Prospectus | August 28, 2023

Not FDIC Insured. May lose value. No bank guarantee.

Contents

 

 

 

 

 

 

Investment objective

The fund’s investment objective is to provide current income while seeking to maintain low volatility of principal.

The fund’s investment objective is “non‑fundamental.” This means that it may be changed by the fund’s board of trustees without shareholder approval.

Principal investment strategies

The fund seeks to achieve its investment objective by investing in a diversified portfolio of short duration, high quality money market instruments and other fixed income securities of governmental, municipal and private issuers, which may include short-term obligations of the US government and its instrumentalities; repurchase agreements; obligations of issuers in the financial services group of industries; commercial paper, other corporate obligations, and asset-backed securities; and municipal money market instruments. The fund may invest in the securities of money market funds, including those advised by UBS Asset Management (Americas) Inc. (“UBS AM”).

The fund may invest in securities of any maturity, but will generally limit its weighted average portfolio duration to one year or less. Duration is a measure used to determine the sensitivity of a security’s price to changes in interest rates. Duration incorporates a bond’s yield, coupon interest payments, final maturity, call and put features and prepayment exposure into one measure, with a higher duration indicating greater sensitivity to interest rate changes. For example, if a portfolio has a duration of two years, and interest rates increase (fall) by 1%, the portfolio should decline (increase) in value by approximately 2%. However, duration may not accurately reflect the true interest rate sensitivity of

instruments held by the fund and, therefore the fund’s exposure to changes in interest rates.

Although the use of derivatives is not a principal strategy of the fund, it may use derivative instruments such as futures, forwards, options, and/or swaps for risk management purposes or as part of the fund’s investment strategies.

The fund may engage in securities lending to the extent permitted by law.

The fund is not a money market fund and does not seek to maintain a stable NAV. As a result, the value of your investment in the fund may change.

Securities selection

UBS AM serves as the fund’s investment advisor. UBS AM’s investment process employs a rigorous valuation and research framework, combining top‑down macroeconomic and quantitative research with issuer level credit analysis. This dynamic approach allows UBS AM to exploit diversified sources of return, which UBS AM believes is key to delivering consistent performance over time.

The top‑down process involves formulation of broad investment views and views regarding macroeconomic trends. UBS AM’s views on the direction of interest rates, yield curve shape, sectors, and volatility help formulate final portfolio positioning.

After establishing the top‑down strategy, the portfolio management team, working closely with UBS AM’s research analysts, uses rigorous credit/structure analysis and relative pricing to choose securities that it believes have superior risk/return characteristics. UBS AM integrates risk management throughout its investment process.

UBS AM considers safety of principal and liquidity in selecting securities for the fund and thus may not buy securities that pay the highest yield.

The fund is classified by UBS AM as an “ESG-integrated” fund. The fund’s investment process integrates material sustainability and/or environmental, social and governance (“ESG”) considerations into the research process for all portfolio investments and portfolio holdings, except repurchase agreements with certain counterparties and except asset-backed and mortgage-backed securities. ESG integration is driven by taking into account material sustainability and/or ESG risks which could impact investment returns, rather than being driven by specific ethical principles or norms. The analysis of material sustainability and/or ESG considerations can include many different aspects, including, for example, the carbon footprint, employee health and well-being, supply chain management, fair customer treatment and governance processes of a company. The fund’s portfolio managers may still invest in securities without respect to sustainability and/or ESG considerations or in securities which present sustainability and/or ESG risks, including where the portfolio managers believe the potential compensation outweighs the risks identified.

Principal risks

All investments carry a certain amount of risk, and the fund cannot guarantee that it will achieve its investment objective. You may lose money by investing in the fund. An investment in the fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The principal risks presented by an investment in the fund are described below. Other risks of investing in the fund, along with further details about some of the risks described below, are discussed in the fund’s

SAI. Information on how you can obtain the SAI is on the back cover of this prospectus.

Credit risk. Credit risk is the risk that the issuer or guarantor of a fixed income security, or the counterparty to or guarantor of a derivative contract or transaction, is unable or unwilling to meet its financial obligations. Even if an issuer or counterparty does not default on a payment, an investment’s value may decline if the market believes that the issuer or counterparty has become less able, or less willing, to make payments on time. Moreover, in a rising interest rate environment, the risk that such issuer or guarantor may default on its obligations is heightened. Even high quality investments are subject to some credit risk. However, credit risk is greater for lower quality investments than for investments that are higher quality. Fixed income securities that are not investment grade, which are commonly known as “junk bonds,” involve high credit risk and are considered speculative. Some of these low quality securities may go into default. Low quality fixed income securities may fluctuate in value more than higher quality bonds and, during periods of market volatility, may be more difficult to sell at the time and price the fund desires.

