Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the accuracy or adequacy of this Prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

MainStay CBRE Specialty Funds

MainStay CBRE Global Infrastructure Fund	3
MainStay CBRE Real Estate Fund	10
More About Investment Strategies and Risks	16
Shareholder Guide	30
Know With Whom You Are Investing	72
Financial Highlights	75
Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts	87

1.  No initial sales charge applies on investments of $1 million or more (and certain other qualified purchases). However, a contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge.

2. The management fee is as follows: 0.85% on assets up to $3 billion and 0.84% on assets over $3 billion.

3. New York Life Investment Management LLC ("New York Life Investments") has contractually agreed to waive fees and/or reimburse expenses so that Total Annual Fund Operating Expenses (excluding taxes, interest, litigation, extraordinary expenses, brokerage and other transaction expenses relating to the purchase or sale of portfolio investments, and acquired (underlying) fund fees and expenses) do not exceed the following percentages of its average daily net assets: Class A, 1.33%; Investor Class, 1.45%; Class C, 2.08%; Class I, 0.97%; and Class R6, 0.95%. This agreement will remain in effect until August 31, 2024, and thereafter shall renew automatically for one-year terms unless New York Life Investments provides written notice of termination prior to the start of the next term or upon approval of the Board of Trustees of the Fund.

The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated whether or not you redeem all of your shares at the end of those periods (except as indicated with respect to Class C shares). The Example reflects Class C shares converting into Investor Class shares in years 9-10; expenses could be lower if you are eligible to convert to Class A shares instead. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the contractual fee waiver and/or expense reimbursement arrangement, if applicable, for the current duration of the arrangement only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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MainStay CBRE Global Infrastructure Fund

7

MainStay CBRE Global Infrastructure Fund

1.  The FTSE Global Core Infrastructure 50/50 Index (Net) is a market-capitalization-weighted index of worldwide infrastructure and infrastructure-related securities. Constituent weights are adjusted semi-annually according to three broad industry sectors: 50% utilities, 30% transportation, and a 20% mix of other sectors.

After-tax returns are calculated using the highest individual federal marginal income tax rates in effect at the time of each distribution or capital gain or upon the sale of Fund shares, and do not reflect the impact of state and local taxes. In some cases, the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of shares at the end of the measurement period. Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns are not relevant if you hold your shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns shown are for Class A shares. After-tax returns for the other share classes may vary.

New York Life Investment Management LLC serves as the Manager. CBRE Investment Management Listed Real Assets LLC serves as the Subadvisor. The individuals listed below are jointly and primarily responsible for day-to-day portfolio management.

You may purchase or sell shares of the Fund on any day the Fund is open for business by contacting your financial adviser or financial intermediary firm, or by contacting the Fund by telephone at 800-624-6782, by mail at MainStay Funds, P.O. Box 219003, Kansas City, MO 64121-9000, by overnight mail to 430 West 7^th Street, Suite 219003, Kansas City, MO 64105-1407, or by accessing our website at newyorklifeinvestments.com/accounts. Class R6 shares are generally only available to certain retirement plans invested in the Fund through omnibus accounts (either at the plan level or omnibus accounts held on the books of the Fund). Class R6 shares are generally not available to retail accounts. Generally, an initial investment minimum of $1,000 applies if you invest in Investor Class or Class C shares, $15,000 for Class A shares and $1,000,000 for individual investors in Class I shares investing directly (i) with the Fund; or (ii) through certain private banks and trust companies that have an agreement with NYLIFE Distributors LLC, the Fund’s principal underwriter and distributor, or its affiliates. A subsequent investment minimum of $50 applies to investments in Investor Class and Class C shares. However, for Investor Class and Class C shares purchased through AutoInvest, MainStay’s systematic investment plan, a $500 initial investment minimum and a $50 minimum for subsequent purchases applies. Class A shares have no subsequent investment minimum. Class R6 shares and institutional shareholders in Class I shares have no initial or subsequent investment minimums.

Certain financial intermediaries through whom you may invest may impose their own investment minimums, fees, policies and procedures for purchasing and selling Fund shares, which are not described in this Prospectus or the Statement of Additional Information, and which will depend on the policies, procedures and trading platforms of the financial intermediary. Consult a representative of your financial intermediary about the availability of shares of the Fund and the intermediary's policies, procedures and other information.

The Fund's distributions are generally taxable to you as ordinary income, capital gains, or a combination of the two, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account.

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MainStay CBRE Global Infrastructure Fund

If you purchase Fund shares through a financial intermediary firm (such as a broker/dealer or bank), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the financial intermediary firm or your financial adviser to recommend the Fund over another investment. Ask your financial adviser or visit your financial intermediary firm's website for more information. No compensation, administrative payments, sub-transfer agency payments or service payments are paid to broker/dealers or other financial intermediaries from Fund assets or the Distributor’s or an affiliate’s resources on sales of or investments in Class R6 shares. The Distributor or an affiliate may pay de minimis amounts to intermediaries for setup, connectivity or other technological expenses. Class R6 shares do not carry sales charges or pay Rule 12b-1 fees, or make payments to financial intermediaries to assist in, or in connection with, the sale of the Fund’s shares.

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MainStay CBRE Real Estate Fund

1.  No initial sales charge applies on investments of $1 million or more (and certain other qualified purchases). However, a contingent deferred sales charge of 1.00% may be imposed on certain redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge.

2. New York Life Investment Management LLC ("New York Life Investments") has contractually agreed to waive fees and/or reimburse expenses so that Total Annual Fund Operating Expenses (excluding taxes, interest, litigation, extraordinary expenses, brokerage and other transaction expenses relating to the purchase or sale of portfolio investments, and acquired (underlying) fund fees and expenses) do not exceed the following percentages of its average daily net assets: Class A, 1.18%; Investor Class 1.35%; Class C, 1.93%; Class I, 0.83%; Class R3, 1.43%; and Class R6, 0.74%. This agreement will remain in effect until August 31, 2024, and thereafter shall renew automatically for one-year terms unless New York Life Investments provides written notice of termination prior to the start of the next term or upon approval of the Board of Trustees of the Fund.

The Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Fund for the time periods indicated whether or not you redeem all of your shares at the end of those periods (except as indicated with respect to Class C shares). The Example reflects Class C shares converting into Investor Class shares in years 9-10; expenses could be lower if you are eligible to convert to Class A shares instead. The Example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The Example reflects the contractual fee waiver and/or expense reimbursement arrangement, if applicable, for the current duration of the arrangement only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

10

MainStay CBRE Real Estate Fund

13

MainStay CBRE Real Estate Fund

1.  The FTSE Nareit All Equity REITs Index is a free-float adjusted, market capitalization-weighted index of U.S. equity REITs. Constituents of the index include all tax-qualified REITs with more than 50 percent of total assets in qualifying real estate assets other than mortgages secured by real property.

2.  The returns for the CBRE Real Estate Tiered Index represent the returns of the MSCI U.S. REIT^® Index prior to January 1, 2021 and the returns of the FTSE Nareit All Equity REITs Index thereafter.

3.  The MSCI U.S. REIT^® Index is a free float-adjusted market capitalization weighted index that is comprised of equity REITs. The MSCI U.S. REIT^® Index is based on the MSCI USA Investable Market Index, its parent index, which captures the large, mid and small cap segments of the U.S. market.

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MainStay CBRE Real Estate Fund

After-tax returns are calculated using the highest individual federal marginal income tax rates in effect at the time of each distribution or capital gain or upon the sale of Fund shares, and do not reflect the impact of state and local taxes. In some cases, the return after taxes may exceed the return before taxes due to an assumed tax benefit from any losses on a sale of shares at the end of the measurement period. Actual after-tax returns depend on your tax situation and may differ from those shown. After-tax returns are not relevant if you hold your shares through tax-deferred arrangements, such as 401(k) plans or individual retirement accounts. After-tax returns shown are for Class A shares. After-tax returns for the other share classes may vary.

New York Life Investment Management LLC serves as the Manager. CBRE Investment Management Listed Real Assets LLC serves as the Subadvisor. The individuals listed below are jointly and primarily responsible for day-to-day portfolio management.

You may purchase or sell shares of the Fund on any day the Fund is open for business by contacting your financial adviser or financial intermediary firm, or by contacting the Fund by telephone at 800-624-6782, by mail at MainStay Funds, P.O. Box 219003, Kansas City, MO 64121-9000, by overnight mail to 430 West 7^th Street, Suite 219003, Kansas City, MO 64105-1407, or by accessing our website at newyorklifeinvestments.com/accounts.

Class R6 shares are generally available only to certain retirement plans invested in the Fund through omnibus accounts (either at the plan level or omnibus accounts held on the books of the Fund). Class R6 shares are generally not available to retail accounts. Generally, an initial investment minimum of $1,000 applies if you invest in Investor Class or Class C shares, $15,000 for Class A shares and $1,000,000 for individual investors in Class I shares investing directly (i) with the Fund; or (ii) through certain private banks and trust companies that have an agreement with NYLIFE Distributors LLC, the Fund’s principal underwriter and distributor, or its affiliates. A subsequent investment minimum of $50 applies to investments in Investor Class and Class C shares. However, for Investor Class and Class C shares purchased through AutoInvest, MainStay’s systematic investment plan, a $500 initial investment minimum and a $50 minimum for subsequent purchases applies. Class A shares have no subsequent investment minimum. Class R3 shares, Class R6 shares and institutional shareholders in Class I shares have no initial or subsequent investment minimums.

Certain financial intermediaries through whom you may invest may impose their own investment minimums, fees, policies and procedures for purchasing and selling Fund shares, which are not described in this Prospectus or the Statement of Additional Information, and which will depend on the policies, procedures and trading platforms of the financial intermediary. Consult a representative of your financial intermediary about the availability of shares of the Fund and the intermediary's policies, procedures and other information.

The Fund's distributions are generally taxable to you as ordinary income, capital gains, or a combination of the two, unless you are investing through a tax-deferred arrangement, such as a 401(k) plan or an individual retirement account.

If you purchase Fund shares through a financial intermediary firm (such as a broker/dealer or bank), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the financial intermediary firm or your financial adviser to recommend the Fund over another investment. Ask your financial adviser or visit your financial intermediary firm's website for more information. No compensation, administrative payments, sub-transfer agency payments or service payments are paid to broker/dealers or other financial intermediaries from Fund assets or the Distributor’s or an affiliate’s resources on sales of or investments in Class R6 shares. The Distributor or an affiliate may pay de minimis amounts to intermediaries for setup, connectivity or other technological expenses. Class R6 shares do not carry sales charges or pay Rule 12b-1 fees, or make payments to financial intermediaries to assist in, or in connection with, the sale of the Fund’s shares.

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More About Investment Strategies and Risks

Investment Policies and Objectives

The Funds have names which suggest a focus on a particular type of investment. In accordance with Rule 35d-1 under the 1940 Act, each of these Funds has adopted a policy that it will, under normal circumstances, invest at least 80% of the value of its assets (net assets plus the amount of any borrowings for investment purposes) in investments of the type suggested by its name, as set forth in the Statement of Additional Information. This requirement is applied at the time a Fund invests its assets. If, subsequent to an investment by a Fund, this requirement is no longer met, the Fund's future investments will be made in a manner that will bring the Fund into compliance with this requirement. To the extent a Fund invests in derivatives, such investments may be counted on a mark-to-market basis for purposes of the 80% policy. In addition, in appropriate circumstances, synthetic investments may count toward the 80% policy if they have economic characteristics similar to the other investments included in the basket. With respect to the Funds, a Fund’s policy to invest at least 80% of its assets in such a manner is “non-fundamental,” which means that it may be changed without the approval of a “majority of the outstanding voting securities” of the Fund, as defined in the 1940 Act. The Funds have adopted a policy to provide each Fund's shareholders with at least 60 days' prior notice of any change in the Fund’s non-fundamental investment policy with respect to investments of the type suggested by its name. For additional information, please see the SAI.

When the discussion states that the MainStay CBRE Global Infrastructure Fund invests "primarily" in a certain type or style of investment, this means that under normal circumstances the MainStay CBRE Global Infrastructure Fund will invest at least 65% of its assets, as described above, in that type or style of investment.

The Funds may invest their net assets in other investment companies, including exchange-traded funds that invest in similar securities to those in which the Fund may invest directly, and count such holdings towards various guideline tests (such as the 80% test required under Rule 35d-1 under the 1940 Act).

Each Fund’s investment objective is non-fundamental and may be changed without shareholder approval.

Russian Securities

Until further notice, each Fund will not purchase securities of Russian issuers.

Additional Information About Risks

The principal risks of investing in the Funds are described below, which may result in a loss of your investment. As indicated in the table below, not all of these risks are principal risks of investing in each Fund. The risks are presented below in alphabetical order, and not in the order of importance or potential exposure. Each Fund may be subject to risks to different degrees. The fact that a particular risk is not identified as a principal risk for a Fund does not mean that the Fund is prohibited from investing in securities or investments that give rise to that risk. There can be no assurance that a Fund will achieve its investment objective.

Investors should be aware that in light of the current uncertainty, volatility and state of economies, financial markets, and labor and health conditions around the world, the risks below are heightened significantly compared to normal conditions and therefore may subject a Fund's investments and a shareholder’s investment in a Fund to reduced yield and/or income and sudden and substantial losses. The fact that a particular risk below is not specifically identified as being heightened under current conditions does not mean that the risk is not greater than under normal conditions.

Additional information about the investment practices of the Funds and risks pertinent to these practices is included in the SAI. The following information regarding principal investment strategies and risks is provided in alphabetical order and not necessarily in order of importance.

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More About Investment Strategies and Risks

Closed-End Funds

Closed-end funds are investment companies that generally do not continuously offer their shares for sale. Rather, closed-end funds typically trade on a secondary market, such as the New York Stock Exchange (“Exchange”) or the NASDAQ Stock Market, Inc. ("NASDAQ"). Listed closed-end funds are subject to management risk because the adviser to the closed-end fund may be unsuccessful in meeting the closed-end fund’s investment objective. Moreover, investments in a closed-end fund generally reflect the risks of the closed-end fund's underlying portfolio of securities. Closed-end funds may also trade at a discount or premium to their NAV and may trade at a larger discount or smaller premium subsequent to their purchase. Closed-end funds may trade infrequently and with small

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More About Investment Strategies and Risks

volume, which may make it difficult to buy and sell shares. Closed-end funds are subject to management fees and other expenses that may increase their cost versus the costs of directly owning the underlying securities. Since closed-end funds may trade on exchanges, a Fund may also incur brokerage expenses and commissions when it buys or sells closed-end fund shares.

Concentration Risk

Because the Funds focus their investments in a specific industry or group of industries, the Funds may be subject to greater risks and market fluctuations than a fund whose portfolio has exposure to a broader range of industries. The Funds are particularly susceptible to financial, economic, political, or market events, as well as government regulation, impacting the industries in which they invest. The Funds are subject to the risk that: (1) their performance will be closely tied to the performance of those particular industries; (2) their performance will be adversely impacted when such industries experience a downturn; and (3) they will perform poorly during a slump in demand for securities of companies in such industries. Securities of issuers in certain industries are at times volatile, and there may be sharp fluctuations in prices, even during periods of rising prices. To the extent that the Subadvisor’s expectations regarding developments in industries in which a Fund invests are not realized, the Fund may underperform securities markets generally and more broadly diversified funds.

Convertible Securities

Convertible securities, until converted, have the same general characteristics as debt securities insofar as they generally provide a stable stream of income with generally higher yields than those of equity securities of the same or similar issuers. By permitting the holder to exchange an investment for common stock or the cash value of a security or a basket or index of securities, convertible securities may also enable the investor to benefit from increases in the market price of the underlying securities. Therefore, convertible securities generally offer lower interest or dividend yields than non-convertible securities of similar quality.

Depositary Receipts

American Depositary Receipts ("ADRs"), European Depositary Receipts ("EDRs"), Global Depositary Receipts ("GDRs"), International Depositary Receipts ("IDRs"), Non-Voting Depositary Receipts (“NVDRs”) and other similar securities represent ownership of securities of non-U.S. issuers held in trust by a bank, exchange or similar financial institution. ADRs are denominated in U.S. dollars and trade in the U.S. securities markets. GDRs and EDRs are receipts issued by foreign banks or trust companies, or foreign branches of U.S. banks that represent an interest in shares of either a foreign or U.S. corporation. NVDRs are typically issued by an exchange or its affiliate and do not have voting rights. These investments may not be denominated in the same currency as the underlying securities into which they may be converted, and are subject to currency risks. Depositary receipts involve many of the same risks of investing directly in foreign securities. The issuers of depositary receipts may discontinue issuing new depositary receipts and withdraw existing depositary receipts at any time, which may result in costs and delays in the distribution of the underlying assets to a Fund and may negatively impact the Fund’s performance.

