICE LIMITED DURATION INFLATION FOCUSED BOND FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	9.85	$	0.36	$	(0.18	)	$	0.18		$	(0.94	)	$	—		$	(0.94	)	$	9.09		1.86	%	$	202,453		0.10	%		0.00	%		3.88	%
9/30/22		11.02		0.63		(1.13	)		(0.50	)		(0.53	)		(0.14	)		(0.67	)		9.85		(4.82	%)		189,897		0.07	%		0.00	%		5.97	%
9/30/21		10.64		0.42		0.30			0.72			(0.19	)		(0.15	)		(0.34	)		11.02		6.96	%		272,860		0.07	%		0.00	%		3.93	%
9/30/20		10.27		0.15		0.41			0.56			(0.19	)		(0.00	)^d		(0.19	)		10.64		5.58	%		186,441		0.37	%		0.13	%		1.48	%
9/30/19		10.09		0.25		0.14			0.39			(0.21	)		—			(0.21	)		10.27		3.95	%		199,074		0.44	%		0.16	%		2.50	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	153%	176%	193%	156%	135%

c	Per share amount calculated on the average shares method.

d	Amount is less than $0.005 per share.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

– 88 –

MASSMUTUAL SELECT T. ROWE PRICE REAL ASSETS FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	10.34	$	0.34	$	0.90		$	1.24		$	(0.33	)	$	(0.56	)	$	(0.89	)	$	10.69		11.61	%	$	325,608		0.13	%		0.00	%		3.09	%
9/30/22		12.85		0.49		(1.86	)		(1.37	)		(0.36	)		(0.78	)		(1.14	)		10.34		(12.24	%)		210,339		0.09	%		0.00	%		3.93	%
9/30/21		9.83		0.37		2.89			3.26			(0.24	)		—			(0.24	)		12.85		33.66	%		162,367		0.13	%		0.00	%		3.04	%
9/30/20		10.49		0.23		(0.60	)		(0.37	)		(0.29	)		—			(0.29	)		9.83		(3.77	%)		99,585		0.69	%		0.50	%		2.33	%
9/30/19		10.56		0.27		(0.16	)		0.11			(0.18	)		—			(0.18	)		10.49		1.26	%		82,224		0.86	%		0.61	%		2.60	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	61%	43%	57%	32%	40%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

– 89 –

MASSMUTUAL SELECT T. ROWE PRICE SMALL AND MID CAP BLEND FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	11.01	$	0.15	$	1.32		$	1.47		$	(0.10	)	$	(0.79	)	$	(0.89	)	$	11.59		13.50	%	$	729,155		0.06	%		0.00	%		1.29	%
9/30/22		16.20		0.14		(3.18	)		(3.04	)		(0.16	)		(1.99	)		(2.15	)		11.01		(21.64	%)		665,939		0.03	%		0.00	%		1.04	%
9/30/21		12.41		0.15		4.43			4.58			(0.10	)		(0.69	)		(0.79	)		16.20		37.99	%		910,874		0.04	%		0.00	%		0.97	%
9/30/20		11.44		0.07		1.18			1.25			(0.07	)		(0.21	)		(0.28	)		12.41		10.97	%		747,318		0.61	%		0.53	%		0.58	%
9/30/19		11.47		0.07		0.09			0.16			(0.04	)		(0.15	)		(0.19	)		11.44		1.72	%		632,662		0.76	%		0.65	%		0.59	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	39%	34%	28%	41%	33%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

– 90 –

MASSMUTUAL SELECT T. ROWE PRICE U.S. TREASURY LONG-TERM INDEX FUND

			Income (loss) from investment operations								Less distributions to shareholders														Ratios / Supplemental Data
	Net asset value, beginning of the period		Net investment income (loss)^c,j		Net realized and unrealized gain (loss) on investments			Total income (loss) from investment operations			From net investment income			From net realized gains			Total distributions			Net asset value, end of the period		Total return^l,m			Net assets, end of the period (000)’s		Ratio of expenses to average daily net assets before expense waivers			Ratio of expenses to average daily net assets after expense waivers^j			Net investment income (loss) to average daily net assets
Class I
9/30/23	$	5.47	$	0.18	$	(0.71	)	$	(0.53	)	$	(0.13	)	$	—		$	(0.13	)	$	4.81		(9.99	%)	$	142,850		0.12	%		0.00	%		3.29	%
9/30/22		7.62		0.15		(2.17	)		(2.02	)		(0.13	)		—			(0.13	)		5.47		(26.97	%)		126,709		0.11	%		0.00	%		2.29	%
9/30/21		13.07		0.14		(1.17	)		(1.03	)		(0.16	)		(4.26	)		(4.42	)		7.62		(10.55	%)		109,251		0.15	%		0.00	%		1.69	%
9/30/20		12.25		0.25		1.45			1.70			(0.31	)		(0.57	)		(0.88	)		13.07		15.26	%		67,408		0.42	%		0.13	%		2.07	%
9/30/19		10.03		0.30		2.12			2.42			(0.20	)		—			(0.20	)		12.25		24.53	%		153,801		0.43	%		0.16	%		2.74	%

	Year ended September 30
	2023	2022	2021	2020	2019
Portfolio turnover rate	123%	102%	116%	206%	155%

c	Per share amount calculated on the average shares method.

j	Computed after giving effect to an agreement by MML Advisers to waive certain fees and expenses of the Fund.

l	Employee retirement benefit plans that invest plan assets in the Separate Investment Accounts (SIAs) may be subject to certain charges as set forth in their respective Plan Documents. Total return figures would be lower for the periods presented if they reflected these charges.

m	Total return excludes sales charges, if any, and would be lower for the period presented if it reflected these charges.