Financial services sector risk. Investments of the fund in the financial services group of industries or sectors may be particularly affected by economic cycles, business developments, interest rate changes and regulatory changes. For example, declining economic and business conditions can disproportionately impact companies in the financial services sector due to increased defaults on payments by borrowers. Interest rate increases can also adversely affect the financial services sector by increasing the cost of capital available for financial services companies. In addition, financial services companies are heavily regulated by governmental entities and, as a result, political and regulatory

changes can affect the operations and financial results of such companies, potentially imposing additional costs and possibly restricting the businesses in which those companies may engage.

Concentration risk. The fund will invest a significant portion of its assets in securities issued by companies in the financial services group of industries or sectors, including US banking, non‑US banking, broker-dealers, insurance companies, finance companies (e.g., automobile finance) and related asset-backed securities. As a result, the fund’s performance will be significantly impacted, both positively and negatively, by developments in the financial services sector, and the fund will be more susceptible to such developments than other funds that do not concentrate their investments.

Interest rate risk. The value of bonds and other fixed income securities generally can be expected to fall when short-term interest rates rise and to rise when short-term interest rates fall. Interest rate risk is the risk that interest rates will rise, so that the value of the fund’s investments in bonds and other fixed income securities will fall. Duration is a measure of the fund’s exposure to interest rate risk. A longer duration means that the changes in market interest rates will generally have a larger effect on the fund’s market value.

Interest rate risk is the primary source of risk for US government securities and usually for other very high quality bonds. The impact of changes in the general level of interest rates on lower quality bonds may be greater or less than the impact on higher quality bonds.

The fund may face a heightened level of interest rate risk due to certain changes in monetary policy, such as certain types of interest rate changes by the Federal Reserve. The risks associated with changing interest

rates may have unpredictable effects on the markets and the fund’s investments. A sudden or unpredictable increase in interest rates may cause volatility in the market and may decrease liquidity in the money market securities markets, making it harder for the fund to sell its money market investments at an advantageous time. Decreased market liquidity also may make it more difficult to value some or all of the fund’s money market securities holdings.

Some corporate and municipal bonds, particularly those issued at relatively high interest rates, provide that the issuer may repay them earlier than the maturity date. The issuers of these bonds are most likely to exercise these “call” provisions if prevailing interest rates are lower than they were when the bonds were issued. The fund then may have to reinvest the repayments at lower interest rates. Bonds subject to call provisions also may not benefit fully from the rise in value that generally occurs for bonds when interest rates fall.

Liquidity risk. The risk that investments cannot be readily sold at the desired time or price, and the fund may have to accept a lower price or may not be able to sell the security at all. An inability to sell securities can adversely affect the fund’s value or prevent the fund from taking advantage of other investment opportunities. Liquid portfolio investments may become illiquid or less liquid after purchase by the fund due to low trading volume, adverse investor perceptions and/or other market developments. In recent years, the number and capacity of dealers that make markets in fixed income securities has decreased. Consequently, the decline in dealers engaging in market making trading activities may increase liquidity risk, which can be more pronounced in periods of market turmoil or when prices of securities are negatively impacted by rapid or unexpected changes in interest rates. Liquidity risk may be magnified in a rising interest rate environment or when investor redemptions

from fixed income funds may be higher than normal, causing increased supply in the market due to selling activity. Liquidity risk includes the risk that the fund will experience significant net redemptions at a time when it cannot find willing buyers for its portfolio securities or can only sell its portfolio securities at a material loss, making it more difficult for the fund to meet redemption requests.

Management risk. There is the risk that the investment strategies, techniques and risk analyses employed by the advisor may not produce the desired results. The investment advisor may be incorrect in its assessment of a particular security or other investment or assessment of market, interest rate or other trends, which can result in losses to the fund.

Market risk. The risk that the market value of the fund’s investments will fluctuate as the stock and fixed-income markets fluctuate. Market risk may affect a single issuer, industry or sector of the economy, or it may affect the market as a whole. In addition, turbulence in financial markets and reduced liquidity in equity and/or fixed-income markets may negatively affect the fund. Global economies and financial markets are becoming increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. Events such as war, acts of terrorism, natural disasters, recessions, rapid inflation, the imposition of international sanctions, pandemics or other public health threats could also significantly impact the fund and its investments. These risks may be magnified if certain events or developments adversely interrupt the global supply chain, and could affect companies worldwide.