Derivative Transactions Risk

Derivative transactions, or “derivatives,” may include options, forwards, futures, options on futures and swap agreements. The value of derivatives is based on certain underlying equity or fixed-income securities, interest rates, currencies, commodities or indices. The use of these transactions is a highly specialized activity that involves investment techniques, tax planning and risks that are different from those of ordinary securities transactions. Derivatives may be difficult to sell at an advantageous price or time and typically are very sensitive to changes in the underlying security, interest rate, currency, commodity or index. As a result, derivatives can be highly volatile. If the Manager or the Subadvisor is incorrect about its expectations of changes to the underlying securities, interest rates, currencies, commodities, indices or market conditions, the use of derivatives could result in a loss, which in some cases may be unlimited. When using over-the-counter (“OTC”) or bilateral derivatives, there is a risk that a Fund will lose money if the contract counterparty does not make the required payments or otherwise fails to comply with the terms of the contract. OTC derivatives are complex and often valued subjectively, which exposes a Fund to heightened liquidity risk, mispricing and valuation risk. In the event of the bankruptcy or insolvency of a counterparty, a Fund could experience the loss of some or all of its investment in a derivative or experience delays in liquidating its positions, including declines in the value of its investment during the period in which a Fund seeks to enforce its rights, and an inability to realize any gains on its investment during such period. A Fund may also incur fees and expenses in enforcing its rights. Certain derivatives are subject to mandatory clearing and exchange-trading. Central clearing, which interposes a central clearinghouse to each participant’s derivatives position, is intended to reduce counterparty credit risk and exchange-trading is intended to increase liquidity, but neither make derivatives transactions risk-free.

In addition, certain derivative transactions can result in leverage. Leverage involves investment exposure in an amount exceeding the initial investment. Leverage can cause increased volatility by magnifying gains or losses. Investments in derivatives may increase or accelerate the amount of taxable income, or result in the deferral of losses, that would otherwise be recognized by a Fund in determining the amount of dividends distributable to shareholders.

Trading of derivatives and other transactions that create future payment or delivery obligations (except reverse repurchase agreements and similar financing transactions) is subject to a limit on notional derivatives exposure as a limited derivatives user or subject to a value-at-risk leverage limit and certain derivatives risk management program and reporting requirements. These requirements may limit the ability of a Fund to invest in derivatives, short sales and similar financing transactions, limit a Fund's ability to employ certain strategies

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that use these instruments and/or adversely affect a Fund's efficiency in implementing its strategy, liquidity and/or ability to pursue its investment objectives.

Future regulatory developments may impact a Fund's ability to invest or remain invested in certain derivatives. Legislation or regulation may also change the way in which a Fund itself is regulated. These or other legislative or regulatory changes may negatively impact a Fund and/or result in a change in its investment strategy.

Dividend-Paying Stocks

Dividend-paying stocks may underperform the securities of other companies that do not typically produce income or other distributions. In addition, issuers of dividend-paying stock may have discretion at any time to reduce, defer, or stop paying dividends for a stated period of time. Depending upon market conditions, an income-producing stock that meets a Fund’s investment criteria may not be widely available and/or may be highly concentrated in only a few market sectors. This may limit the ability of a Fund to produce current income while remaining fully diversified. The distributions received by a Fund may not qualify as income for Fund investors.

Emerging Markets

The risks of foreign investments (or exposure to foreign investments) are usually much greater when they are made in (or result in exposure to) emerging markets. Investments in emerging markets may be considered speculative. Emerging markets are riskier than more developed markets because they tend to develop unevenly and may never fully develop. They are more likely to experience high rates of inflation and currency devaluations, which may adversely affect returns. In addition, many emerging markets have far lower trading volumes and less liquidity than developed markets. Since these markets are often small, they may be more likely to suffer sharp and frequent price changes or long-term price depression because of adverse publicity, investor perceptions or the actions of a few large investors. In addition, traditional measures of investment value used in the United States, such as price to earnings ratios, may not apply to certain emerging markets. Also, there may be less publicly available information about issuers in emerging markets than would be available about issuers in more developed capital markets, and such issuers may not be subject to accounting, auditing, recordkeeping and financial reporting standards and requirements comparable to those to which companies in developed countries are subject. Local exchanges in emerging market countries may also be likely to experience market manipulation by foreign nationals who possess inside information.

Many emerging markets have histories of political instability and abrupt changes in policies. As a result, their governments may be more likely to take actions that are hostile or detrimental to private enterprise or foreign investment than those of more developed countries, including expropriation of assets, confiscatory taxation or unfavorable diplomatic developments. Some emerging market countries have pervasive corruption and crime that may hinder investments. Certain emerging markets may also face other significant internal or external risks, including the risk of war, macroeconomic, geopolitical, global health conditions, and ethnic, religious and racial conflicts. In addition, governments in many emerging market countries participate to a significant degree in their economies and securities markets. Such government participation or other intervention may impair investment and economic growth or otherwise adversely affect investments in these countries or regions. National policies (including sanctions programs) that may limit investment opportunities include restrictions on investment in issuers or industries deemed sensitive to national interests.

Emerging markets may also have differing legal systems and the existence or possible imposition of exchange controls, custodial restrictions or other laws or restrictions applicable to investments differ from those found in more developed markets. Sometimes, they may lack, or be in the relatively early development of, legal systems, including structures governing private or foreign investment or allowing for judicial redress (such as limits on rights and remedies available to a Fund) for investment losses and injury to private property, and the ability of U.S. authorities (e.g., the Securities and Exchange Commission (“SEC”) and the U.S. Department of Justice) and investors (e.g., the Funds) to bring actions against bad actors may be limited. There may also be significant obstacles for investigations into or litigation against companies. As a result of these legal systems and limitations, a Fund faces the risk of being unable to enforce its rights with respect to its investments in emerging markets, which may cause losses to the Fund. In addition to withholding taxes on investment income, some emerging market countries may impose different capital gains taxes on foreign investors.

Practices in relation to settlement of securities transactions in emerging market countries involve higher risks than those in developed markets, 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. The possibility of fraud, negligence, undue influence being exerted by the issuer or refusal to recognize ownership exists in some emerging markets, and, along with other factors, could result in ownership registration being completely lost. A Fund would absorb any loss resulting from such registration problems and may have no successful claim for compensation. In addition, communications between parties in the United States and parties in emerging market countries may be unreliable, increasing the risk of delayed settlements or losses of security certificates.

Frontier market countries generally have smaller economies and even less developed capital markets than traditional emerging market countries (which themselves have increased investment risk relative to developed market countries), and, as a result, a Fund's exposure to the risks associated with investing in emerging market countries are magnified if the Fund invests in frontier market countries.

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Equity Securities Risk

Publicly held corporations may raise needed cash by issuing or selling equity securities to investors. When a Fund buys the equity securities of a corporation it becomes a part owner of the issuing corporation. Equity securities may be bought on domestic stock exchanges, foreign stock exchanges, or in the over-the-counter market. There are many different types of equity securities, including (without limitation) common stocks, preferred stocks, ADRs, and real estate investment trusts.

Investors buy equity securities to make money through dividend payments and/or selling them for more than they paid. The risks involved with investing in equity securities include (without limitation):

· Changing economic conditions: Equity securities may fluctuate as a result of general economic conditions, including changes in interest rates.

· Industry and company conditions: Certain industries or individual companies may come in and out of favor with investors. In addition, changing technology and competition may make the equity securities of a company or industry more volatile.

· Security selection: A portfolio manager may not be able to consistently select equity securities that appreciate in value, or anticipate changes that can adversely affect the value of a Fund's holdings. Investments in smaller and mid-size companies may be more volatile than investments in larger companies.

ESG Considerations

With respect to the Funds, CBRE Investment Management Listed Real Assets LLC, the Funds’ Subadvisor, may give consideration to ESG criteria when evaluating investment opportunities for a Fund, consistent with that Fund's investment objective and Principal Investment Strategies. The ESG criteria that may be used by the Subadvisor include, but are not limited to, climate resilience and risk management, decarbonization, energy and water resources and management, anti-discrimination policies, diversity and inclusion, community engagement, health and safety, human capital management, corporate governance, shareholder alignment, transparency, and compliance. The application of ESG criteria may result in a Fund (i) having exposure to certain securities or industry sectors that are different than the composition of the Fund's benchmark; and (ii) performing differently than the Fund's benchmark or other funds and strategies in the Fund's peer group that do not take into account ESG criteria or use different ESG criteria or ESG investment strategies. In addition, sectors and securities of companies that meet the ESG criteria may shift into and out of favor depending on market and economic conditions. The consideration of ESG criteria may adversely affect a Fund’s performance.

Exchange-Traded Funds (“ETFs”)

To the extent a Fund may invest in securities of other investment companies, it may invest in shares of ETFs, including ETFs advised by affiliates of New York Life Investments. ETFs are investment companies that trade like stocks. The price of an ETF is derived from and based upon the securities held by the ETF. However, like stocks, shares of ETFs are not traded at NAV, but may trade at prices above or below the value of their underlying portfolios. The level of risk involved in the purchase or sale of an ETF is similar to the risk involved in the purchase or sale of a traditional common stock, except that the pricing mechanism for an ETF is based on a basket of securities. Thus, the risks of owning an ETF generally reflect the risks of owning the underlying securities that the ETF is designed to track, although lack of liquidity in an ETF’s shares could result in the market price of the ETF’s shares being more volatile than the underlying portfolio of securities. Disruptions in the markets for the securities underlying ETFs could result in losses on investment in ETFs. In addition, an actual trading market may not develop for an ETF’s shares and the listing exchange may halt trading of an ETF’s shares. ETFs are subject to management fees and other fees that may increase their costs versus the costs of owning the underlying securities directly. A Fund will indirectly bear its proportionate share of management fees and other expenses that are charged by an ETF in addition to the management fees and other expenses paid by a Fund. A Fund will pay brokerage commissions in connection with the purchase and sale of shares of ETFs. A Fund may from time to time invest in ETFs, primarily as a means of gaining exposure for its portfolio to the market without investing in individual securities, particularly in the context of managing cash flows into the Fund or where access to a local market is restricted or not cost effective. In addition, an index-based ETF may not exactly replicate the performance of the index it seeks to track for a number of reasons, such as operating expenses, transaction costs and imperfect correlation between the performance of the ETF’s holdings and that of the index.

A Fund may invest in ETFs, among other reasons, to gain broad market, sector or asset class exposure, including during periods when it has large amounts of uninvested cash or when the Manager or Subadvisor believes share prices of ETFs offer attractive values, subject to any applicable investment restrictions in the Prospectus and the SAI.

Foreign Securities and Currencies

An issuer of a security is considered to be a U.S. or foreign issuer based on the issuer’s “country of risk” (or similar designation) as determined by a third party such as Bloomberg. The issuer’s “country of risk” is determined based on a number of criteria, which may change from time to time and currently include, but are not limited to, its country of domicile, the primary stock exchange on which it trades, the location from which the majority of its revenue comes, and its reporting currency. Although a Fund will generally rely on an issuer’s “country of risk,” as determined by Bloomberg when categorizing securities as either U.S. or foreign-based, it is not required to do so. Foreign securities may be more difficult to sell than U.S. securities. Foreign securities may be domiciled in the United States and traded on a U.S. market, but possess elements of foreign risk. Investments in foreign securities may involve difficulties in receiving or interpreting financial and economic information, possible imposition of taxes, higher brokerage and custodian fees, possible currency

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exchange controls or other government restrictions, including possible seizure or nationalization of foreign deposits or assets. Foreign securities may also be less liquid and more volatile than U.S. securities. Additionally, to the extent that the underlying securities held by the Fund trade on foreign exchanges or in foreign markets that may be closed when the U.S. markets are open, there are likely to be deviations between the current price of an underlying security and the last quoted price for the underlying security (i.e., the Fund's quote from the closed foreign market). There may also be difficulty in invoking legal protections across borders and, as a result, a Fund may have limited or no legal recourse with respect to foreign securities. In addition, investments in emerging market countries present unique and greater risks than those presented by investments in countries with developed securities markets and more advanced regulatory systems. For example, some Asia-Pacific countries can be characterized as emerging markets or newly industrialized and may experience more volatile economic cycles and less liquid markets than developed countries.  The Asia-Pacific region has historically been highly dependent on global trade and the growth, development and stability of the region can be adversely affected by, among other regional and global developments, trade barriers, exchange controls and other measures imposed or negotiated by the countries with which they trade. See “Emerging Markets” above.

Economic sanctions and other similar measures may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions or developments could, among other things, effectively restrict or eliminate the ability to purchase or sell certain foreign securities or groups of foreign securities, and thus may make investments in such securities less liquid or more difficult to value. Such sanctions may also cause a decline in the value of securities issued by the sanctioned country or companies located in or economically tied to the sanctioned country. In addition, as a result of economic sanctions and other similar governmental actions or developments, a Fund may be forced to sell or otherwise dispose of foreign investments at inopportune times or prices. Sanctions and other similar measures could significantly delay or prevent the settlement of securities transactions or their valuation, and significantly impact a Fund's liquidity and performance. Sanctions and other similar measures may be in place for a substantial period of time and enacted with limited advanced notice.

Many foreign securities are denominated or quoted in a foreign currency. A decline in value of a currency will have an adverse impact on the U.S. dollar value of any investments denominated in that currency. Exchange rate movements can be large and can endure for extended periods of time, affecting either favorably or unfavorably the value of a Fund's assets. However, a Fund may engage in foreign currency transactions to attempt to protect itself against fluctuations in currency exchange rates in relation to the U.S. dollar. See “Risk Management Techniques” below.

Changes in the value of foreign (non-U.S.) currencies relative to the U.S. dollar and inflation may adversely affect a Fund's investments in foreign currencies or in securities that trade in, and receive revenues in, or in derivatives that provide exposure to, foreign currencies. These changes in value can make the return on an investment go up or down, unrelated to the quality or performance of the investment itself. A Fund's manager or subadvisor may seek to reduce currency risk by hedging all or part of the exposure to various foreign currencies of a Fund's assets allocated to the Subadvisor by engaging in hedging transactions, including swaps, futures, forward currency contracts and other derivatives. However, these transactions and techniques may not always work as intended, and in certain cases a Fund may be worse off than if it had not engaged in such hedging practices. In addition, certain market conditions may make it impossible or uneconomical to hedge against currency risk.

Futures Transactions

Purchasing and selling single stock futures or stock index futures may be used to hedge the equity portion of its investment portfolio with regard to market (systemic) risk or to gain market exposure to that portion of the market represented by the futures contracts. A Fund may also purchase and sell other futures when deemed appropriate, in order to hedge the equity or non-equity portions of its portfolio. In addition, to the extent that it invests in foreign securities, and subject to any applicable restriction on its ability to invest in foreign currencies, a Fund may enter into contracts for the future delivery of foreign currencies to hedge against changes in currency exchange rates. Subject to compliance with applicable rules and restrictions, a Fund also may enter into futures contracts traded on foreign futures exchanges.

Purchasing and selling futures contracts on debt securities and on indices of debt securities may be used in order to hedge against anticipated changes in interest rates that might otherwise have an adverse effect upon the value of a Fund's securities. Such futures contracts may also be used for other appropriate risk management, income enhancement and investment purposes.

There are several risks associated with the use of futures contracts and options on futures contracts, including market price, interest rate, leverage, liquidity, counterparty, operational and legal risks. There can be no assurance that a liquid market will exist at the time when a Fund seeks to close out a futures contract. If no liquid market exists, a Fund would remain obligated to meet margin requirements until the position is closed. Futures may involve a small initial investment relative to the risk assumed, which could result in losses greater than if they had not been used. There can be no guarantee that there will be a correlation between price movements in the hedging vehicle and in a Fund's securities being hedged, even if the hedging vehicle closely correlates with the Fund’s investments, such as with single stock futures contracts. If the price of a futures contract changes more than the price of the securities or currencies, a Fund will experience either a loss or a gain on the futures contracts that will not be completely offset by changes in the price of the securities or currencies that are the subject of the hedge. In addition, there are significant differences between the securities and futures markets that could result in an imperfect correlation between the markets, causing a given hedge not to achieve its objectives.

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Growth Stocks

Growth stocks typically trade at higher multiples of current earnings than other securities. Therefore, the values of growth stocks may be more sensitive to changes in current or expected earnings than the values of other securities.

The principal risk of investing in growth stocks is that investors expect growth companies to increase their earnings at a certain rate that is generally higher than the rate expected for non-growth companies. If these expectations are not met, the market price of the stock may decline significantly, even if earnings showed an absolute increase. Growth stocks also typically lack the dividend yield that can cushion stock prices in market downturns.

Increase in Expenses Risk

The actual costs of investing in a Fund may be higher than the expenses shown in “Total Annual Fund Operating Expenses” for a variety of reasons. For example, expense ratios may be higher than those shown if average net assets decrease, as a result of redemptions or otherwise, or if a fee limitation is changed or terminated. Net assets are more likely to decrease and fund expense ratios are more likely to increase when markets are volatile.

Inflation Risk

A Fund's investments may be subject to inflation risk, which is the risk that the real value (i.e., nominal price of the asset adjusted for inflation) of assets or income from investments will be less in the future because inflation decreases the purchasing power and value of money (i.e., as inflation increases, the real value of a Fund's assets can decline as can the value of the Fund's distributions). Inflation rates may change frequently and significantly as a result of various factors, including unexpected shifts in the domestic or global economy and changes in monetary or economic policies (or expectations that these policies may change). The market price of debt securities generally falls as inflation increases because the purchasing power of the future income and repaid principal is expected to be worth less when received by a Fund. This risk of inflation is greater for debt instruments with longer maturities and especially those that pay a fixed rather than variable interest rate. In addition, this risk may be significantly elevated compared to normal conditions because of monetary policy measures and the current interest rate environment and level of government intervention and spending.