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Index Descriptions

The Bloomberg Emerging Markets Hard Currency (USD) Aggregate Index measures the performance of USD, EUR, and GBP-denominated debt from sovereign, quasi-sovereign, and corporate Emerging Markets issuers. Country eligibility and classification as Emerging Markets is rules-based and reviewed annually using the World Bank income group and International Monetary Fund country classifications. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The Bloomberg U.S. Aggregate Bond Index measures the performance of investment grade, U.S. dollar-denominated, fixed-rate taxable bond market securities, including Treasuries, government-related and corporate securities, mortgage-backed securities (MBS) (agency fixed-rate and hybrid ARM pass-throughs), asset-backed securities (ABS), and commercial mortgage-backed securities (CMBS). It rolls up into other Bloomberg flagship indexes, such as the multi-currency Global Aggregate Index and the U.S. Universal Index, which includes high yield and emerging markets debt. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The Bloomberg U.S. 1-5 Year Treasury TIPS Index measures the performance of inflation-protected securities with maturities of 1-5 years issued by the U.S. Treasury. It is a subset of the Global Inflation-Linked Index (Series-L), with a 38.5% market value weight in the Index (as of December 31, 2010), but is not eligible for other nominal Treasury or Aggregate Indexes. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The Bloomberg U.S. Long Treasury Bond Index measures the performance of public obligations of the U.S. Treasury with maturities of 10 years and greater, including securities that roll up to the U.S. Aggregate, U.S. Universal, and Global Aggregate Indexes. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The J.P. Morgan Emerging Markets Bond Index Global Diversified measures the performance of fixed rate, U.S. dollar-denominated debt instruments issued by emerging market sovereign and quasi-sovereign entities, including Brady bonds, loans, and Eurobonds. The Index limits the weights of those index countries with larger debt stocks by only including a specified portion of a country’s eligible amounts of debt outstanding. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The MSCI All Country World Index (ACWI) measures the performance of the large- and mid-cap segments of all country markets. It is free float-adjusted market-capitalization weighted. The Index does not reflect any deduction for fees or expenses and cannot be purchased directly by investors.

The Russell 1000 Index measures the performance of the large-cap segment of U.S. equity securities. It is a subset of the Russell 3000® Index and includes approximately 1000 of the largest securities based on a combination of their market cap and current index membership. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The Russell 2500 Index measures the performance of the small to mid-cap segment of the US equity universe. It is a subset of the Russell 3000 Index and includes approximately 2500 of the smallest securities based on the combination of their market cap and current index membership. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

The S&P 500 Index measures the performance of 500 widely held stocks in the U.S. equity market. Standard and Poor’s chooses member companies for the index based on market size, liquidity, and industry group representation. Included are the stocks of industrial, financial, utility, and transportation companies. Since mid-1989, this composition has been more flexible and the number of issues in each sector has varied. It is market capitalization-weighted. The Index does not reflect any deduction for fees, expenses, or taxes and cannot be purchased directly by investors.

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MassMutual Funds

1295 State Street

Springfield, Massachusetts 01111-0001

Learning More About the Funds

You can learn more about the Funds by reading the Funds’ Annual and Semiannual Reports and the SAI. You may obtain free copies of this information from the Funds or from the SEC using one or more of the methods set forth below. In the Annual and Semiannual Reports, you will find a discussion of market conditions and investment strategies that significantly affected each Fund’s performance during the period covered by the Report and a listing of each Fund’s portfolio securities as of the end of such period. The SAI provides additional information about the Funds and will provide you with more detail regarding the organization and operation of the Funds, including their investment strategies. The SAI is incorporated by reference into this Prospectus and is therefore legally considered a part of this Prospectus.

How to Obtain Information

From the Funds:

You may request information about the Funds free of charge (including the Annual/Semiannual Reports and the SAI) or make shareholder inquiries by calling 1-888-309-3539 or by writing the Funds, c/o Massachusetts Mutual Life Insurance Company, 1295 State Street, Springfield, Massachusetts 01111-0001, Attention: Investment Management Solutions. You may also obtain copies of the Annual/Semiannual Reports and the SAI free of charge at https://www.massmutual.com/funds.

From the SEC:

Information about the Funds (including the Annual/Semiannual Reports and the SAI) is available on the SEC’s EDGAR database on its Internet site at http://www.sec.gov. You can also get copies of this information, upon payment of a copying fee, by electronic request at [email protected].

When obtaining information about the Funds from the SEC, you may find it useful to reference the

Funds’ SEC file number: 811-8274.