Mortgage- and asset-backed securities risk. The fund may invest in mortgage- and asset-backed securities that are subject to prepayment or call risk,

which is the risk that the borrower’s payments may be received earlier or later than expected due to changes in prepayment rates on underlying loans. Faster prepayments often happen when interest rates are falling. As a result, the fund may reinvest these early payments at lower interest rates, thereby reducing the fund’s income. Conversely, when interest rates rise, prepayments may happen more slowly, causing the security to lengthen in duration. Longer duration securities tend to be more volatile. Securities may be prepaid at a price less than the original purchase value. An unexpectedly high rate of defaults on the mortgages held by a mortgage pool may adversely affect the value of mortgage-backed securities and could result in losses to the fund.

Floating or variable rate securities risk. Floating or variable rate securities bear interest at rates that are not fixed but that vary with changes in specified market rates or indices. The market value of floating rate and variable rate securities generally fluctuates less than the market value of fixed rate obligations. Accordingly, as interest rates decrease or increase, the potential for capital appreciation or capital depreciation is less than for fixed rate obligations. Although floating or variable rate securities are generally less sensitive to interest rate risk than fixed rate securities, they are subject to credit, liquidity and market risk.

NAV risk. The fund is not a money market fund, does not attempt to maintain a stable NAV, and is not subject to the rules that govern the quality, maturity, liquidity and other features of securities that money market funds may purchase. Under normal conditions, the fund’s investments would be more susceptible than a money market fund’s investments to interest rate risk, valuation risk, credit risk, and other risks relevant to the fund’s investments. The fund’s NAV per share will fluctuate. Because the fund is not a money market fund, it does not qualify for the special money market fund tax treatment or tax accounting methods under US Treasury regulations.

Prepayment risk. Payments on bonds and other fixed income securities that are backed by mortgage loans or similar assets may be received earlier or later than expected due to changes in the rate at which the underlying loans are prepaid. Faster prepayments often happen when market interest rates are falling. As a result, the fund may need to reinvest these early payments at those lower interest rates, thus reducing its income. Conversely, when interest rates rise, prepayments may happen more slowly, causing the underlying loans to be outstanding for a longer time than anticipated. This can cause the market value of the security to fall because the market may view its interest rate as too low for a longer term investment.

Valuation risk. During periods of reduced market liquidity or in the absence of readily available market quotations for securities or instruments in the fund’s portfolio, the ability of the fund to value the fund’s investments becomes more difficult and the judgment of the fund’s investment advisor may play a greater role in the valuation of the fund’s investments due to reduced availability of reliable objective pricing data. Consequently, while such determinations may be made in good faith, it may nevertheless be more difficult for the fund to accurately assign a daily value to such investments.

Variable rate demand obligations risk. Variable rate demand obligations are floating rate securities that combine an interest in a long-term bond, such as municipal debt, with a right to demand payment before maturity from a bank or other financial institution. If the bank or financial institution is unable to pay, the fund may lose money. The absence of an active secondary market for certain variable and floating rate obligations could make it difficult to dispose of these instruments, which could result in a loss.

Municipal securities risk. Municipal securities are subject to interest rate, credit, illiquidity, market and

political risks. The ability of a municipal issuer to make payments and the value of municipal securities can be affected by uncertainties in the municipal securities market, including litigation, the strength of the local or national economy, the issuer’s ability to raise revenues through tax or other means, the bankruptcy of the issuer affecting the rights of municipal securities holders and budgetary constraints of local, state and federal governments upon which the issuer may be relying for funding. Municipal securities and issuers of municipal securities may be more susceptible to downgrade, default and bankruptcy during periods of economic stress. In addition, the municipal securities market can be significantly affected by political changes, including legislation or proposals at either the state or the federal level to eliminate or limit the tax‑exempt status of municipal security interest. Similarly, reductions in tax rates may make municipal securities less attractive in comparison to taxable securities. Legislatures also may be unable or unwilling to appropriate funds needed to pay municipal security obligations. These events can cause the value of the municipal securities held by the fund to fall. In addition, third-party credit quality or liquidity enhancements are frequently a characteristic of the structure of certain types of municipal securities. Problems encountered by such third-parties (such as issues negatively impacting a municipal security insurer or bank issuing a liquidity enhancement facility) may negatively impact a municipal security even though the related municipal issuer is not experiencing problems. Municipal bonds secured by revenues from public housing authorities may be subject to additional uncertainties relating to the possibility that proceeds may exceed supply of available mortgages to be purchased by public housing authorities, resulting in early retirement of bonds, or that homeowner repayments will create an irregular cash flow.