Infrastructure Industry Risk

The MainStay CBRE Global Infrastructure Fund is particularly exposed to adverse economic, regulatory, political, legal, and other changes affecting the issuers of infrastructure-related securities. Infrastructure-related companies are subject to a variety of factors that may adversely affect their business or operations, including high interest costs in connection with capital construction programs, costs associated with environmental and other regulations, the effects of economic slowdown and surplus capacity, increased competition from other providers of services, uncertainties concerning the availability of fuel at reasonable prices, the effects of energy conservation policies and other factors. Additionally, infrastructure-related companies may be subject to regulation by various governmental authorities and may also be affected by governmental regulation of rates charged to customers, service interruption and/or legal challenges due to environmental, operational or other mishaps and the imposition of special tariffs and changes in tax laws, regulatory policies and accounting standards. There is also the risk that corruption may negatively affect publicly-funded infrastructure projects, resulting in delays and cost overruns.

Specific infrastructure assets in which a Fund invests may be subject to the following additional risks:

· Communication infrastructure companies/issuers are subject to risks involving changes in government regulation, competition, dependency on patent protection, equipment incompatibility, changing consumer preferences, technological obsolescence and large capital expenditures and debt burdens.

· Energy infrastructure companies/issuers are subject to adverse changes in fuel prices, the effects of energy conservation policies and other risks, such as increased regulation, negative effects of economic slowdowns, reduced demand, cleanup and litigation costs as a result of environmental damage, changing and international politics and regulatory policies of various governments. Natural disasters or terrorist attacks damaging sources of energy supplies will also negatively impact energy infrastructure companies/issuers.

· Social infrastructure companies/issuers are subject to government regulation and the costs of compliance with such regulations and delays or failures in receiving required regulatory approvals. The enactment of new or additional regulatory requirements may negatively affect the business of a social infrastructure company.

· Transportation infrastructure companies/issuers can be significantly affected by economic changes, fuel prices, labor relations, insurance costs, government regulations, natural disasters or terrorist attacks.

· Utilities company revenues and costs are subject to regulation by states and other regulators. Regulatory authorities also may restrict a company’s access to new markets. Utilities companies may incur unexpected increases in fuel and other operating costs. Utilities companies are also subject to considerable costs associated with environmental compliance, nuclear waste clean-up and safety regulation.

Initial Public Offerings (“IPOs”)

IPO share prices are frequently volatile due to factors such as the absence of a prior public market for the shares, unseasoned trading in the shares, the small number of shares available for trading and limited information about the issuer’s business model, quality of

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management, earnings growth potential and other criteria used to evaluate its investment prospects. Investments in IPO shares, which are subject to market risk and liquidity risk, involve greater risks than investments in shares of companies that have traded publicly on an exchange for extended periods of time. Investments in IPO shares may have a magnified impact on the performance of a Fund with a small asset base. The impact of the investments in IPO shares on a Fund's performance will likely decrease as the Fund's asset size increases, which could reduce the Fund's returns. IPOs may not be consistently available for investing, particularly as the Fund's asset base grows. A Fund may hold IPO shares for a very short period of time, which may increase portfolio turnover and expenses, such as commissions and transaction costs. In addition, IPO shares can experience an immediate drop in value if the demand for the securities does not continue to support the offering price.

Investments in Other Investment Companies

A Fund may invest in other investment companies, including mutual funds, closed-end funds, and ETFs.

A Fund may purchase the securities of another investment company to temporarily gain exposure to a portion of the market while awaiting purchase of securities or as an efficient means of gaining exposure to a particular asset class. A Fund might also purchase shares of another investment company to gain exposure to the securities in the investment company’s portfolio at times when the Fund may not be able to buy those securities directly. Any investment in another investment company would be consistent with a Fund's objective and investment program. A Fund generally will directly bear its proportionate share of the management fees and other expenses that are charged by other investment companies, which also may be advised by the Manager or its affiliates, in addition to the management fees and other expenses paid by the Fund.

The risks of owning another investment company are generally similar to the risks of investment directly in the securities in which that investment company invests. However, an investment company may not achieve its investment objective or execute its investment strategy effectively, which may adversely affect performance. In addition, because listed closed-end funds and ETFs trade on a secondary market, their shares may trade at a premium or discount to the actual listed NAV of their portfolio securities and their shares may have greater volatility because of the potential lack of liquidity.

Large Investments or Redemptions by Shareholders Risk

From time to time, a Fund may receive large purchase or redemption orders from affiliated or unaffiliated mutual funds or other investors. Such large transactions could have adverse effects on performance if the Fund is required to sell securities, invest cash or hold significant cash at times when it otherwise would not do so. This activity could also accelerate the realization of capital gains and increase transaction costs. Certain shareholders, including clients or affiliates of the Manager and/or other funds managed by the Manager or its affiliates, may from time to time own or control a significant percentage of a Fund’s shares. Redemptions by these shareholders of their shares may further increase the liquidity risk and may otherwise adversely impact the Fund. These shareholders may include, for example, institutional investors, funds of funds, discretionary advisory clients and other shareholders whose buy-sell decisions are controlled by a single decision-maker. For more information, please see “Liquidity and Valuation Risk.”

Lending of Portfolio Securities

A Fund may lend its portfolio securities. Portfolio securities may be loaned to brokers, dealers and financial institutions to realize additional income under guidelines adopted by the Funds' Board. In determining whether to lend securities, the Manager or the Subadvisor or its/their agent will consider relevant facts and circumstances, including the creditworthiness of the borrower. Securities lending involves the risk that a Fund may lose money in the event that the borrower fails to return the securities in a timely manner or at all. A Fund also could lose money in the event of a decline in the value of the collateral provided for loaned securities or in the event that the borrower fails to provide additional collateral as needed to ensure the loan is fully collateralized. A Fund may also not experience the returns expected with the investment of cash collateral. Furthermore, as with other extensions of credit, a Fund could lose its rights in the collateral should the borrower fail financially. Another risk of securities lending is the risk that the loaned portfolio securities may not be available to a Fund on a timely basis and the Fund may therefore lose the opportunity to sell the securities at a desirable price. Any decline in the value of a security that occurs while the security is out on loan would continue to be borne by the Fund.

Liquidity and Valuation Risk

Liquidity risk is the risk that a Fund could not meet redemption requests within the allowable time period without significant dilution of remaining investors’ interests in the Fund. Liquidity risk exists when particular investments are difficult to sell, possibly preventing a Fund from selling the investments at an advantageous time or price. Liquidity risk may also exist because of unusual market conditions, government intervention, political, social, health, economic or market developments, unusually high volume of redemptions, or other reasons. To meet redemption requests, a Fund may be forced to sell securities at an unfavorable time and/or under unfavorable conditions. The liquidity of any Fund investment may change significantly over time as a result of market, economic, trading, issuer-specific and other factors.

Valuation risk refers to the potential that the sales price a Fund could receive for any particular investment may differ from the Fund’s valuation of the investment. Valuation of a Fund’s investments may be difficult, particularly for securities that trade in thin or volatile markets or that are valued using a fair value methodology that produces an estimate of the fair value of the security/instrument, which are based on good faith, subjective judgments, and available information. Such valuations may prove to be inaccurate. Where no clear or

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reliable indication of the value of a particular investment is available, the investment will be valued at its fair value according to valuation procedures approved by the Board. These cases include, among others, situations where the secondary markets on which a security has previously been traded are no longer viable for lack of liquidity. The value of illiquid investments may reflect a discount, which may be significant, from the market price of comparable securities for which a liquid market exists, and thus negatively affect a Fund's NAV. In addition, the value of illiquid investments that subsequently become liquid may increase, positively affecting the Fund's NAV. The Manager, as valuation designee, may rely on various sources of information to value investments and calculate NAVs. The Manager may obtain pricing information from third parties that are believed to be reliable. In certain cases, this information may be unavailable or this information may be inaccurate because of errors by the third parties, technological issues, an absence of current market data, or otherwise. These cases increase the risks associated with fair valuation.

Performance attributable to variations in liquidity are not necessarily an indication of future performance. For more information on fair valuation, please see "Fair Valuation and Portfolio Holdings Disclosure."

Loan Participation Interests

Loan participation interests, also referred to as Participations, are fractional interests in an underlying corporate loan and may be purchased from an agent bank, co-lenders or other holders of Participations. There are three types of Participations which a Fund may purchase. A Participation in a novation of a corporate loan involves a Fund assuming all of the rights of the lender in a corporate loan, including the right to receive payments of principal and interest and other amounts directly from the borrower and to enforce its rights as a lender directly against the borrower. Second, a Fund may purchase a Participation in an assignment of all or a portion of a lender's interest in a corporate loan, in which case the Fund may be required generally to rely on the assigning lender to demand payment and to enforce its rights against the borrower, but would otherwise be entitled to all of such lender's rights in the underlying corporate loan. Third, a Fund may also purchase a Participation in a portion of the rights of a lender in a corporate loan, in which case, a Fund will be entitled to receive payments of principal, interest and fees, if any, but generally will not be entitled to enforce its rights against the agent bank or borrower. The Fund must rely on the lending institution for that purpose.

The principal credit risk associated with acquiring Participations from a co-lender or another Participant is the credit risk associated with the underlying corporate borrower. A Fund may incur additional credit risk, however, when it is in the position of Participant rather than co-lender because the Fund must then assume the risk of insolvency of the co-lender from which the Participation was purchased and that of any person interposed between the Fund and the co-lender.

A Fund may not always have direct recourse against a borrower if the borrower fails to pay scheduled principal and/or interest and may be subject to greater delays, expenses and risks than if the Fund had purchased a direct obligation of the borrower. Substantial increases in interest rates may cause an increase in loan obligation defaults. Participations are subject to risks generally associated with debt securities; however, Participations may not be considered “securities,” and purchasers, such as a Fund, therefore may not be entitled to rely on the anti-fraud protections of the federal securities laws. A Fund may be in possession of material non-public information about a borrower or issuer as a result of its ownership of a Participation or security of such borrower or issuer. Because of prohibitions on trading in securities of issuers while in possession of such information, a Fund may be unable to enter into a transaction in a loan or security of such a borrower or issuer when it would otherwise be advantageous to do so.

Market Capitalization Risk

To the extent a Fund invests in securities issued by small-, mid-, or large-cap companies, it will be subject to the risks associated with securities issued by companies of the applicable market capitalization. Securities issued by companies of different market capitalizations tend to go in and out of favor based on market and economic conditions. During a period when securities of a particular market capitalization underperform other types of investments, a Fund's performance could be adversely impacted.

Securities of small-cap and mid-cap companies may be subject to greater price volatility, significantly lower trading volumes, cyclical, static or moderate growth prospects and greater spreads between their bid and ask prices than securities of larger companies. In addition, securities of small-cap and mid-cap companies may trade in an over-the-counter market or on a regional exchange, or may otherwise have limited liquidity. Smaller capitalization companies frequently rely on narrower product lines, niche markets, limited financial resources, a few key employees and inexperienced management. Smaller capitalization companies have more speculative prospects for future growth, sustained earnings and market share than larger companies and may be more vulnerable to adverse business or market developments. Accordingly, it may be difficult for a Fund to sell small-cap securities at a desired time or price. Generally, the smaller the company, the greater these risks become. Although securities issued by larger companies tend to have less overall volatility than securities issued by smaller companies, securities issued by larger companies may have less growth potential and may not be able to attain the high growth rates of successful smaller companies, especially during strong economic periods. In addition, larger companies may be less capable of responding quickly to competitive challenges and industry changes, including those resulting from improvements in technology, and may suffer sharper price declines as a result of earnings disappointments.

Market Risk

The value of a Fund's investments may fluctuate and/or decline because of changes in the markets in which the Fund invests, which could cause the Fund to underperform other funds with similar investment objectives and strategies. Security markets are volatile and

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may decline significantly in response to adverse issuer, regulatory, political, or economic developments. Different sectors of the market and different security types may react differently to such developments. Changes in these markets may be rapid and unpredictable. Fluctuations in the markets generally or in a specific industry or sector may impact the securities in which a Fund invests. From time to time, markets may experience periods of stress for potentially prolonged periods that may result in: (i) increased market volatility; (ii) reduced market liquidity; and (iii) increased redemptions. Such conditions may add significantly to the risk of volatility in the NAV of a Fund’s shares. Market changes may impact equity and fixed income securities in different and, at times, conflicting manners. A Fund potentially will be prevented from executing investment decisions at an advantageous time or price as a result of any domestic or global market disruptions, particularly disruptions causing heightened market volatility and reduced market liquidity, as well as increased or changing regulations. Thus, investments that the Manager or Subadvisor believes represent an attractive opportunity or in which a Fund seeks to obtain exposure may be unavailable entirely or in the specific quantities sought by the Manager or the Subadvisor and the Fund may need to obtain the exposure through less advantageous or indirect investments or forgo the investment at the time.

Political and diplomatic events within the United States and abroad, such as the U.S. budget and trade tensions, has in the past resulted, and may in the future result, in developments that present additional risks to a Fund's investments and operations. Geopolitical and other events, such as war, acts of terrorism, natural disasters, the spread of infectious illnesses, epidemics and pandemics, environmental and other public health issues, supply chain disruptions, inflation, recessions or other events, and governments’ reactions to such events, may lead to increased market volatility and instability in world economies and markets generally and may have adverse effects on the performance of a Fund and its investments. It is difficult to accurately predict or foresee when events or conditions affecting the U.S. or global financial markets, economies, and issuers may occur, the effects of such events or conditions, potential escalations or expansions of these events, possible retaliations in response to sanctions or similar actions and the duration or ultimate impact of those events. There is an increased likelihood that these types of events or conditions can, sometimes rapidly and unpredictably, result in a variety of adverse developments and circumstances, such as reduced liquidity, supply chain disruptions and market volatility, as well as increased general uncertainty and broad ramifications for markets, economies, issuers, businesses in many sectors and societies globally. Stocks of large capitalization issuers that are included as components of indices replicated by passively-managed funds may be particularly susceptible to declines in value, including declines in value that are not believed to be representative of the issuer’s fundamentals, due to market and investor reactions to such events. Additional and/or prolonged geopolitical or other events may affect investor and consumer confidence and may adversely impact financial markets and the broader economy, perhaps suddenly and to a significant degree. Any such market, economic and other disruptions could also prevent a Fund from executing its investment strategies and processes in a timely manner.

Master Limited Partnerships ("MLPs")

The MainStay CBRE Global Infrastructure Fund invests in MLPs that are qualified publicly traded partnerships under the Internal Revenue Code of 1986, as amended (the "Internal Revenue Code"). MLPs are limited partnerships in which ownership interests are publicly traded and are operated under the supervision of one or more general partners. Investments in MLPs carry many of the risks inherent in investing in a partnership. State law governing partnerships is often less restrictive than state law governing corporations. Accordingly, there may be fewer protections afforded to investors in an MLP. Limited partners may also have more limited control and limited rights to vote on matters affecting the MLP.

The anticipated benefits to be derived from a Fund's MLP investments will principally depend on the MLPs being treated as partnerships for U.S. federal income tax purposes. Partnerships generally are not subject to U.S. federal income tax at the partnership level. Rather, each partner is allocated and is generally subject to U.S. federal income tax on its share of the partnership’s income, gains, losses, deductions and expenses. A change in current tax law or in the underlying business activities of a given MLP could result in the MLP being treated as a corporation for U.S. federal income tax purposes, which would result in such MLP being subject to entity-level U.S. federal income tax (as well as state and local taxes) on its taxable income. The classification of an MLP as a corporation for U.S. federal income tax purposes would have the effect of reducing the amount of cash available for distribution by the MLP. Thus, if any of the MLPs owned by a Fund was treated as a corporation for U.S. federal income tax purposes, it could result in a reduction of the value of an investment in the Fund and lower income earned by the Fund. To the extent a distribution received by a Fund from an MLP equity security is treated as a return of capital, the Fund’s adjusted tax basis in the MLP equity security would be reduced by the amount of such distribution, which ultimately could result in an increase in an amount of income or gain (or decrease in the amount of loss) recognized by the Fund for tax purposes upon the sale or other disposition of such MLP equity security. Furthermore, any return of capital distributions received from an MLP equity security may require a Fund to restate the character of distributions made by the Fund as well as amend any previously issued shareholder tax reporting information.

MLP entities are typically focused in the energy, natural resources and real estate sectors of the economy. A downturn in these sectors of the economy could have an adverse impact on a Fund invested in MLPs. At times, the performance of securities of companies in these sectors of the economy may lag the performance of other sectors or the broader market as a whole.

Non-Diversification Risk

The MainStay CBRE Real Estate Fund is a non-diversified, open-end management investment company registered under the 1940 Act. A non-diversified fund may invest a greater portion of its assets in a more limited number of issuers than a diversified fund. A non-

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diversified Fund may select its investments from a relatively small pool of issuers together with securities issued by any newly public issuers consistent with its stated investment objective and policies. An investment in a non-diversified Fund may present greater risk to an investor than an investment in a diversified portfolio because changes in the financial condition or market assessment of a single issuer or small number of issuers may cause greater fluctuations in the value of the Fund’s shares.