Zero coupon securities risk. Zero coupon securities are securities on which no periodic interest payments

are made but instead are sold at a deep discount from their face value. Zero coupon securities are generally more sensitive to changes in interest rates than debt obligations of comparable maturities that make current interest payments. This means that when interest rates fall, the value of zero coupon securities generally rises more rapidly than securities paying interest on a current basis. However, when interest rates rise, their value generally falls more dramatically.

US government securities risk. Credit risk is the risk that the issuer will not make principal or interest payments when they are due. There are different types of US government securities with different relative levels of credit risk depending on the nature of the particular government support for that security. US government securities may be supported by (1) the full faith and credit of the US; (2) the ability of the issuer to borrow from the US Treasury; (3) the credit of the issuing agency, instrumentality or government-sponsored entity; (4) pools of assets (e.g., mortgage-backed securities); or (5) the US in some other way. In some cases, there is even the risk of default. For example, for mortgage-backed securities there is the risk those assets will decrease in value below the face value of the security. Similarly, for certain agency-issued securities there is no guarantee the US government will support the agency if it is unable to meet its obligations. Further, the US government and its agencies and instrumentalities do not guarantee the market value of their securities; consequently, the value of such securities will fluctuate. This may be the case especially when there is any controversy or ongoing uncertainty regarding the status of negotiations in the US Congress to increase the statutory debt ceiling. If the US Congress is unable to negotiate an adjustment to the statutory debt ceiling, there is also the risk that the US government may default on payments on certain US government securities, including those held by the fund, which could have a material negative impact on the fund.

Repurchase agreements risk. Repurchase agreements carry certain risks not associated with direct investments in securities, including a possible decline in the market value of the underlying obligations. If their value becomes less than the repurchase price, plus any agreed-upon additional amount, the counterparty must provide additional collateral so that at all times the collateral is at least equal to the repurchase price plus any agreed-upon additional amount. Repurchase agreements involving obligations other than US government securities (such as commercial paper, corporate bonds, mortgage loans and equities) may be subject to special risks and may not have the benefit of certain protections in the event of the counterparty’s insolvency. If the seller or guarantor becomes insolvent, the fund may suffer delays, costs and possible losses in connection with the disposition of collateral.

money market funds. At the same time, the fund would continue to pay its own management fees and expenses with respect to all of its direct investments.

Sovereign debt risk: Sovereign debt includes bonds that are issued by foreign governments or their agencies, instrumentalities or political subdivisions or by foreign central banks. Sovereign debt also may be issued by quasi-governmental entities that are owned by foreign governments but are not backed by their full faith and credit or general taxing powers. Investment in sovereign debt involves special risks. The issuer of the debt or the governmental authorities that control the repayment of the debt may be unable or unwilling to repay principal and/or interest when due in accordance with the terms of such debt, and the fund may have limited legal recourse in the event of a default. In addition, the issuer of sovereign debt may be unable or unwilling to repay due to the imposition of international sanctions and other similar measures.

Foreign investing risk. The fund may invest in foreign instruments that are denominated in US dollars or hedged to US dollars. Foreign investing may involve risks relating to political, social and economic developments abroad, such as the imposition of international sanctions and other similar measures, to a greater extent than investing in the securities of US issuers. Foreign investments may also be subject to risk of loss because of more or less foreign government regulation, less public information and less stringent investor protections and disclosure standards. In addition, there are differences between US and foreign regulatory requirements and market practices.

Derivatives risk. In addition to the risks associated with the underlying assets, reference rates or indices on which derivatives are based, derivatives are subject to risks different from, and possibly greater than, those of direct investments in securities and other

instruments. If the investment advisor incorrectly forecasts the value of securities, currencies, interest rates, or other economic factors in using derivatives, the fund might have been in a better position had it not entered into the derivatives. While some strategies involving derivatives are designed to protect against the risk of loss, this use of derivatives may also reduce the opportunity for gain or even result in losses by offsetting favorable price movements in other fund investments. Gains or losses may be substantial, and in some cases losses may exceed the amount of the fund’s initial investment. In addition, if the fund has insufficient cash to meet daily variation margin requirements, it may have to sell securities from its portfolio at a time when it may be disadvantageous to do so. Some derivatives tend to be more volatile than other investments, resulting in larger gains or losses in response to market changes. In October 2020, the SEC adopted Rule 18f-4 related to the use of derivatives, reverse repurchase agreements and certain other transactions by registered investment companies and rescinded and withdrew certain guidance of the SEC and its staff regarding asset segregation and cover transactions. Under Rule 18f-4, the fund has adopted a derivatives risk management program and appointed a derivatives risk manager that manages the program and communicates to the board of the fund. Compliance with Rule 18f-4 may increase the cost of the fund’s investments and cost of doing business, which could adversely affect investors. Derivatives also involve the risk of mispricing or other improper valuation; the risk that changes in the value of a derivative may not correlate as anticipated with the underlying asset, rate, index or overall securities markets, thereby reducing their effectiveness; credit risk; counterparty risk (the risk that the other party to a swap agreement or other derivative will not fulfill its contractual obligations, whether because of bankruptcy or other default); liquidity risk (the possible lack of a secondary market for derivatives and the resulting inability

of the fund to sell or otherwise close out the derivatives at a favorable price, if at all); and interest rate risk (some derivatives are more sensitive to interest rate changes and market price fluctuations). Finally, the fund’s use of derivatives may cause the fund to realize higher amounts of short-term capital gains (generally taxed at ordinary income tax rates) than if the fund had not used such instruments.

Additional (non-principal) risks

High yield securities (“junk bonds”) risk. National rating agencies typically rate bonds and other fixed income securities. These ratings generally assess the ability of the issuer to pay principal and interest. Issuers of securities that are rated below investment grade (i.e., lower than Baa3/BBB‑ and their unrated equivalents) are typically in poorer financial health, and lower-rated securities and their unrated equivalents may be (1) subject to a greater risk of loss of principal and non‑payment of interest (including default by the issuer); (2) subject to greater price volatility; and (3) less liquid than investment grade securities. High yield securities are particularly sensitive to interest rates, and the prices of such securities may be more vulnerable to bad economic news, or even the expectation of bad news, than higher rated or investment grade bonds and other fixed income securities. In addition, high yield securities are often thinly traded and may be more difficult to sell and value accurately than higher rated fixed income securities of a similar maturity.

Securities lending risk. Securities lending involves the lending of portfolio securities owned by the fund to qualified broker-dealers and financial institutions. When lending portfolio securities, the fund initially will require the borrower to provide the fund with collateral, most commonly cash, which the fund will invest. Although the fund invests this collateral in a conservative manner, it is possible that it could lose money from such an investment or fail to earn sufficient income from its investment to cover the fee or rebate that it has agreed to pay the borrower. Loans of securities also involve a risk that the borrower may fail to return the securities

or deliver the proper amount of collateral, which may result in a loss to the fund. In addition, in the event of bankruptcy of the borrower, the fund could experience losses or delays in recovering the loaned securities. In some cases, these risks may be mitigated by an indemnification provided by the fund’s lending agent.

Cybersecurity risk. The fund, like other business organizations, is susceptible to operational, information security and related risks through breaches in cybersecurity. In general, cybersecurity failures or breaches of the fund or its service providers or the issuers of securities in which the fund invests may result from deliberate attacks or unintentional events and may arise from external or internal sources. Cybersecurity breaches may involve unauthorized access to the fund’s digital information systems (e.g., through “hacking” or malicious software coding), but may also result from outside attacks such as denial-of-service attacks (i.e., efforts to make network services unavailable to intended users). Cybersecurity failures or breaches affecting the fund’s investment advisor or any other service providers (including, but not limited to, fund accountants, custodians, transfer agents and financial intermediaries) have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, interference with the fund’s ability to calculate its net asset value, impediments to trading, the inability of fund shareholders to transact business, destruction to equipment and systems, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs and/or additional compliance costs. In addition, substantial costs may be incurred in order to prevent any cybersecurity breaches in the future.

    

Flexible pricing

The fund offers one class of shares in this prospectus—Class I. (Class A and P shares of the fund are offered in a separate prospectus.) Class I shares are available only to certain types of investors. Investments must be denominated in US dollars.

Class I shares

Shareholders pay no front‑end or deferred sales charges on Class I shares. Only specific types of investors can purchase Class I shares.

The following investors are eligible to purchase Class I shares:

 

 

 

UBS AM (US) may waive the investment minimum in its discretion. The fund may change its minimum investment requirements at any time.

If your fund account balance has fallen below $10 million, or $2.5 million with respect to foundations, endowments and religious and other charitable organizations described in Section 501(c) of the Internal Revenue Code, UBS AM reserves the right

to reject your purchase order to add to the account unless the account balance will be at least $10 million, or $2.5 million, respectively, after that purchase.

Class I shares do not pay ongoing 12b‑1 distribution or service fees.

Buying shares

You can buy fund shares through a financial intermediary with which UBS AM (US) has a dealer agreement or through the fund’s transfer agent as described below.

The fund and UBS AM (US) reserve the right to reject a purchase order or suspend the offering of shares.