Operational and Cyber Security Risk

Operational risk arises from a number of factors, including but not limited to, human error, processing and communication errors, errors of service providers, counterparties or other third-parties, failed or inadequate processes and technology or system failures. Additionally, a Fund and its service providers are susceptible to risks resulting from breaches in cyber security, including the theft, corruption, destruction or denial of access to data maintained online or digitally, denial of service on websites and other disruptions. Successful cyber security breaches may adversely impact a Fund and its shareholders by, among other things, interfering with the processing of shareholder transactions, impacting its ability to calculate its NAV, causing the release of confidential shareholder or Fund information, impeding trading, causing reputational damage and subjecting a Fund to fines, penalties or financial losses. A Fund seeks to reduce these operational and cyber security risks through controls and procedures. However, these measures do not address every possible risk and may be inadequate for those risks that they are intended to address.

Options

An option is a contract that gives the purchaser (holder) of the option, in return for a premium, the right, but not the obligation, to buy from (call) or sell to (put) the seller (writer) of the option the security, currency, index or futures contract underlying the option at a specified exercise price at a certain time or times during the term of the option, depending on the terms of the option. Entering into options contracts involves leverage risk, liquidity risk, counterparty risk, market risk, operational risk and legal risk. If the Manager or Subadvisor judges market conditions incorrectly or employs a strategy that does not correlate well with a Fund's investments, these techniques could result in a loss, regardless of whether the intent was to reduce risk or increase return. An investment in options may be subject to greater fluctuation than an investment in the underlying index or instrument itself. To the extent that a Fund writes or sells put options, the Fund could experience substantial losses in instances where the option's underlying index or instrument decreases below the exercise price of the written option. To the extent that a Fund writes or sells call options, the Fund could experience substantial losses in instances where the option's underlying index or instrument increases above the exercise price of the written option. Writing (selling) hedged options limits the opportunity to profit from changes in the market value of underlying indexes or instruments in exchange for up-front cash (the premium) at the time of selling the option.

Portfolio Management Risk

The investment strategies, practices and risk analysis used may not produce the desired results. In addition, a Fund may not achieve its investment objective, including during periods in which it takes temporary positions in response to unusual or adverse market, economic or political conditions, or other unusual or abnormal circumstances. The Subadvisor may be incorrect in its assessment of a particular security or market trend, which could result in losses. The Subadvisor's judgment about whether securities will increase or decrease in value may prove to be incorrect, and the value of these securities could change unexpectedly.

A quantitative model or algorithm ("quantitative tools") used by the Subadvisor, and the investments selected based on the quantitative tool, may not perform as expected. A quantitative tool may contain certain assumptions in construction and implementation that may adversely affect the Fund’s performance. There may also be technical issues with the construction and implementation of the quantitative tool (for example, software or other technology malfunctions, or programming inaccuracies). In addition, the Fund’s performance will reflect, in part, the Subadvisor’s ability to make active qualitative decisions and timely adjust the quantitative tool, including the tool’s underlying metrics and data.

To the extent that the Subadvisor determines not to pursue an investment opportunity for nonfinancial reasons, such as its ESG criteria, the Fund may forgo some market opportunities available to other funds.The application of ESG criteria may result in the Fund investing in securities or industry sectors that underperform the market as a whole, underperform other funds that do not take into account ESG criteria or underperform its benchmark. In addition, securities of companies that meet the ESG criteria may shift into and out of favor depending on market and economic conditions.

Preferred Stock Risk

Preferred stock generally has a preference as to dividends and upon liquidation over an issuer’s common stock but ranks junior to other income securities in an issuer’s capital structure. Preferred stock generally pays dividends in cash (or additional shares of preferred stock) at a defined rate but, unlike interest payments on other income securities, preferred stock dividends are payable only if declared by the issuer’s board of directors. Dividends on preferred stock may be cumulative, meaning that, in the event the issuer fails to make one or more dividend payments on the preferred stock, no dividends may be paid on the issuer’s common stock until all unpaid preferred stock dividends have been paid. Preferred stock also may provide that, in the event the issuer fails to make a specified number of dividend payments, the holders of the preferred stock will have the right to elect a specified number of directors to the issuer’s board. Preferred stock also may be subject to optional or mandatory redemption provisions. In addition, preferred stock may trade less frequently and in a more limited volume and may be subject to more abrupt or unpredictable price movements than certain other types of securities.

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In the event an issuer is liquidated or declares bankruptcy, the claims of owners of bonds take precedence over the claims of those who own preferred and common stock. If interest rates rise, the fixed dividend on preferred stocks may be less attractive, causing the price of preferred stocks to decline. Preferred stock may have mandatory sinking portfolio provisions, as well as provisions allowing the stock to be called or redeemed prior to its maturity, which can have a negative impact on the stock's price when interest rates decline.

Private Placement and Restricted Securities

Privately issued securities and other restricted securities are not publicly traded and generally are subject to strict restrictions on resale. Accordingly, there may be no market or a limited market for the resale of such securities. Therefore, a Fund may be unable to dispose of such securities when it desires to do so or at the most favorable price, which may result in a loss to a Fund. This potential lack of liquidity also may make it more difficult to accurately value these securities. There may be less information publicly available regarding such securities as compared to publicly issued securities. Privately issued securities that are determined to be “illiquid” would be subject to a Fund's policy of not investing more than 15% of its net assets in illiquid investments.

Restricted securities are securities that are sold only through negotiated private transactions and not to the general public, due to certain restrictions imposed by federal securities laws.

Real Estate Companies Risk

The MainStay CBRE Real Estate Fund invests in real estate companies, including REITs and real estate holdings companies, which will expose investors to the risks of owning real estate directly, as well as to the risks that relate specifically to the way in which such companies are organized and operated. These risks include, among others: possible declines in the value of real estate, risks related to general and local economic conditions, such as the possible decline in the income generated by the real estate; possible lack of availability of mortgage funds or other limitations on access to capital that may render the sale or refinancing of properties difficult or unattractive; overbuilding; risks associated with leverage, market illiquidity, extended vacancies of properties, increase in competition, property taxes, capital expenditures and operating expenses, changes in zoning laws or other governmental regulation; costs resulting from the clean-up of, and liability to third parties for damages resulting from environmental problems, tenants bankruptcies or other credit problems, casualty or condemnation losses, uninsured damages from floods, earthquakes or other natural disasters, limitations on and variations in rents, including decreases in market rates for rents; investment in developments that are not completed or that are subject to delays in completion; and changes in interest rates. To the extent that assets underlying a Fund’s investments are concentrated geographically, by property type on in certain other respects, the Fund may be subject to certain of the foregoing risks to a greater extent. Investments by a Fund in securities of issuers providing mortgage servicing will be subject to the risks associated with refinancing and their impact on servicing rights.

The real estate industry is particularly sensitive to economic downturns. The values of securities of companies in the real estate industry may go through cycles of relative under-performance and out-performance in comparison to equity securities markets in general. The U.S. real estate market may, in the future, experience and has, in the past, experienced a decline in value, with certain regions experiencing significant losses in property values. Many real estate companies, including REITs, utilize leverage (and some may be highly leveraged), which increases investment risk and the risk normally associated with debt financing, and could potentially increase a Fund’s volatility and losses. Exposure to such real estate may adversely affect Fund performance. In addition, real estate is generally a less liquid asset class and companies that hold real estate may not be able to liquidate or modify their holdings quickly in response to changes in economic or other market conditions. Companies in the real estate sector or in sectors that affect the performance of companies in the real estate sector (such as banking or financial institutions) may be subject to extensive government regulation, which may change unexpectedly and significantly impact the value of a Fund’s investments. Real estate income and values may also be greatly affected by demographic trends, such as population shifts or changing tastes, preferences (such as remote work arrangements) and values.

Real Estate Investment Trusts ("REITs")

The MainStay CBRE Real Estate Fund invests in REITs. REITs are pooled investment vehicles that invest primarily in either real estate or real estate-related loans. Investment in REITs carries with it many of the risks associated with direct ownership of real estate, including declines in property values extended vacancies, increases in property taxes, possible environmental liabilities and changes in interest rates. In addition to these risks, REITs are dependent upon management skills, may not be diversified, may experience substantial cost in the event of borrower or lessee defaults, and are subject to heavy cash flow dependency. REITs are also susceptible to the risks associated with the types of real estate investments they own and adverse economic or market events with respect to these securities and property types (e.g., apartment properties, retail shopping centers, office and industrial properties, hotels, healthcare facilities, manufactured housing and mixed-property types). For example, the value of these securities may decline when interest rates rise and will also be affected by the real estate market and by the management or development of the underlying properties, which may also be subject to mortgage loans and the underlying mortgage loans may be subject to the risks of default. A REIT could possibly fail to qualify for tax free pass-through of income under the Internal Revenue Code, or could fail to maintain its exemption from registration under the 1940 Act. The failure of a company to qualify as a REIT under federal tax law or maintain its exemption from registration under the 1940 Act may have adverse consequences.

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More About Investment Strategies and Risks

Regulatory Risk

Government regulation and/or intervention may change the way a Fund is regulated, affect the expenses incurred directly by the Fund, affect the value of its investments, and limit the Fund’s ability to achieve its investment objective. Government regulation may change frequently and may have significant adverse consequences. Moreover, government regulation may have unpredictable and unintended effects. In addition to exposing a Fund to potential new costs and expenses, additional regulation or changes to existing regulation may also require changes to a Fund's investment practices. Certain regulatory authorities may also prohibit or restrict the ability of a Fund to engage in certain derivative transactions or short-selling of certain securities. Although there continues to be uncertainty about the full impact of these and other regulatory changes, a Fund may be subject to a more complex regulatory framework, and incur additional costs to comply with new requirements as well as to monitor for compliance with any new requirements going forward.

At any time after the date of this Prospectus, legislation may be enacted that could negatively affect the assets of a Fund. Legislation or regulation may change the way in which a Fund is managed. Neither New York Life Investments nor the Subadvisor can predict the effects of any new governmental regulation that may be implemented, and there can be no assurance that any new governmental regulation will not adversely affect a Fund's ability to achieve its investment objective. A Fund's activities may be limited or restricted because of laws and regulations applicable to the Manager, the Subadvisor or the Fund.

Rights and Warrants Risk

The holder of a stock purchase right or a warrant has the right to purchase a given number of shares of a particular issuer at a specified price until expiration of the warrant. Such investments can provide a greater potential for profit or loss than an equivalent investment in the underlying security. Prices of rights and warrants do not necessarily move in tandem with the prices of the underlying securities, and warrants are speculative investments. Rights and warrants pay no dividends and confer no rights other than a purchase option. If a right or warrant is not exercised by the date of its expiration, a Fund will lose its entire investment in such right or warrant.

Risk Management Techniques

Various techniques can be used to increase or decrease exposure to changing security prices, interest rates, currency exchange rates, commodity prices or other factors that affect security values. These techniques may involve derivative transactions such as buying and selling futures contracts and options on futures contracts, entering into foreign currency transactions (such as foreign currency forward contracts and options on foreign currencies) and purchasing put or call options on securities and securities indices.

These practices can be used in an attempt to adjust the risk and return characteristics of a portfolio of investments. For example, to gain exposure to a particular market, a Fund may be able to purchase a futures contract with respect to that market. The use of such techniques in an attempt to reduce risk is known as "hedging." If the Manager or Subadvisor judges market conditions incorrectly or employs a strategy that does not correlate well with the Fund’s investments, these techniques could result in a loss, which in some cases may be unlimited, regardless of whether the intent was to reduce risk or increase return. These techniques may increase the volatility of a Fund and may involve a small investment of cash relative to the magnitude of the risk assumed. In addition, these techniques could result in a loss if the counterparty to the transaction does not perform as promised.

Short Selling

If a security sold short increases in price, a Fund may have to cover its short position at a higher price than the short sale price, resulting in a loss, which could be theoretically unlimited. By contrast, a loss on a long position arises from decreases in the value of the security and is limited by the fact that a security’s value cannot go below zero. A Fund may have substantial short positions and must borrow those securities to make delivery to the buyer. A Fund may not be able to borrow a security that it needs to deliver or it may not be able to close out a short position at an acceptable price and may have to sell related long positions before it had intended to do so. Thus, a Fund may not be able to successfully implement its short sale strategy due to limited availability of desired securities or for other reasons.

When borrowing a security for delivery to a buyer, a Fund also may be required to pay a premium and other transaction costs, which would increase the cost of the security sold short. A Fund must normally repay to the lender an amount equal to any dividends or interest that accrues while the loan is outstanding. The amount of any gain will be decreased, and the amount of any loss will be increased, by the amount of the premium, dividends, interest or expenses a Fund may be required to pay in connection with the short sale. Also, the lender of a security may terminate the loan at a time when a Fund is unable to borrow the same security for delivery. In that case, the Fund would need to purchase a replacement security at the then current market price or "buy in" by paying the lender an amount equal to the cost of purchasing the security.

Until a Fund replaces a borrowed security, it is required to maintain a segregated account of cash or liquid assets with a broker or custodian that is pledged for the benefit of the broker to cover a Fund's short position. Generally, securities held in a segregated account cannot be sold unless they are replaced with other liquid assets. A Fund's ability to access the pledged collateral may also be impaired in the event the broker fails to comply with the terms of the contract. In such instances, a Fund may not be able to substitute or sell the pledged collateral. This may limit a Fund's investment flexibility, as well as its ability to meet redemption requests or other current obligations.

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More About Investment Strategies and Risks

By investing the proceeds received from selling securities short, a Fund could be deemed to be employing a form of leverage, which creates special risks. The use of leverage may increase a Fund's exposure to long equity positions and make any change in a Fund's NAV greater than it would be without the use of leverage. This could result in increased volatility of returns. There is no guarantee that a Fund will leverage its portfolio, or if it does, that the Fund's leveraging strategy will be successful or that it will produce a higher return on an investment.

Tax Risk

Certain investments and investment strategies, including transactions in options and futures contracts, may be subject to special and complex federal income tax provisions, the effect of which may be, among other things: (i) to disallow, suspend, defer or otherwise limit the allowance of certain losses or deductions; (ii) to accelerate income to the Fund; (iii) to convert an ordinary loss or a deduction into a capital loss (the deductibility of which is more limited); and/or (iv) to produce income that will not qualify as good income under the gross income requirements that must be met for the Fund to qualify as a regulated investment company under Subchapter M of the Internal Revenue Code. Furthermore, to the extent that any futures contract or option on a futures contract held by the Fund is a “Section 1256 contract” under Section 1256 of the Internal Revenue Code, the contract will be marked to market annually, and any gain or loss will be treated as 60% long-term and 40% short-term, regardless of the holding period for such contract. Section 1256 contracts may include Fund transactions involving call options on a broad-based securities index, certain futures contracts and other financial contracts.

Temporary Defensive Investments

In times of unusual or adverse market, economic or political conditions or abnormal circumstances (such as large cash inflows or anticipated large redemptions), each Fund may, for temporary defensive purposes or for liquidity purposes (which may be for a prolonged period), invest outside the scope of its principal investment strategies. Under such conditions, a Fund may not invest in accordance with its investment objective or principal investment strategies and, as a result, there is no assurance that the Fund will achieve its investment objective. Under such conditions, each Fund may also invest without limit in cash, money market securities or other investments.

Value Stocks

A Fund may invest in companies that may not be expected to experience significant earnings growth, but whose securities their portfolio managers believe are selling at a price lower than their true value. Companies that issue such "value stocks" may have experienced adverse business developments or may be subject to special risks that have caused their securities to be out of favor. The principal risk of investing in value stocks is that they may never reach what the portfolio manager believes is their full value or that they may go down in value. If a portfolio manager's assessment of a company's prospects is wrong, or if the market does not recognize the value of the company, the price of that company's stock may decline or may not approach the value that the portfolio manager anticipates.

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Shareholder Guide

The information described in this Shareholder Guide is available free of charge by calling toll-free 800-624-6782 or by visiting our website at newyorklifeinvestments.com. The information contained in or otherwise accessible through the MainStay website does not form part of this Prospectus. For additional details, please contact your financial adviser or the MainStay Funds free of charge by calling toll-free 800-624-6782.

Please note that shares of the MainStay Funds are generally not available for purchase by foreign investors, except to certain qualified investors. The MainStay Funds reserve the right to: (i) pay dividends from net investment income and distributions from net capital gains in a check mailed to any investor who becomes a non-U.S. resident; (ii) redeem shares and close the account of an investor who becomes a non-U.S. resident; and (iii) redeem shares and close the account of an investor in the case of actual or suspected threatening conduct or actual or suspected fraudulent, suspicious or illegal activity by that investor or any other individual associated with that account.

SIMPLE IRA Plan accounts and certain other retirement plan accounts may not be eligible to invest in certain MainStay Funds.

The following terms are used in this Shareholder Guide:

· "MainStay Asset Allocation Funds" collectively refers to the MainStay Conservative Allocation Fund, MainStay Equity Allocation Fund, MainStay Growth Allocation Fund and MainStay Moderate Allocation Fund.