Additional compensation to financial institution(s)

UBS AM (US) or UBS AM may pay compensation, out of UBS AM’s profits and not as an additional charge to the fund, to certain financial institutions (which may include banks, securities dealers and other industry professionals) for the sale and/or distribution of fund shares or the retention and/or servicing of fund investors and fund shares. These payments are often referred to as “revenue sharing.” Revenue sharing payments are paid in addition to any record keeping or sub‑transfer agency fees payable by the fund, or other fees described in the fee tables or elsewhere in the prospectus or SAI. Revenue sharing payments are paid from UBS AM’s own resources and not as an additional charge to the fund.

The level of revenue sharing payments made to financial institutions may be a fixed fee or based upon one or more of the following factors: gross sales, current assets and/or number of accounts of

the fund attributable to the financial institution, or other factors as agreed to by UBS AM and the financial institution or any combination thereof. The amount of the revenue share may be different for different financial institutions. For specific information about revenue sharing arrangements for a particular financial institution please also see the SAI.

In some circumstances, revenue sharing payments may create an incentive for a financial institution, its employees or associated persons to recommend or sell shares of the fund to you. You should consult with a representative from the intermediary and review carefully any disclosure by the financial institution as to compensation received.

Minimum investments:

Class I Shares:

 

The fund may waive or reduce/change these amounts for (or as otherwise noted in the prospectus):

 

 

UBS AM (US) may waive the investment minimum in its discretion. The fund may change its minimum investment requirements at any time.

Selling shares

You can sell your fund shares at any time. If you own more than one class of shares, you should specify which class you want to sell. If you do not, the fund will assume that you want to sell shares in the following order: Class A (offered in a separate

prospectus with Class P shares), then Class P (offered in a separate prospectus with Class A shares) and last, Class I. If you want to sell shares that you purchased recently, the fund may delay payment until it verifies that it has received good payment. Also, if conditions exist that make cash payments undesirable, the fund reserves the right to honor any request for redemption by making payment in whole or in part in securities, to the extent permitted under applicable law. Additional information is available in the SAI.

If you hold your shares through a financial intermediary, you can sell shares by contacting your intermediary. The fund typically expects to pay sale proceeds to redeeming shareholders within 1-2 business days following receipt of a shareholder redemption order for those payments made to your account held with a financial institution; however, the fund may take up to 7 business days to pay sale proceeds. For sale proceeds that are paid directly to a shareholder by the fund, the fund typically expects to pay sales proceeds by wire, ACH, or mailing a check to redeeming shareholders within 1 business day following receipt of the shareholder redemption order; however, the fund may take up to 7 days to pay sale proceeds.

If you purchased shares through the fund’s transfer agent, you may sell them as explained below. The fund typically expects to pay sale proceeds by wire, ACH, or mailing a check, to redeeming shareholders within 1 business day following receipt of a shareholder redemption order; however, the fund may take up to 7 days to pay sale proceeds.

It costs the fund money to maintain shareholder accounts. Therefore, the fund reserves the right to repurchase all shares in any account that has a net asset value of less than $500. If the fund elects to do this with your account, it will notify you that you can increase the amount invested to $500 or more

within 60 days. The fund will not repurchase shares in accounts that fall below $500 solely because of a decrease in the fund’s net asset value.

Typically, redemptions of fund shares will be made by the fund wiring cash payments or deposits into your account. The fund typically expects to meet redemption requests by using holdings of cash or cash equivalents and/or proceeds from the sale of portfolio holdings. On a less regular basis, the fund may also draw on a bank line of credit to meet redemption requests. Although not routinely used by the fund, the fund reserves the right to pay proceeds “in kind” (i.e., payment in securities rather than cash) if the investment you are redeeming is large enough to affect the fund’s operations or in particularly stressed market conditions. In these cases, you might incur transaction costs converting the securities to cash. The securities included in a redemption in kind may include illiquid securities that may not be immediately saleable.

Transfer agent

If you wish to invest in the fund or another one of the Family Funds (“Family Funds” include PACE^® Select funds, series of The UBS Funds and other funds for which UBS AM (US) serves as principal underwriter) through the fund’s transfer agent, BNY Mellon Investment Servicing (US) Inc. (“BNY Mellon”), you can obtain an application by calling 1‑800‑647 1568. You must complete and sign the application and mail it, along with a check, to the transfer agent.

You may also sell your shares by writing to the fund’s transfer agent. Your letter must include:

 

 

 

 

Applications to purchase shares (along with a check), and letters requesting redemptions of shares through the transfer agent, should be mailed to:

BNY Mellon Investment Servicing (US) Inc.

UBS Asset Management

P.O. Box 9786

Providence, RI 02940

You do not have to complete an application when you make additional investments in the same fund.