· "MainStay Epoch Funds" collectively refers to the MainStay Epoch Capital Growth Fund, MainStay Epoch U.S. Equity Yield Fund and MainStay Epoch Global Equity Yield Fund.

· “MainStay ETF Asset Allocation Funds” collectively refers to the MainStay Conservative ETF Allocation Fund, MainStay Defensive ETF Allocation Fund, MainStay Equity ETF Allocation Fund, MainStay ESG Multi-Asset Allocation Fund, MainStay Growth ETF Allocation Fund and MainStay Moderate ETF Allocation Fund.

· “MainStay Funds” collectively refers to each mutual fund managed by New York Life Investment Management LLC.

· "MainStay International/Global Equity Funds" collectively refers to the MainStay Candriam Emerging Markets Equity Fund, MainStay CBRE Global Infrastructure Fund, MainStay Epoch Capital Growth Fund, MainStay Epoch Global Equity Yield Fund, MainStay Epoch International Choice Fund, MainStay MacKay International Equity Fund, MainStay PineStone Global Equity Fund, MainStay PineStone International Equity Fund and MainStay WMC International Research Equity Fund.

· "MainStay Mixed Asset Funds" collectively refers to the MainStay Balanced Fund, MainStay Income Builder Fund and MainStay MacKay Convertible Fund.

· “MainStay Tax-Exempt Funds” collectively refers to the MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Term Municipal Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund.

· "MainStay Taxable Bond Funds" collectively refers to the MainStay Candriam Emerging Markets Debt Fund, MainStay Floating Rate Fund, MainStay MacKay High Yield Corporate Bond Fund, MainStay MacKay Short Duration High Yield Fund, MainStay MacKay Strategic Bond Fund, MainStay MacKay Total Return Bond Fund, MainStay MacKay U.S. Infrastructure Bond Fund, MainStay Money Market Fund and MainStay Short Term Bond Fund.

· "MainStay U.S. Equity Funds" collectively refers to the MainStay CBRE Real Estate Fund, MainStay Epoch U.S. Equity Yield Fund, MainStay Fiera SMID Growth Fund, MainStay S&P 500 Index Fund, MainStay PineStone U.S. Equity Fund, MainStay Winslow Large Cap Growth Fund, MainStay WMC Enduring Capital Fund, MainStay WMC Growth Fund, MainStay WMC Small Companies Fund and MainStay WMC Value Fund.

· The Board of Trustees of MainStay Funds Trust and the Board of Trustees of The MainStay Funds are collectively referred to as the "Board."

· The Investment Company Act of 1940, as amended, is referred to as the "1940 Act."

· New York Life Investment Management LLC is referred to as the "Manager" or "New York Life Investments."

· New York Life Insurance Company is referred to as "New York Life."

· NYLIM Service Company LLC is referred to as the "Transfer Agent" or "NYLIM Service Company."

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Shareholder Guide

· NYLIFE Distributors LLC, the MainStay Funds’ principal underwriter and distributor, is referred to as the "Distributor" or "NYLIFE Distributors."

· The New York Stock Exchange is referred to as the "Exchange."

· Net asset value is referred to as "NAV."

· The Securities and Exchange Commission is referred to as the "SEC."

· Automated Clearing House, the electronic process by which shares may be purchased or redeemed, is referred to as “ACH.”

The MainStay Funds offer Investor Class, Class A, A2, C, C2, I, P, R1, R2, R3, R6 and SIMPLE Class shares, as applicable. Each share class may not currently be offered by each MainStay Fund or through your financial intermediary and may be offered through a separate prospectus. Effective February 28, 2017, Class B shares were closed to all new purchases and additional investments by existing Class B shareholders. Each share class of a MainStay Fund represents an interest in the same portfolio of securities, has the same rights and is identical in all respects to the other classes (unless otherwise disclosed in this Shareholder Guide or as set forth in the MainStay Funds’ multiple class plan adopted pursuant to Rule 18f-3 under the 1940 Act), except that, to the extent applicable, each class also bears its own service and distribution expenses and may bear incremental transfer agency costs resulting from its investor base. In addition, each class has its own sales charge and expense structure, providing you with different choices for meeting the needs of your situation. Depending upon the number of shares of a MainStay Fund you choose to purchase, how you wish to purchase shares of a MainStay Fund and the MainStay Fund in which you wish to invest, the share classes available to you may vary.

The decision as to which class of shares is best suited to your needs depends on a number of factors that you should consider and discuss with your financial adviser. Important factors you may wish to consider include, among others:

· how much you plan to invest;

· how long you plan to hold your shares;

· the fees (e.g., sales charge) and total expenses associated with each class of shares; and

· whether you qualify for any reduction or waiver of the sales charge, if any, as discussed below in the section “Sales Charge Reductions and Waivers” and in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts.

The MainStay Funds, the Distributor and the Transfer Agent do not provide investment advice or recommendations or any form of tax or legal advice to existing or potential shareholders with respect to investment transactions involving the Funds. A shareholder transacting in (or holding) Fund shares through an intermediary should carefully review the fees and expenses charged by the intermediary relating to holding and transacting in Fund shares. These fees and expenses, including commissions, may vary by intermediary and customers of certain intermediaries are eligible only for the sales charge reductions or waivers set forth in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts. As a result, a shareholder purchasing or redeeming Fund shares through an intermediary may incur higher or lower costs than a shareholder purchasing or redeeming Fund shares through another intermediary or directly with the MainStay Funds. You may be required to pay a commission or other transaction charge to your financial intermediary when buying or selling shares of a share class that has no initial sales charge, contingent deferred sales charge, or asset-based fee for sales or distribution, such as Class I or Class R6 shares. These commissions or transaction charges are not reflected in the fee and expense table or expense examples for the share classes. The Funds make available other share classes that have different fees and expenses, which are disclosed and described in this Prospectus. Please contact your financial intermediary for more information on commissions or other transaction charges applicable to the purchase or redemption of shares of the Funds.

As with any business, operating a mutual fund involves costs. There are regular operating costs, such as investment advisory fees, distribution expenses, and custodial, transfer agency, legal and accounting fees, among others. These operating costs are typically paid from the assets of a MainStay Fund, and thus, all investors in the MainStay Fund (or share class, if applicable) indirectly share such costs. The expenses for each MainStay Fund are presented in the Funds’ respective Prospectuses in the tables entitled, "Fees and Expenses of the Fund," under the heading, "Annual Fund Operating Expenses." As the fee and expense tables show, certain costs are borne equally by each share class. In cases where services or expenses are class-specific, such as distribution and/or service (12b-1) fees, the fees payable for transfer agency services or certain other expenses, the costs are typically allocated differently among the share classes or among groups of share classes.

In addition to the direct expenses that a MainStay Fund bears, MainStay Fund shareholders indirectly bear the expenses of the other funds in which the MainStay Fund invests ("Underlying Funds"), where applicable. The tables entitled "Fees and Expenses of the Fund" reflect a MainStay Fund's estimated indirect expenses from investing in Underlying Funds based on the allocation of the MainStay Fund's assets among the Underlying Funds (if any) during the MainStay Fund's most recent fiscal year. These expenses may be higher or lower over time depending on the actual investments of the MainStay Fund's assets in the Underlying Funds and the actual expenses of the Underlying Funds.

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Shareholder Guide

In some cases, the Total Annual Fund Operating Expenses reflected in the tables entitled "Fees and Expenses of the Fund" may differ in part from the amounts shown in the Financial Highlights section of the applicable Prospectuses, which reflect only the operating expenses of a MainStay Fund for its prior fiscal year and do not include the MainStay Fund's share of the fees and expenses of any Underlying Fund in which the MainStay Fund invested during its prior fiscal year.

12b-1 and Shareholder Service Fees

Most significant among the class-specific costs are:

· Distribution and/or Service (12b-1) Fee—named after the SEC rule that permits their payment, 12b-1 fees are paid by a class of shares to compensate the Distributor for distribution and/or shareholder services such as marketing and selling MainStay Fund shares, compensating brokers and others who sell MainStay Fund shares, advertising, printing and mailing of prospectuses and responding to shareholder inquiries.

· Shareholder Service Fee—this fee covers certain services provided to retirement plans investing in Class R1, Class R2 and Class R3 shares that are not included under a 12b-1 plan for such class (if any), such as certain account establishment and maintenance, order processing, and communication services.

An important point to keep in mind about 12b-1 fees and shareholder service fees, which are paid out of Fund assets on an ongoing basis, is that they reduce the value of your shares, and therefore, will proportionately reduce the returns you receive on your investment and any dividends that are paid. See "Information on Fees" in this section for more information about these fees.

Sales Charges

In addition to regular operating costs, there are costs associated with an individual investor's transactions and account, such as the compensation paid to your financial adviser for helping you with your investment decisions. The MainStay Funds typically cover such costs by imposing sales charges and other fees directly on the investor either at the time of purchase or upon redemption for certain share classes. These charges and fees for each MainStay Fund are presented earlier in the tables entitled "Fees and Expenses of the Fund," under the heading, "Shareholder Fees." Such charges and fees include:

· Initial Sales Charge—also known as a "front-end sales load," refers to a charge that is deducted from your initial investment in Investor Class, Class A and Class A2 shares that is used to compensate the Distributor and/or your financial adviser for their efforts and assistance to you in connection with the purchase. The key point to keep in mind about a front-end sales load is that it reduces the initial amount invested in MainStay Fund shares.

· Contingent Deferred Sales Charge—also known as a "CDSC" or "back-end sales load," refers to a charge that is deducted from the proceeds when you redeem MainStay Fund shares (that is, sell shares back to the MainStay Fund). The amount of CDSC that you pay will depend on how long you hold your shares and decreases to zero if you hold your shares long enough. Although you pay no sales charge at the time of purchase, the Distributor typically pays your financial adviser a commission up-front. In part to compensate the Distributor for this expense, you will pay a higher ongoing 12b-1 fee over time for Class B, Class C or Class C2 shares. Subsequently, these fees may cost you more than paying an initial sales charge.

Distribution and/or service (12b-1) fees, shareholder service fees, initial sales charges and contingent deferred sales charges are each discussed in more detail later in this Shareholder Guide in the section “Information on Sales Charges.” Certain intermediaries impose different sales charges and make only specified waivers from sales charges available to their customers. These variations are described in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts. The following table provides a summary of the differences among share classes with respect to such fees and other important factors:

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Shareholder Guide

Summary of Important Differences Among Share Classes

1. Class A, Investor Class and Class C shares of the MainStay Money Market Fund are sold with no initial sales charge or CDSC and have no 12b-1 fees.

2. Class B shares are closed to all new purchases and additional investments by existing Class B shareholders.

3. No initial sales charge applies on investments of $1 million or more ($250,000 or more with respect to MainStay Asset Allocation Funds, MainStay Balanced Fund, MainStay ETF Asset Allocation Funds, MainStay Floating Rate Fund, MainStay Income Builder Fund, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund, MainStay MacKay Short Term Municipal Fund, MainStay MacKay Strategic Municipal Allocation Fund, MainStay MacKay Tax Free Bond Fund, MainStay MacKay U.S. Infrastructure Bond Fund and MainStay Short Term Bond Fund). However, for purchases of Class A and Investor Class shares of each Fund (except MainStay MacKay Short Term Municipal Fund and MainStay Short Term Bond Fund), a CDSC of 1.00% (0.50% for MainStay ETF Asset Allocation Funds) may be imposed on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. For purchases of Class A, Class A2 and Investor Class shares of MainStay MacKay Short Term Municipal Fund and Class A and Investor Class shares of MainStay Short Term Bond Fund, a CDSC of 0.50% may be imposed on redemptions made within 12 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

4. The CDSC period for MainStay Floating Rate Fund is a sliding scale during the first four years after purchase.

5. 18 months or less with respect to MainStay MacKay Short Duration High Yield Fund.

6. 0.25% for MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund.

7. 0.50% for MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund.

8. See the sections discussing Share Class Considerations and the section entitled "Buying, Selling, Converting and Exchanging Fund Shares—Conversions Between Share Classes" for more information on the voluntary and/or automatic conversions that apply to each share class.

9. Does not apply to purchases by certain retirement plans.

10. $250,000 for MainStay Asset Allocation Funds, MainStay Balanced Fund, MainStay ETF Asset Allocation Funds, MainStay Floating Rate Fund, MainStay Income Builder Fund, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund, MainStay MacKay Strategic Municipal Allocation Fund, MainStay MacKay Tax Free Bond Fund and MainStay MacKay U.S. Infrastructure Bond Fund.

The discussions in this Shareholder Guide are not intended to be investment advice or a recommendation because each investor's financial situation and considerations are different. Additionally, certain MainStay Funds have sales charge and expense structures that may alter your analysis as to which share class is most appropriate for your needs. This analysis can best be made by discussing your situation and the factors mentioned above with your financial adviser. Generally, however, Investor Class, Class A or Class A2 shares are more economical than Class C or Class C2 shares if you intend to invest larger amounts and hold your shares long-term (more than six years, for most MainStay Funds). Class C or Class C2 shares may be more economical than Investor Class, Class A or Class A2 shares if you intend to hold your shares for a shorter term. Class I, Class R6 and Class P shares are the most economical, regardless of amount invested or intended holding period. Class I shares are generally available only to certain institutional investors or through certain financial intermediary accounts or retirement plans. Class R6 shares are generally available only to certain retirement plans invested in a MainStay Fund through omnibus accounts (either at the plan level or omnibus accounts held on the books of the MainStay Fund). Class R1, Class R2 and Class R3 shares are available only to certain employer-sponsored retirement plans. Class P shares are generally only available to investors that have a relationship with PineStone Asset Management, Inc. and are investing directly with the Fund. SIMPLE Class shares are generally only available to SIMPLE IRA Plan accounts.

If the share class that is most economical for you, given your individual financial circumstances and goals, is not offered through your financial intermediary and you are otherwise eligible to invest in that share class, you can open an account and invest directly in the

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Shareholder Guide

MainStay Funds by submitting an application. Please see the section entitled “How to Open Your Account” in this Shareholder Guide and the SAI for details.

Investor Class Share Considerations

· Your Investor Class shares may convert automatically to Class A shares. Investor Class share balances are examined Fund-by-Fund on a quarterly basis. If, at that time, the value of your Investor Class shares in any one MainStay Fund equals or exceeds $15,000 ($10,000 in the case of IRA or 403(b)(7) accounts that are making required minimum distributions via the systematic withdrawal plan or systematic exchange program), whether by shareholder action or change in market value, or if you have otherwise become eligible to invest in Class A shares, your Investor Class shares of that MainStay Fund will be automatically converted into Class A shares. Eligible Investor Class shares may also convert upon request. Please note that, in most cases, you may not aggregate your holdings of Investor Class shares in multiple MainStay Funds/accounts or rely on a Right of Accumulation or Letter of Intent (each discussed below) to qualify for this conversion feature. Certain holders of Investor Class shares are not subject to this automatic conversion feature. For more information, please see the SAI.

· Share class conversions are based on the relevant NAVs of the two classes at the time of the conversion and no sales load or other charge is imposed upon conversion. The MainStay Funds expect all share class conversions described in this section to be made on a tax-free basis. The MainStay Funds reserve the right to modify or eliminate the share class conversion feature at any time. When a conversion occurs, reinvested dividends and capital gains convert with the shares that are converting.

· When you invest in Investor Class shares, you pay the public offering price, which is the share price, or NAV, plus the initial sales charge that may apply to your purchase. The amount of the initial sales charge varies based on the size of your investment (see "Information on Sales Charges"). We also describe below how you may reduce or eliminate the initial sales charge (see "Sales Charge Reductions and Waivers").

· Since some of your investment goes to pay an upfront sales charge when you purchase Investor Class shares, you will purchase fewer shares than you would with the same investment in certain other share classes. However, the net income attributable to Class C or Class C2 shares and the dividends payable on Class C or Class C2 shares will be reduced by the amount of the higher distribution and/or service (12b-1) fee and incremental expenses associated with each such class. Likewise, the NAV of the Class C or Class C2 shares generally will be reduced by such class-specific expenses (to the extent a MainStay Fund has undistributed net income) and investment performance of Class C or Class C2 shares will be lower than that of Investor Class shares. As a result, you are usually better off purchasing Investor Class shares rather than Class C or Class C2 shares and paying an up-front sales charge if you:

— plan to own the shares for an extended period of time, since the higher ongoing distribution and/or service (12b-1) fees on Class C or Class C2 shares may eventually exceed the cost of the up-front sales charge; or

— qualify for a reduced or waived sales charge.

Class A and Class A2 Share Considerations

· Generally, Class A and Class A2 shares have a minimum initial investment amount of $15,000 per MainStay Fund, however Class A shares of the MainStay ETF Asset Allocation Funds have a minimum initial investment amount of $2,500.

· When you invest in Class A or Class A2 shares, you pay the public offering price, which is the share price, or NAV, plus the initial sales charge that may apply to your purchase. The amount of the initial sales charge is based on the size of your investment (see "Information on Sales Charges"). We also describe below how you may reduce or eliminate the initial sales charge (see "Sales Charge Reductions and Waivers").

· Since some of your investment goes to pay an up-front sales charge when you purchase Class A or Class A2 shares, you will purchase fewer shares than you would with the same investment in certain other share classes. However, the net income attributable to Class C or Class C2 shares and the dividends payable on Class C or Class C2 shares will be reduced by the amount of the higher distribution and/or service (12b-1) fee and incremental expenses associated with such class. Likewise, the NAV of the Class C or Class C2 shares generally will be reduced by such class-specific expenses (to the extent a MainStay Fund has undistributed net income) and investment performance of Class C or Class C2 shares will be lower than that of Class A or Class A2 shares. As a result, you are usually better off purchasing Class A or Class A2 shares rather than Class C or Class C2 shares and paying an up-front sales charge if you:

— plan to own the shares for an extended period of time, since the higher ongoing distribution and/or service (12b-1) fees on Class C or Class C2 shares may eventually exceed the cost of the up-front sales charge; or

— qualify for a reduced or waived sales charge.

Class B Share Considerations

· Effective February 28, 2017, Class B shares of the MainStay Funds were closed to all new purchases as well as additional investments by existing Class B shareholders. Existing Class B shareholders may continue to reinvest dividends and capital gains distributions, as well as exchange their Class B shares for Class B shares of other MainStay Funds as permitted by the applicable exchange privileges. Class B shareholders will continue to be subject to any applicable contingent deferred sales charge at the

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Shareholder Guide

time of redemption. All other features of Class B shares, including but not limited to the fees and expenses applicable to Class B shares, will remain unchanged. Unless redeemed, Class B Shares shareholders will remain in Class B shares of their respective Fund until the Class B shares are converted to Class A or Investor Class shares pursuant to the applicable conversion schedule.

· When Class B shares were offered, no initial sales charge was incurred upon investment in Class B shares. However, you will pay higher ongoing distribution and/or service (12b-1) fees over the life of your investment. Over time these fees may cost you more than paying an initial sales charge on Investor Class or Class A shares. Consequently, it is important that you consider your investment goals and the length of time you intend to hold your shares when comparing your share class options.

· You should consult with your financial adviser to assess your Class B share investments in light of your particular circumstances.

· In most circumstances, you will pay a CDSC if you sell Class B shares within six years (four years with respect to MainStay Floating Rate Fund) of buying them (see "Information on Sales Charges"). Exchanging Class B shares into the MainStay Money Market Fund may impact your holding period. Please see “Exchanging Shares Among MainStay Funds” for more information. There are exceptions, which are described in the SAI.

· Selling Class B shares during the period in which the CDSC applies can significantly diminish the overall return on an investment.

· When you sell Class B shares of a MainStay Fund, to minimize your sales charges, the MainStay Funds first redeem the shares that have no sales charges (shares representing the amount of any appreciation on the original value of your shares, fully aged shares, and any shares received through the reinvestment of dividends and capital gains) and then the shares you have held longest.

· Class B shares convert to Class A shares, or Investor Class shares if you are not eligible to hold Class A shares, at the end of the calendar quarter, eight years (four years with respect to MainStay Floating Rate Fund) after the date they were purchased. This reduces distribution and/or service (12b-1) fees from 1.00% to 0.25% of average daily net assets (or from 0.50% to 0.25% with respect to MainStay MacKay Tax Free Bond Fund). Conversion features do not apply to Class B shares of the MainStay Money Market Fund that were exchanged from another MainStay Fund before their CDSC periods expired. Exchanging Class B shares into the MainStay Money Market Fund may impact your eligibility to convert at the end of the calendar quarter, eight years (four years with respect to MainStay Floating Rate Fund) after the date they were purchased. Please see “Exchanging Shares Among MainStay Funds” for more information.

· Share class conversions are based on the relevant NAVs of the two classes at the time of the conversion, and no sales load or other charge is imposed upon conversion. The MainStay Funds expect all share class conversions described in this section to be made on a tax-free basis. The MainStay Funds reserve the right to modify or eliminate this share class conversion feature at any time. When a conversion occurs, reinvested dividends and capital gains convert proportionately with the shares that are converting.

Class C and Class C2 Share Considerations

· You pay no initial sales charge on an investment in Class C or Class C2 shares. However, for certain Funds, you will pay higher ongoing distribution and/or service (12b-1) fees over the life of your investment than for each other share class.

· In most circumstances, you will pay a 1.00% CDSC if you redeem shares held for one year or less (18 months with respect to Class C shares of MainStay MacKay Short Duration High Yield Fund). Exchanging Class C or Class C2 shares may impact your holding period. Please see “Exchanging Shares Among MainStay Funds” for more information.

· When you sell Class C or Class C2 shares of a MainStay Fund, to minimize your sales charges, the MainStay Funds first redeem the shares that have no sales charges (shares representing the amount of any appreciation on the original value of your shares, fully aged shares, and any shares received through the reinvestment of dividends and capital gains) and then the shares you have held longest.

· Class C and, with respect to MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund, Class C2 shares convert to Class A shares, or Investor Class shares if you are not eligible to hold Class A shares, at the end of the calendar quarter, eight years after the date they were purchased. This reduces distribution and/or service (12b-1) fees from 1.00% to 0.25% of average daily net assets for Class C shares (or from 0.50% to 0.25% for Class C shares and from 0.65% to 0.25% for Class C2 shares with respect to MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund). Conversion features do not apply to Class C shares of the MainStay Money Market Fund that were exchanged from another MainStay Fund before their CDSC periods expired. Exchanging Class C or Class C2 shares into the MainStay Money Market Fund and/or holding Class C or Class C2 shares through a financial intermediary in an omnibus account may impact your eligibility to convert at the end of the calendar quarter, eight years after the date they were purchased. Please see “Conversions Between Share Classes” for more information.

· Share class conversions are based on the relevant NAVs of the two classes at the time of the conversion, and no sales load or other charge is imposed upon conversion. The MainStay Funds expect all share class conversions described in this section to be

35

Shareholder Guide

made on a tax-free basis. The MainStay Funds reserve the right to modify or eliminate this share class conversion feature at any time.

· The MainStay Funds will generally not accept a purchase order for Class C or Class C2 shares in the amount of $1,000,000 or more ($250,000 or more with respect to the MainStay Asset Allocation Funds, MainStay Balanced Fund, MainStay ETF Asset Allocation Funds, MainStay Floating Rate Fund, MainStay Income Builder Fund, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund, MainStay MacKay Strategic Municipal Allocation Fund, MainStay MacKay Tax Free Bond Fund and MainStay MacKay U.S. Infrastructure Bond Fund).

· Please note that Class C2 shares may not be available for initial or subsequent purchases through certain financial intermediary firms, investment platforms or in certain types of investment accounts. See the SAI for additional information.

Class I Share Considerations

· You pay no initial sales charge or CDSC on an investment in Class I shares.

· You do not pay any ongoing distribution and/or service (12b-1) fees.

· You may buy Class I shares if you are an:

— Institutional Investor

 Certain employer-sponsored, association or other group retirement plans or employee benefit trusts with a service arrangement through the Distributor or its affiliates;

 Certain financial institutions, endowments, foundations, government entities or corporations investing on their own behalf;

 Clients transacting through financial intermediaries that purchase Class I shares through: (i) fee-based accounts that charge such clients an ongoing fee for advisory, investment, consulting or similar services; (ii) a no-load network or platform that has entered into an agreement with the Distributor or its affiliates to offer Class I shares through a no-load network or platform; or (iii) brokerage accounts held at a broker that charges such clients transaction fees.

— Individual Investor who is initially investing at least $1 million in any single MainStay Fund: (i) directly with the MainStay Fund; or (ii) through certain private banks and trust companies that have an agreement with the Distributor or its affiliates.

— Existing Class I Shareholder; or

— Existing or retired MainStay Funds Trustee or Officer, current Portfolio Manager of a MainStay Fund or an employee of a Subadvisor.

· The MainStay asset allocation funds may invest in Class I shares, if Class R6 shares for a Fund are unavailable.

Class P Share Considerations

· You pay no initial sales charge or CDSC on an investment in Class P shares.

· You do not pay any ongoing distribution and/or service fees (12b-1) fees.

· Generally, Class P shares are only available to investors that have a relationship with PineStone Asset Management Inc. and are investing directly with the Fund.

Class R1, Class R2, Class R3, Class R6 and SIMPLE Class Share Considerations

· You pay no initial sales charge or CDSC on an investment in Class R1, Class R2, Class R3, Class R6 or SIMPLE Class shares.

· You pay ongoing shareholder service fees for Class R1, Class R2 and Class R3 shares. You also pay ongoing distribution and/or service (12b-1) fees for Class R2, and Class R3 shares.

· You do not pay ongoing shareholder service fees or ongoing distribution and/or service fees (12b-1) fees for Class R6 shares.

· You pay ongoing distribution and/or service fees (12b-1) fees but do not pay ongoing shareholder service fees for SIMPLE Class shares.

· Class R1, Class R2 and Class R3 shares are available in certain individual retirement accounts and in certain retirement plans that have a service arrangement with the Distributor, including:

— Section 401(a) and 457 plans;

— Certain Section 403(b)(7) plans;

— Section 401(k), profit sharing, money purchase pension, Keogh and defined benefit plans; and

— Non-qualified deferred compensation plans.

· Generally, Class R6 shares are only available to certain employer-sponsored retirement plans held with a Fund through omnibus accounts (either at the plan level or omnibus accounts held on the books of the Fund) that have a service arrangement with the Distributor or its affiliate, such as Section 401(k), profit sharing, money purchase pension and defined benefit plans. However, the Fund reserves the right in its sole discretion to waive this eligibility requirement.

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Shareholder Guide

· SIMPLE Class shares are generally only available to SIMPLE IRA Plan accounts.

· SIMPLE Class shares convert to Class A shares, or Investor Class shares if you are not eligible to hold Class A shares, at the end of the calendar quarter, ten years after the date they were purchased. Share class conversions are based on the relevant NAVs of the two classes at the time of the conversion, and no sales load or other charge is imposed. The MainStay Funds expect all share class conversions described in this section to be made on a tax-free basis. The MainStay Funds reserve the right to modify or eliminate this share class conversion feature at any time.

· The MainStay asset allocation funds may invest in Class R6 shares, if available.

The following minimums apply if you are investing in a MainStay Fund. A minimum initial investment amount may be waived for purchases by the Trustees and directors and employees of New York Life and its affiliates and subsidiaries. The MainStay Funds may also waive investment minimums for certain qualified purchases and accept additional investments of smaller amounts at their discretion. Please see the SAI for additional information.

Investor Class Shares

All MainStay Funds except MainStay Candriam Emerging Markets Equity Fund, MainStay Cushing MLP Premier Fund, MainStay Epoch Funds, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund and MainStay WMC Growth Fund:

· $1,000 minimum for initial and $50 minimum for subsequent purchases of any of these MainStay Funds, or

· if through AutoInvest, a monthly systematic investment plan: $500 minimum for initial and $50 minimum for subsequent monthly purchases (except MainStay Money Market Fund, which requires an initial investment amount of $1,000).

MainStay Candriam Emerging Markets Equity Fund, MainStay Cushing MLP Premier Fund, MainStay Epoch Funds, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund and MainStay WMC Growth Fund:

· $2,500 minimum for initial and $50 minimum for subsequent purchases of any of these MainStay Funds, or

· if through AutoInvest, a monthly systematic investment plan: $2,500 minimum for initial and $50 minimum for subsequent monthly purchases.

Class A Shares

All MainStay Funds except MainStay ETF Asset Allocation Funds and MainStay Money Market Fund:

· $15,000 minimum initial investment with no minimum for subsequent purchases of any of these MainStay Funds.

MainStay ETF Asset Allocation Funds:

· $2,500 minimum for initial and no minimum for subsequent purchases of any of these MainStay Funds, or

· if through AutoInvest, a monthly systematic investment plan: $500 minimum for initial and $50 minimum for subsequent monthly purchases.

MainStay Money Market Fund:

· There are no minimums for initial and subsequent purchases if all of your other accounts contain Class A shares only.

· Please note that if at any time you hold any class of shares other than Class A shares, your holdings in the MainStay Money Market Fund will immediately become subject to the applicable investment minimums, subsequent purchase minimums and subsequent conversion features for Class A shares.

Broker/dealers (and their affiliates) or certain service providers with customer accounts that trade primarily on an omnibus level or through the National Securities Clearing Corporation's Fund/SERV network (Levels 1-3 only); certain retirement plan accounts, including investment-only plan accounts; directors and employees of New York Life and its affiliates; investors who obtained their Class A shares through certain reorganizations (including holders of Class P shares of any of the predecessor funds to the MainStay Epoch Funds as of November 16, 2009); and subsidiaries and employees of the Subadvisors are not subject to the minimum investment requirement for Class A shares, however MainStay Funds reserve the right to impose other minimum initial investment amounts on these accounts. See the SAI for additional information.

Class A2 Shares

MainStay MacKay Short Term Municipal Fund:

· $15,000 minimum for initial and no minimum for subsequent purchases.

Class C Shares

All MainStay Funds except MainStay Candriam Emerging Markets Equity Fund, MainStay Cushing MLP Premier Fund, MainStay Epoch Funds, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund and MainStay WMC Growth Fund:

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Shareholder Guide

· $1,000 minimum for initial and $50 minimum for subsequent purchases of any of these MainStay Funds, or

· if through AutoInvest, a monthly systematic investment plan: $500 minimum for initial and $50 minimum for subsequent monthly purchases (except MainStay Money Market Fund, which requires an initial investment amount of $1,000).

MainStay Candriam Emerging Markets Equity Fund, MainStay Cushing MLP Premier Fund, MainStay Epoch Funds, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund and MainStay WMC Growth Fund:

· $2,500 minimum for initial and $50 minimum for subsequent purchases of any of these MainStay Funds, or

· if through AutoInvest, a monthly systematic investment plan: $2,500 minimum for initial and $50 minimum for subsequent monthly purchases.

Investors who obtained their Class C shares through certain reorganizations are not subject to the minimum investment requirements for Class C shares. See the SAI for additional information.

Class C2 Shares

MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund:

· $1,000 minimum for initial and $50 minimum for subsequent purchases, or

· if through AutoInvest, a monthly systematic investment plan: $500 minimum for initial and $50 minimum for subsequent monthly purchases.

MainStay MacKay California Tax Free Opportunities Fund and MainStay MacKay New York Tax Free Opportunities Fund:

· $2,500 minimum for initial and $50 minimum for subsequent purchases of any of these MainStay Funds, or

· if through AutoInvest, a monthly systematic investment plan: $2,500 minimum for initial and $50 minimum for subsequent monthly purchases.

Class I Shares

· Individual Investors—$1 million minimum for initial purchases of any single MainStay Fund and no minimum for subsequent purchases of any other MainStay Fund; and

· Institutional Investors, the MainStay Funds' existing and retired Trustees and Officers, current Portfolio Managers of the MainStay Funds and employees of Subadvisors—no minimums for initial and subsequent purchases of any MainStay Fund.

Please note that Class I shares may not be available for initial or subsequent purchases through certain financial intermediary firms, investment platforms or in certain types of investment accounts. See the SAI for additional information.

Investors who obtained their Class I shares through certain reorganizations are not subject to the minimum investment requirements for Class I shares. See the SAI for additional information.

Class P Shares

MainStay PineStone Global Equity Fund, MainStay PineStone International Equity Fund and MainStay PineStone U.S. Equity Fund:

· If you are eligible to invest in Class P shares, $5,000,000 minimum for initial and no minimum for subsequent purchases if you are eligible to invest in Class P shares.

Please note that Class P shares may not be available for initial or subsequent purchases through certain financial intermediary firms, investment platforms or in certain types of investment accounts. See the SAI for additional information.

Class R1, Class R2, Class R3 and Class R6 Shares

If you are eligible to invest in Class R1, Class R2, Class R3 or Class R6 shares of the MainStay Funds, there are no minimums for initial and subsequent purchases.

SIMPLE Class Shares

All MainStay Funds except MainStay Money Market Fund, MainStay Asset Allocation Funds and MainStay ETF Asset Allocation Funds:

· $1,000 minimum for initial and no minimum for subsequent purchases of any of these MainStay Funds.

MainStay Money Market Fund, MainStay Asset Allocation Funds and MainStay ETF Asset Allocation Funds:

· There are no minimums for initial and subsequent purchases of any of these MainStay Funds.

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Shareholder Guide

The MainStay Funds make available (free of charge) information regarding sales charges at newyorklifeinvestments.com/salescharges.

Investor Class, Class A and Class A2 Shares

The initial sales charge you pay when you buy Investor Class, Class A or Class A2 shares differs depending upon the MainStay Fund you choose and the amount you invest, as indicated in the following tables. The sales charge may be reduced or eliminated for larger purchases, as described below, or as described under "Sales Charge Reductions and Waivers" or for shares purchased or accounts held through particular financial intermediaries as set forth in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts. Any applicable sales charge will be deducted directly from your investment. All or a portion of the sales charge may be retained by the Distributor or paid to your financial intermediary firm as a concession. Investor Class shares and Class A shares of MainStay Money Market Fund are not subject to a sales charge.