Different procedures may apply to investments through the transfer agent by UBS AM (US) and UBS AM employees or members of (and nominees to) the board of directors/trustees (and former board members who retired from such boards after December 1, 2005) of any investment company for which UBS AM (US) or any of its affiliates serves as principal underwriter.

Unless you specifically elect otherwise, you will receive telephone privileges when you open your account, allowing you to obtain your account information, and conduct a number of transactions by phone, including: buy, sell, or exchange shares of the fund; use electronic funds transfer or wire to buy or sell shares of the fund; change your address; and add or change account services by calling 1‑800‑647 1568.

As long as we follow reasonable security procedures and act on instructions we reasonably believe are genuine, we will not be responsible for any losses that may occur from unauthorized requests. We will request account information and also may record calls to help safeguard your account, keep your account information confidential and verify the accuracy of your confirmation statements immediately after you receive them.

Contact us immediately if you believe someone has obtained unauthorized access to your account. Certain methods of contacting us (such as by phone) may be unavailable or delayed during periods of unusual market activity. If you have telephone privileges on your account and want to discontinue them, please contact us for instructions. You may reinstate these privileges at any time in writing.

Note that telephone privileges may not be available to all Family Funds. The fund may modify, suspend or terminate telephone privileges at any time. For more information, you should contact your investment professional or call 1‑800‑647 1568.

Transfer of accounts limitations

If you hold your shares with a securities firm, please note that if you change securities firms, you may not be able to transfer your fund shares to an account at the new securities firm. Fund shares may only be transferred to an account held with a securities dealer or financial intermediary that has entered into an agreement with the fund’s principal underwriter. If you cannot transfer your shares to another firm, you may choose to hold the shares directly in your own name with the fund’s transfer agent, BNY Mellon. Please contact your financial intermediary, for information on how to transfer your shares to the fund’s transfer agent. If you transfer your shares to the fund’s transfer agent, the fund’s principal underwriter may be named as

the dealer of record, and you will receive ongoing account statements from BNY Mellon.

Should you have any questions regarding the portability of your fund shares, please contact your financial intermediary.

Additional information about your account

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 an account. If you do not provide the information requested, the fund may not be able to maintain your account. If the fund is unable to verify your identity (or that of another person(s) authorized to act on your behalf) within a reasonable time, the fund and UBS AM (US) reserve the right to close your account and/or take such other action they deem reasonable or required by law. If we decide to close your account for this reason, your fund shares will be redeemed at the net asset value per share next calculated after the account is closed, less any applicable fees. You may recognize a gain or loss on the redemption of your fund shares and you may incur a tax liability.

The fund may suspend redemption privileges or postpone the date of payment beyond the same or next business day (1) for any period (a) during which the New York Stock Exchange (“NYSE”) is closed other than customary weekend and holiday closings or (b) during which trading on the NYSE is restricted; (2) for any period during which an emergency exists as a result of which (a) disposal by the fund of securities owned by it is not reasonably practicable or (b) it is not reasonably practicable for the fund fairly to determine the value of its net assets; (3) for such other periods as the SEC may by order permit for the protection of security holders

of the fund; or (4) to the extent otherwise permitted by applicable laws and regulations.

Market timing

Frequent purchases and redemptions of fund shares could increase the fund’s transaction costs, such as market spreads and custodial fees, and may interfere with the efficient management of the fund’s portfolio, which could impact the fund’s performance. However, it is anticipated that the fund may generally be used by investors for short-term investments. These investors value the ability to add and withdraw their funds quickly, without restriction. UBS AM (US) anticipates that shareholders may purchase and sell fund shares frequently, but also believes that the fund is unlikely to be a target of abusive trading practices. For these reasons, the fund’s board has not adopted policies and procedures, or imposed redemption fees or other restrictions such as minimum holding periods, to discourage excessive or short-term trading of fund shares. However, because frequent trading by shareholders can disrupt management of the fund and raise its expenses, UBS AM reserves the right to reject any request for a purchase or exchange if deemed to be used as a tool for market-timing, and may bar a shareholder who trades excessively from making further purchases for an indefinite period.

Other longer-term funds that are managed by UBS AM have approved policies and procedures designed to discourage and prevent abusive trading practices. For more information about market timing policies and procedures for these funds, please see the funds’ prospectuses.