MainStay Candriam Emerging Markets Equity Fund, MainStay CBRE Global Infrastructure Fund, MainStay CBRE Real Estate Fund, MainStay Cushing MLP Premier Fund, MainStay Epoch Capital Growth Fund, MainStay Epoch Global Equity Yield Fund, MainStay Epoch International Choice Fund, MainStay Epoch U.S. Equity Yield Fund, MainStay Fiera SMID Growth Fund, MainStay MacKay Convertible Fund, MainStay MacKay International Equity Fund, MainStay PineStone Global Equity Fund, MainStay PineStone International Equity Fund, MainStay PineStone U.S. Equity Fund, MainStay Winslow Large Cap Growth Fund, MainStay WMC Enduring Capital Fund, MainStay WMC Growth Fund, MainStay WMC International Research Equity Fund, MainStay WMC Small Companies Fund and MainStay WMC Value Fund

Class A Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $1 million or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Investor Class Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $1 million or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

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Shareholder Guide

MainStay S&P 500 Index Fund

Class A Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $1 million or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Investor Class Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $1 million or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

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Shareholder Guide

MainStay Candriam Emerging Markets Debt Fund, MainStay MacKay High Yield Corporate Bond Fund, MainStay MacKay Strategic Bond Fund and MainStay MacKay Total Return Bond Fund

Class A Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $1 million or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Investor Class Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $1 million or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

MainStay Balanced Fund, MainStay Conservative Allocation Fund, MainStay Conservative ETF Allocation Fund, MainStay Defensive ETF Allocation Fund, MainStay Equity Allocation Fund, MainStay Equity ETF Allocation Fund, MainStay ESG Multi-Asset Allocation Fund, MainStay Floating Rate Fund, MainStay Growth Allocation Fund, MainStay Growth ETF Allocation Fund, MainStay Income Builder Fund, MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay High Yield Municipal Bond Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Short Duration High Yield Fund, MainStay MacKay Strategic Municipal Allocation Fund, MainStay MacKay Tax Free Bond Fund, MainStay MacKay U.S. Infrastructure Bond Fund, MainStay Moderate Allocation Fund and MainStay Moderate ETF Allocation Fund

Class A Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $250,000 or more. A contingent deferred sales charge of 1.00% (0.50% for each MainStay ETF Asset Allocation Fund) may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

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Shareholder Guide

Investor Class Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $250,000 or more. A contingent deferred sales charge of 1.00% may be imposed, however, on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

MainStay Short Term Bond Fund and MainStay MacKay Short Term Municipal Fund

Class A Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $250,000 or more. A contingent deferred sales charge of 0.50% may be imposed, however, on redemptions made within 12 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Class A2 Shares (MainStay MacKay Short Term Municipal Fund only)

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $250,000 or more. A contingent deferred sales charge of 0.50% may be imposed, however, on redemptions made within 12 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Investor Class Shares

1. The sales charge you pay may differ slightly from the amounts listed here due to rounding calculations.

2. No sales charge applies on investments of $250,000 or more. A contingent deferred sales charge of 0.50% may be imposed, however, on redemptions made within 12 months of the date of purchase on shares that were purchased without an initial sales charge. The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Sales charges that are specific to customers of a specific intermediary are set forth in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts.

Class B Shares

Effective February 28, 2017, Class B shares were closed to all new purchases and additional investments by existing Class B shareholders. Class B shares were sold without an initial sales charge. However, if Class B shares are redeemed within six years (four years with respect to MainStay Floating Rate Fund) of their purchase, a CDSC will be deducted from the redemption proceeds, except under circumstances described below. Additionally, for certain Funds, Class B shares have higher ongoing distribution and/or service (12b-1) fees than for other share classes and, over time, these fees may cost you more than paying an initial sales charge. The Class B share CDSC and the higher ongoing distribution and/or service (12b-1) fees are paid to compensate the Distributor for its expenses in connection with the sale of Class B shares. Class B shares of MainStay Money Market Fund are not subject to a sales charge. The

42

Shareholder Guide

amount of the CDSC will depend on the number of years you have held the shares that you are redeeming, according to the following schedule:

All MainStay Funds which offer Class B Shares (except MainStay Floating Rate Fund)

MainStay Floating Rate Fund

Class C Shares

Class C shares are sold without an initial sales charge. However, if Class C shares are redeemed within one year of purchase (18 months with respect to MainStay MacKay Short Duration High Yield Fund), a CDSC of 1.00% will be deducted from the redemption proceeds, except under circumstances described below. Additionally, Class C shares have higher ongoing distribution and/or service (12b-1) fees than other share classes (except Class B and, with respect to MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund, Class C2 shares) and, over time, these fees may cost you more than paying an initial sales charge. The Class C share CDSC and the higher ongoing distribution and/or service (12b-1) fees are paid to compensate the Distributor for its expenses in connection with the sale of Class C shares. Class C shares of MainStay Money Market Fund are not subject to a sales charge.

Class C2 Shares

Class C2 shares are sold without an initial sales charge. However, if Class C2 shares are redeemed within one year of purchase, a CDSC of 1.00% will be deducted from the redemption proceeds, except under circumstances described below. Additionally, for certain Funds, Class C2 shares have higher ongoing distribution and/or service (12b-1) fees than other share classes and, over time, these fees may cost you more than paying an initial sales charge. The Class C2 share CDSC and the higher ongoing distribution and/or service (12b-1) fees are paid to compensate the Distributor for its expenses in connection with the sale of Class C2 shares.

Computing Contingent Deferred Sales Charge on Class B, Class C and Class C2 Shares

Subject to certain exceptions, a CDSC will be imposed on redemptions of Class B, Class C or Class C2 shares of a MainStay Fund, at the rates previously described, at the time of any redemption by a shareholder that reduces the current value of the shareholder's Class B, Class C or Class C2 share account to an amount that is lower than the amount of all payments by the shareholder for the purchase of Class B shares during the preceding six years (four years with respect to MainStay Floating Rate Fund) or Class C or Class C2 shares during the preceding year (18 months with respect to Class C shares of MainStay MacKay Short Duration High Yield Fund). The CDSC is calculated based on the lesser of the offering price or the market value of the shares being sold. The MainStay Funds first redeem the shares that have no sales charges (shares representing the amount of any appreciation on the original value of your shares, fully aged shares, and any shares received through the reinvestment of dividends and capital gains) and then the shares you have held longest.

For example, no CDSC will be imposed to the extent that the NAV of the Class B, Class C or Class C2 shares redeemed does not exceed:

· the current aggregate NAV of Class B, Class C or Class C2 shares of the MainStay Fund purchased more than six years (four years with respect to MainStay Floating Rate Fund) prior to the redemption for Class B shares or more than one year (18 months with respect to Class C shares of MainStay MacKay Short Duration High Yield Fund) prior to the redemption for Class C or Class C2 shares; plus

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Shareholder Guide

· the current aggregate NAV of Class B, Class C or Class C2 shares of the MainStay Fund purchased through reinvestment of dividends or capital gain distributions; plus

· increases in the NAV of the investor's Class B, Class C or Class C2 shares of the MainStay Fund above the total amount of payments for the purchase of Class B, Class C or Class C2 shares of the MainStay Fund made during the preceding six years (four years with respect to MainStay Floating Rate Fund) for Class B shares or one year (18 months with respect to Class C shares of MainStay MacKay Short Duration High Yield Fund) for Class C or Class C2 shares.

There are exceptions, which are described below.

Further information regarding sales charges is available in the SAI.

The MainStay Funds make available (free of charge) information regarding sales charge reductions and waivers on our website at newyorklifeinvestments.com/salescharges.

Reducing the Initial Sales Charge on Investor Class, Class A and Class A2 Shares

You may be eligible to buy Investor Class, Class A and Class A2 shares of the MainStay Funds at one of the reduced sales charge rates shown in the tables above through a Right of Accumulation or a Letter of Intent, as briefly described below. You may also be eligible for a waiver of the initial sales charge as set forth below or in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts. Each MainStay Fund reserves the right to modify or eliminate these programs at any time. However, please note the Right of Accumulation or Letter of Intent may only be used to reduce sales charges and may not be used to satisfy investment minimums or to avoid the automatic conversion feature of Investor Class shares.

· Right of Accumulation

A Right of Accumulation allows you to reduce the initial sales charge as shown in the tables above by combining the amount of your current purchase with the current market value of investments made by you, your spouse, and your children under age 21 in Investor Class, Class A, Class A2, Class B, Class C, Class C2 or SIMPLE Class shares of most MainStay Funds. You may not include investments of previously non-commissioned shares in the MainStay Money Market Fund, investments in Class I shares, or your interests in any MainStay Fund held through a 401(k) plan or other employee benefit plan. For example, if you currently own $45,000 worth of Class C shares of a MainStay Fund, your spouse owns $50,000 worth of Class B shares of another MainStay Fund, and you wish to invest $15,000 in a MainStay Fund, using your Right of Accumulation you can invest that $15,000 in Investor Class or Class A shares and pay the reduced sales charge rate normally applicable to a $110,000 investment. For more information, please see the SAI.

· Letter of Intent

Whereas the Right of Accumulation allows you to use prior investments to reach a reduced initial sales charge, a Letter of Intent allows you to qualify for a discount by combining your current purchase amount with purchases you, your spouse or children under age 21 intend to make in the near future. A Letter of Intent is a written statement of your intention to purchase Investor Class, Class A, Class A2, Class C, Class C2 or SIMPLE Class shares of one or more MainStay Funds (excluding investments of non-commissioned shares in the MainStay Money Market Fund) over a 24-month period. The total amount of your intended purchases will determine the reduced sales charge rate that will apply to Investor Class, Class A or Class A2 shares of the MainStay Funds purchased during that period. You can also apply a Right of Accumulation to these purchases.

Your Letter of Intent goal must be at least $100,000. Submitting a Letter of Intent does not obligate you to purchase the specified amount of shares. If you do not meet your intended purchase goal, the initial sales charge that you paid on your purchases will be recalculated to reflect the actual value of shares purchased. A certain portion of your shares will be held in escrow by the Transfer Agent for this purpose. For more information, please see the SAI.

· Your Responsibility

To receive the reduced sales charge, you must inform the Transfer Agent of your eligibility and holdings at the time of your purchase if you are buying shares directly from the MainStay Funds. If you are buying MainStay Fund shares through a financial intermediary firm, you must tell your financial adviser of your eligibility for a Right of Accumulation or a Letter of Intent at the time of your purchase.

To combine shares of eligible MainStay Funds held in accounts at other intermediaries under your Right of Accumulation or a Letter of Intent, you may be required to provide the Transfer Agent or your financial adviser a copy of each account statement showing your current holdings of each eligible MainStay Fund, including statements for accounts held by you, your spouse or your children under age 21, as described above. The Transfer Agent or intermediary through which you are buying shares will combine the value of all your eligible MainStay Fund holdings based on the current NAV per share to determine what Investor Class, Class A or Class A2 sales charge rate you may qualify for on your current purchase. If you do not inform the Transfer Agent or your financial adviser of all of your

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MainStay Fund holdings or planned MainStay Fund purchases that make you eligible for a sales charge reduction or do not provide requested documentation, you may not receive the discount to which you are otherwise entitled.

"Spouse," with respect to a Right of Accumulation and Letter of Intent, is defined as the person to whom you are legally married. We also consider your spouse to include one of the following: (i) an individual of the same gender with whom you have been joined in a civil union or legal contract similar to marriage; (ii) a domestic partner, who is an individual (including one of the same gender) to whom you are not related by blood and with whom you have shared a primary residence for at least six months in a relationship as a couple where you, your domestic partner or both of you provide for the personal or financial welfare of the other without a fee; or (iii) an individual with whom you have a common law marriage, which is a marriage in a state where such marriages are recognized between a man and a woman arising from the fact that the two live together and hold themselves out as being married.

Purchases at Net Asset Value

A Fund's Class A or Class A2 shares may be purchased at NAV, without payment of any sales charge, by its current and former Trustees; New York Life and its subsidiaries and their employees, officers, directors, or agents or former employees (and immediate family members); individuals and other types of accounts purchasing through "wrap fee" or other programs sponsored by a financial intermediary firm; employees (and immediate family members) of the Subadvisors; any employee or registered representative of a financial intermediary firm (and immediate family members) and any employee of SS&C GIDS, Inc. that is assigned to the Fund. Individuals and other types of accounts may purchase Class A2 shares at NAV, without payment of any sales charge, if exchanged for Class A shares of the same fund through a financial intermediary's share class conversion program. Class A shares, Class A2 shares or Investor Class shares may be purchased without an initial sales load by qualified tuition programs operating under Section 529 of the Internal Revenue Code.

There is no sales charge on shares purchased through the automatic reinvestment of dividends or capital gains.

Class A shares of the MainStay Funds also may be purchased at NAV, without payment of any sales charge, by shareholders:

(i) who owned Service Class shares of a series of Eclipse Trust (the predecessor trust for certain Funds) or certain series of MainStay Funds Trust, as of December 31, 2003, and who are invested directly with and have maintained their account with the Fund; and

(ii) who owned Class P shares of certain Epoch Funds as of the closing date of their reorganization and who are invested directly with and have maintained their account with the Funds.

Purchases Through Financial Intermediaries

The MainStay Funds have authorized financial intermediary firms (such as a broker/dealers, financial advisers or financial institutions), and other intermediaries that the firms may designate, to accept orders. When an authorized firm or its designee has received your order, together with the purchase price of the shares, it is considered received by the MainStay Funds and will be priced at the next computed NAV. Financial intermediary firms may charge transaction fees or other fees and may modify other features such as minimum investment amounts, share class eligibility and exchange privileges.

Please read your financial intermediary firm’s program materials for any special provisions or additional service features that may apply to investing in the MainStay Funds through the firm.

The availability of initial sales charge waivers (and discounts) may depend on the particular financial intermediary or type of account through which you purchase MainStay Fund shares. The MainStay Funds’ initial sales charge waivers disclosed in this Prospectus and the SAI are available through financial intermediaries. The initial sales charge waivers available only to customers of certain other financial intermediaries are set forth in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts to this Prospectus. For these customers, the sales charge waivers offered by the MainStay Funds may not be available for transactions through the intermediary. Please contact your financial intermediary regarding the availability of applicable sales charge waivers and information regarding the intermediary’s related policies and procedures.

Contingent Deferred Sales Charge on Certain Investor Class, Class A and Class A2 Share Redemptions

For purchases of Class A and Investor Class shares of each MainStay Fund (except MainStay MacKay Short Term Municipal Fund and MainStay Short Term Bond Fund), a CDSC of 1.00% (0.50% for the MainStay ETF Asset Allocation Funds) may be imposed on redemptions made within 18 months of the date of purchase on shares that were purchased without an initial sales charge. For purchases of Class A, Class A2 and Investor Class shares of MainStay MacKay Short Term Municipal Fund and Class A and Investor Class shares of MainStay Short Term Bond Fund, a CDSC of 0.50% may be imposed on redemptions made within 12 months of the date of purchase on shares that were purchased without an initial sales charge.

The Distributor may pay a commission to financial intermediary firms on these purchases from its own resources. See "Sales Charge Reductions and Waivers - Waivers of Contingent Deferred Sales Charges" below.

Waivers of Contingent Deferred Sales Charges

A CDSC may not be imposed on redemptions of Class A, Class A2 and Investor Class shares purchased at NAV through financial intermediaries or by persons that are affiliated with New York Life or its affiliates. Any applicable CDSC on Class A, Class A2 and Investor

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Class shares may be waived for redemptions made through a financial intermediary firm that has waived its finder’s fee or other similar compensation.

In addition, the CDSC on subject Class A, Class A2, Investor Class, Class B, Class C or Class C2 shares may be waived for: (i) withdrawals from qualified retirement plans and nonqualified deferred compensation plans resulting from separation of service, loans, hardship withdrawals, Qualified Domestic Relations Orders ("QDROs") and required excess contribution returns pursuant to applicable IRS rules; and Required Minimum Distributions (based on MainStay holdings only) for IRA and 403(b)(7) TSA participants in the year following the year in which such participant attains age 73. However, different rules relating to mandatory distributions apply to individuals who attained age 70 1/2 before 2020; (ii) withdrawals related to the termination of a retirement plan where no successor plan has been established; (iii) transfers within a retirement plan where the proceeds of the redemption are invested in any guaranteed investment contract written by New York Life or any of its affiliates, transfers to products offered within a retirement plan which uses NYLIM Service Company or an affiliate as the recordkeeper; as well as participant transfers or rollovers from a retirement plan to a MainStay IRA; (iv) required distributions by charitable trusts under Section 664 of the Internal Revenue Code for accounts held directly with a MainStay Fund; (v) redemptions following the death of the shareholder or the beneficiary of a living revocable trust or within one year (18 months with respect to Class A, Investor Class and Class C shares of the MainStay MacKay Short Duration High Yield Fund) following the disability of a shareholder occurring subsequent to the purchase of shares; (vi) redemptions under the Systematic Withdrawal Plan for accounts held directly with the Fund used to pay scheduled monthly premiums on insurance policies issued by New York Life or an affiliate; (vii) continuing, periodic systematic withdrawals within one year of the date of the initial purchase, under the Systematic Withdrawal Plan, up to an annual total of 10% of the value of a shareholder's Class A, Class A2, Investor Class, Class B, Class C or Class C2 shares in a Fund; (viii) redemptions by New York Life or any of its affiliates or by accounts managed by New York Life or any of its affiliates; (ix) redemptions effected by registered investment companies by virtue of transactions with a Fund; and (x) redemptions by shareholders of shares purchased with the proceeds of a settlement payment made in connection with the liquidation and dissolution of a limited partnership sponsored by New York Life or one of its affiliates.

The availability of contingent deferred sales charge waivers may depend on the particular financial intermediary or type of account through which you purchase or hold MainStay Fund shares. The MainStay Funds’ contingent deferred sales charge waivers disclosed in this Prospectus and the SAI are available for direct accounts and through financial intermediaries. The contingent deferred sales charge waivers available through certain other financial intermediaries are set forth in Appendix A – Intermediary-Specific Sales Charge Waivers and Discounts to this Prospectus. Please contact your financial intermediary regarding applicable sales charge waivers and information regarding the intermediary’s related policies and procedures.

For information about these considerations, call your financial adviser or the Transfer Agent toll free at 800-624-6782; see our website at newyorklifeinvestments.com/salescharges; and read the information under "Reduced Sales Charges on Class A, Class A2 and Investor Class Shares—Contingent Deferred Sales Charge, Class A, Class A2 and Investor Class Shares" in the SAI.

Rule 12b-1 Plans

Each MainStay Fund (except the MainStay Money Market Fund) has adopted a distribution plan pursuant to Rule 12b-1 under the 1940 Act for certain classes of shares pursuant to which distribution and/or service (12b-1) fees are paid to the Distributor. Rule 12b-1 fees are calculated and accrued daily and paid monthly. The Investor Class, Class A, Class A2 and Class R2 12b-1 plans provide for payment for distribution and/or service activities of up to 0.25% of the average daily net assets of the respective class. The Class B and Class C 12b-1 plans each provide for payment of 0.75% for distribution (0.25% for MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund) and 0.25% for service activities for a total 12b-1 fee of up to 1.00% of the average daily net assets of Class B and Class C shares, respectively (0.50% for MainStay MacKay California Tax Free Opportunities Fund, MainStay MacKay New York Tax Free Opportunities Fund, MainStay MacKay Strategic Municipal Allocation Fund and MainStay MacKay Tax Free Bond Fund). The Class C2 12b-1 plan provides for payment of 0.40% for distribution and 0.25% for service activities for a total 12b-1 fee of up to 0.65% of the average daily net assets of Class C2 shares. The Class R3 and SIMPLE Class 12b-1 plans each provide for payment of 0.25% for distribution and/or 0.25% for service activities for a total 12b-1 fee of up to 0.50% of the average daily net assets of Class R3 and SIMPLE Class shares, respectively. The distribution activities paid for by this distribution fee are those activities that are primarily intended to result in the sale of MainStay Fund shares. The service activities paid for by this service fee are personal shareholder services and maintenance of shareholder accounts. With respect to Class R2 and Class R3 shares, the portion of the 12b-1 fee dedicated to service activities is in addition to the 0.10% of annual net assets paid under the Class R2 and Class R3 Shareholder Services Plans, as discussed in the section entitled "Shareholder Services Plans." The Distributor may pay all or a portion of the 12b-1 fee to your investment professional. Because 12b-1 fees are ongoing, over time they will increase the cost of an investment in the MainStay Fund and may cost more than certain types of sales charges.

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Shareholder Services Plans

Each MainStay Fund that offers Class R1, Class R2 or Class R3 shares has adopted a Shareholder Services Plan with respect to those classes. Under the terms of the Shareholder Services Plans, each MainStay Fund's Class R1, Class R2 or Class R3 shares pay New York Life Investments, its affiliates or independent third-party service providers, as compensation for services rendered to the shareholders of the Class R1, Class R2 or Class R3 shares, a shareholder service fee at the rate of 0.10% on an annualized basis of the average daily net assets of Class R1, Class R2 or Class R3 shares of such MainStay Fund.

Pursuant to the Shareholder Services Plans, each MainStay Fund's Class R1, Class R2 or Class R3 shares may pay for shareholder services or account maintenance services, including assistance in establishing and maintaining shareholder accounts, processing purchase and redemption orders, communicating periodically with shareholders and assisting shareholders who have questions or other needs relating to their account. Because service fees are ongoing, over time they will increase the cost of an investment in the MainStay Fund and may cost more than certain types of sales charges. With respect to the Class R2 and R3 shares, these services and fees are in addition to those services and fees that may be provided under the Class R2 or Class R3 12b-1 plan.

Small Account Fee

Several of the MainStay Funds have a relatively large number of shareholders with small account balances. Small accounts increase the transfer agency expenses borne by the Funds. In an effort to reduce total transfer agency expenses, the MainStay Funds (except the MainStay ETF Asset Allocation Funds) have implemented a small account fee. Each shareholder with an account balance of less than $1,000 ($5,000 for Class A share accounts) will be charged an annual per account fee of $20 (assessed semi-annually, as discussed below). The fee may be deducted directly from your account balance. This small account fee will not apply to certain types of accounts including:

· accounts held by employees of New York Life and its subsidiaries and their employees, officers, directors or agents or former employees (and immediate family members);

· Class B share, Class I share, Class R1 share, Class R2 share, Class R3 share, Class R6 share and Class P share accounts, retirement plan services bundled accounts and investment-only retirement accounts;

· accounts with active AutoInvest plans where the MainStay Funds deduct funds directly from the client's checking or savings account;

· New York Life Investments SIMPLE IRA Plan Accounts and SEP IRA Accounts that have been funded/established for less than 1 year;

· certain 403(b)(7) accounts;

· accounts serviced by unaffiliated financial intermediary firms or third-party administrators (other than New York Life Investments SIMPLE IRA Plan Accounts);

· certain Investor Class accounts where the small account balance is due solely to the conversion from Class B, Class C or Class C2 shares; and

· Investors who obtained their Class A shares through certain reorganizations.

This small account fee will be deducted in $10 increments on or about March 1st and September 1st of each year. For accounts with balances of less than $10, the remaining balance will be deducted and the account will be closed. The MainStay Funds may, from time to time, consider and implement additional measures to increase the average shareholder account size and/or otherwise reduce the cost of transfer agency services. Please contact the MainStay Funds by calling toll-free 800-624-6782 for more information.

Financial intermediary firms and their associated financial advisers are paid in different ways for the services they provide to the MainStay Funds and shareholders. Such compensation may vary depending upon the financial intermediary firm, the MainStay Fund sold, the amount invested, the share class sold, the amount of time that shares are held and/or the services provided by the particular financial intermediary firm.

The Distributor will pay sales concessions to financial intermediary firms, as described in the tables under “Information on Sales Charges” above, on the purchase price of Investor Class, Class A or Class A2 shares sold subject to a sales charge. The Distributor retains the difference, if any, between the sales charge that you pay and the portion that it pays to financial intermediary firms as a sales concession. The Distributor and/or an affiliate, from its/their own resources, also may pay a finder’s fee or other compensation up to 1.00% of the purchase price of Investor Class, Class A or Class A2 shares, sold at NAV, to financial intermediary firms at the time of sale. The Distributor may pay a sales concession of up to 1.00% on purchases of Class C or Class C2 shares to financial intermediary firms at the time of sale.

For share classes that have adopted a 12b-1 plan, the Distributor will also pay, pursuant to the 12b-1 plan, distribution-related and other service fees to qualified financial intermediary firms for providing certain services.

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Shareholder Guide

In addition to the payments described above, the Distributor and/or an affiliate will pay from its/their own resources additional fees to certain financial intermediary firms, including an affiliated broker/dealer, in connection with the sale of any class of MainStay Fund shares (other than Class R6) and/or shareholder or account servicing arrangements. The amount paid to financial intermediary firms pursuant to these sales and/or servicing fee arrangements varies and may involve payments of up to 0.25% on new sales and/or up to 0.35% annually on assets held or fixed dollar amounts according to the terms of the agreement between the Distributor and/or its affiliate and the financial intermediary. The Distributor or an affiliate may make these payments based on factors including, but not limited to, the distribution potential of the financial intermediary, the types of products and programs offered by the financial intermediary, the level and/or type of marketing and administrative support provided by the financial intermediary, the level of assets attributable to and/or sales by the financial intermediary and the quality of the overall relationship with the financial intermediary. Such payments may qualify a MainStay Fund for preferred status with the financial intermediary receiving the payments or provide the representatives of the Distributor with access to representatives of the financial intermediary’s sales force, in some cases on a preferential basis over the mutual funds and/or representatives of the Funds’ competitors.

The Distributor, from its own resources or from those of an affiliate, also may reimburse financial intermediary firms in connection with their marketing activities supporting the MainStay Funds. To the extent permitted under applicable SEC and Financial Industry Regulatory Authority (“FINRA”) rules and other applicable laws and regulations, the Distributor or an affiliate may sponsor training or informational meetings or provide other non-monetary benefits for financial intermediary firms and their associated financial advisers and may make other payments or allow other promotional incentives or payments to financial intermediaries.

Wholesaler representatives of the Distributor communicate with financial intermediary firms on a regular basis to educate their financial advisers about the MainStay Funds and to encourage the advisers to recommend the purchase of MainStay Fund shares to their clients. The Distributor, from its own resources or from those of an affiliate, may absorb the costs and expenses associated with the marketing efforts of these firms and financial advisers, which may include travel, lodging, sponsorship at educational seminars and conferences, entertainment and meals to the extent permitted by law and FINRA rules. The Distributor, from its own resources or from those of an affiliate, provides compensation to its wholesaler representatives for their sales efforts in promoting sales of the MainStay Funds, which may vary based on the MainStay Funds being promoted and/or which financial intermediary firms and/or financial advisers are involved in selling MainStay Fund shares or are listed on MainStay Fund accounts.

To the extent that financial intermediaries receiving payments from the Distributor or an affiliate sell more shares of the MainStay Funds or retain more shares of the MainStay Funds for their clients’ accounts, New York Life Investments and its affiliates benefit from the incremental management and other fees they receive with respect to those assets.

In addition to the payments described above, NYLIM Service Company or an affiliate may make payments to financial intermediary firms that provide sub-transfer agency and other administrative services in addition to supporting distribution of the MainStay Funds. NYLIM Service Company uses a portion of the transfer agent fees it receives from the MainStay Funds to make these sub-transfer agency and other administrative payments. To the extent that the fee amounts payable by NYLIM Service Company or an affiliate for such sub-transfer agency and other administrative services exceed the corresponding transfer agent fees that the MainStay Funds pay to NYLIM Service Company, then NYLIM Service Company or an affiliate will pay the difference from its own resources. In connection with these arrangements, NYLIM Service Company may retain a portion of the fees for the sub-transfer agency oversight, support and administrative services it provides.

For Class R6 shares, no compensation, administrative payments, sub-transfer agency payments or service payments are paid to financial intermediary firms from MainStay Fund assets or the Distributor’s or an affiliate’s resources. The Distributor or an affiliate may pay de minimis amounts to intermediaries for setup, connectivity or other technological expenses. Class R6 shares do not provide for the payment of sales charges, Rule 12b-1 fees, or other compensation to financial intermediaries for their efforts in assisting in the sale of, or in selling the MainStay Fund’s shares.

Although financial firms that sell MainStay Fund shares may execute brokerage transactions for a MainStay Fund’s portfolio, the MainStay Funds, New York Life Investments and the Subadvisors do not consider the sale of MainStay Fund shares as a factor when choosing financial firms to effect portfolio transactions for the MainStay Funds.

The types and amounts of payments described above can be significant to the financial intermediary. Payments made from the Distributor’s or an affiliate’s resources do not increase the price or decrease the amount or value of the shares you purchase. However, if investment advisers, distributors or affiliates of mutual funds make such payments in differing amounts, financial intermediary firms and their financial advisers may have financial incentives and be subject to conflicts of interest for recommending a particular mutual fund or a particular share class of that fund over other mutual funds. For example, payments made by the Distributor or an affiliate, as described above, may be used by the financial intermediary firm to reduce or eliminate transaction charges associated with purchases of MainStay Fund shares. Payments made from the Distributor’s or an affiliate’s own resources are not reflected in tables in the “Fees and Expenses of the Fund” sections of the MainStay Funds’ Prospectuses because the payments are not made by the MainStay Funds.

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Shareholder Guide

For more information regarding the types of compensation described above, see the SAI or consult with your financial intermediary firm or financial adviser. You should also review carefully any disclosure by your financial intermediary firm as to compensation received by that firm and/or your financial adviser.

Investor Class, Class A or Class C Shares

Return your completed MainStay Funds application in good order with a check payable to the MainStay Funds for the amount of your investment to your financial adviser or directly to MainStay Funds, P.O. Box 219003, Kansas City, Missouri 64121-9000. Alternatively, you may choose to have your initial deposit processed via ACH from your bank account. You can do this by selecting the initial deposit via ACH option and submitting bank information on your application. Please note that if you select Class A shares on your application and you are not eligible to invest in Class A shares, we will treat your application as being in good order but will invest you in Investor Class shares of the same MainStay Fund provided Investor Class shares are available through your intermediary if you are not purchasing shares directly from the MainStay Funds. Similarly, if you select Investor Class shares and you are eligible to invest in Class A shares we will treat your application as being in good order, but will invest you in Class A shares of the same MainStay Fund.

Class A2 Shares

Class A2 shares are available only through certain financial intermediary firms. The financial intermediary firm will assist you with opening an account.

Class I, Class R1, Class R2, Class R3, Class R6 and SIMPLE Class Shares

If you are participating in a company savings plan, such as a 401(k) plan, profit sharing plan, defined benefit plan, Keogh or other employee-directed plan, your company will provide you with the information you need to open an account and buy or sell Class I, Class R1, Class R2, Class R3, Class R6 or SIMPLE Class shares of the MainStay Funds.

If you are investing through a financial intermediary firm, the financial intermediary firm will assist you with opening an account.

Class C2 Shares

Class C2 shares are available only through certain financial intermediary firms. The financial intermediary firm will assist you with opening an account.

Class P Shares

Return your completed MainStay Funds application in good order with a check payable to the MainStay Funds for the amount of your investment directly to MainStay Funds, P.O. Box 219003, Kansas City, Missouri 64121-9000. Alternatively, you may choose to have your initial deposit processed via ACH from your bank account. You can do this by selecting the initial deposit via ACH option and submitting bank information on your application.

All Classes

You buy shares at NAV (plus, for Investor Class, Class A and Class A2 shares, any applicable front-end sales charge). NAV is generally calculated by each MainStay Fund as of the Fund’s close (usually 4:00 pm Eastern time) on the Exchange every day the Exchange is open. The MainStay Funds do not usually calculate their NAVs on days when the Exchange is scheduled to be closed. When you buy shares, you must pay the NAV next calculated after we receive your purchase request in good order. Alternatively, the MainStay Funds have arrangements with certain financial intermediary firms whereby purchase requests through these entities are considered received in good order when received by the financial intermediary firm together with the purchase price of the shares ordered. The order will then be priced at a MainStay Fund's NAV next computed after receipt in good order of the purchase request by these entities. Such financial intermediary firms are responsible for timely and accurately transmitting the purchase request to the MainStay Funds.

If the Exchange is closed due to inclement weather, technology problems or any other reason on a day it would normally be open for business, or the Exchange has an unscheduled early closing on a day it has opened for business, each MainStay Fund reserves the right to treat such day as a business day and accept purchase and redemption orders until, and calculate its NAV as of, the normally scheduled close of regular trading on the NYSE for that day, so long as New York Life Investments believes there generally remains an adequate market to obtain reliable and accurate market quotations. On any business day when the Securities Industry and Financial Markets Association recommends that the bond markets close trading early, each MainStay Fund reserves the right to close at such

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earlier closing time, and therefore accept purchase and redemption orders until, and calculate a Fund’s NAV as of, such earlier closing time.

When you open your account, you may also want to choose certain buying and selling options, including transactions by wire. In most cases, these choices can be made later in writing, but it may be quicker and more convenient to decide on them when you open your account. Please note that your bank may charge a fee for wire transfers.

To help the government fight the funding of terrorism and money laundering activities, federal law requires all financial institutions to obtain, verify and record information that identifies each person who opens a new account and to determine whether such person's name appears on government lists of known or suspected terrorists and terrorist organizations. As a result, the MainStay Funds, or your financial adviser on their behalf, must obtain the following information for each person who opens a new account:

· Name;

· Date of birth (for individuals);

· Residential or business street address (although post office boxes are still permitted for mailing); and

· Social security number or taxpayer identification number.

You may also be asked for a copy of your driver's license, passport or other identifying document in order to verify your identity. In addition, it may be necessary to verify your identity by cross-referencing your identification information with a consumer report or other electronic database. Additional information may be required to open accounts for corporations and other entities. Certain information regarding beneficial ownership will be verified, including information about the identity of beneficial owners of such entities.

Federal law prohibits the MainStay Funds and other financial institutions from opening a new account unless they receive the minimum identifying information listed above.