Pricing and valuation

The price at which you may buy or sell fund shares is based on net asset value per share. The fund generally calculates its net asset value on days that the NYSE is open. The fund calculates its net asset value separately for each class as of the close of regular

trading on the NYSE (generally, 4:00 p.m., Eastern time). The NYSE normally is not open, and the fund does not price its shares, on most national holidays and on Good Friday. To the extent that the fund’s assets are traded in other markets on days when the NYSE is not open, the value of the fund’s assets may be affected on those days. If trading on the NYSE is halted for the day before 4:00 p.m., Eastern time, the fund’s net asset value per share generally will still be calculated as of the close of regular trading on the NYSE. The time at which the fund calculates its net asset value and until which purchase, sale or exchange orders are accepted may be changed as permitted by the SEC.

Your price for buying or selling shares will be based on the net asset value that is next calculated after the fund receives your order in good form. If you place your order on a day the NYSE is not open, your price for buying, selling, or exchanging shares will be based on the net asset value that is calculated on the next day that the NYSE is open. If you place your order through a financial intermediary, your financial intermediary is responsible for making sure that your order is promptly sent to the fund.

The fund calculates its net asset value based on the current market value, where available, for its portfolio securities. The fund normally obtains market values for its securities and other instruments from independent pricing sources and broker-dealers.

Independent pricing sources may use reported last sale prices, official market closing prices, current market quotations or valuations from computerized evaluation systems that derive values based on comparable securities or instruments. An evaluation system incorporates parameters such as security quality, maturity and coupon, and/or research and evaluations by its staff, including review of broker-dealer market price quotations, if available, in

determining the valuation of the portfolio securities or instruments. If a market value is not readily available from an independent pricing source for a particular security or instrument, that security or instrument is valued at fair value as determined in good faith by or under the direction of the board.

The amortized cost method of valuation, which approximates market value, generally is used to value short-term debt instruments with 60 days or less remaining to maturity, unless the board determines that this does not represent fair value. Investments in open‑end investment companies are valued at the daily closing net asset value of the respective investment company. All investments quoted in foreign currencies will be valued daily in US dollars on the basis of the foreign currency exchange rates prevailing at the time such valuation is determined by the fund’s custodian and accounting agent. Foreign currency exchange rates are generally determined as of the close of the NYSE.

Securities and instruments traded in the over-the-counter (“OTC”) market and listed on The NASDAQ Stock Market, Inc. (“NASDAQ”) normally are valued at the NASDAQ Official Closing Price. Other OTC securities are normally valued at the last bid price on the valuation date available prior to valuation. Securities and instruments that are listed on US and foreign stock exchanges normally are valued at the market closing price, the last sale price on the day the securities are valued or, lacking any sales on such day, at the last available bid price.

The board has designated UBS AM as the valuation designee pursuant to Rule 2a-5 under the 1940 Act, as amended, and delegated to UBS AM the responsibility for making fair value determinations with respect to the fund’s portfolio holdings. UBS AM, as the valuation designee, is responsible for periodically assessing any material risks associated

with the determination of the fair value of a fund’s investments; establishing and applying fair value methodologies; testing the appropriateness of fair value methodologies; and overseeing and evaluating third-party pricing services. UBS AM has a valuation committee to assist with its designated responsibilities as valuation designee. The types of securities and other instruments for which such fair value pricing may be necessary include, but are not limited to: foreign securities and instruments under some circumstances, as discussed below; securities of an issuer that has entered into a restructuring; securities or instruments whose trading has been halted or suspended; fixed income securities that are in default and for which there is no current market value quotation; Section 4(a)(2) commercial paper; securities or instruments that are restricted as to transfer or resale; illiquid instruments; and instruments for which the prices or values available do not, in the judgment of UBS AM, represent current market value. The need to fair value the fund’s portfolio securities and other instruments may also result from low trading volume in foreign markets or thinly traded domestic securities or instruments, and when a security subject to a trading limit or collar on the exchange or market on which it is primarily traded reaches the “limit up” or “limit down” price and no trading has taken place at that price.

Various factors may be reviewed in order to make a good faith determination of a security’s or instrument’s fair value. These factors include, but are not limited to, fundamental analytical data relating to the investment; the nature and duration of restrictions on disposition of the securities or instruments; and the evaluation of forces which influence the market in which the securities or instruments are purchased and sold.

The fund expects to price certain of its portfolio holdings based on current market value, as discussed previously. Securities and assets for which market quotations are not readily available may be valued based upon appraisals received from a pricing service using a computerized evaluation system or formula method that takes into consideration market indices, matrices, yield curves and other specific adjustments. This may result in the securities or other instruments being valued at a price different from the price that would have been determined had the evaluation or formula method not been used. Securities and other instruments also may be valued based on appraisals derived from information concerning the security or instrument or similar securities or instruments received from recognized dealers in those holdings. If the fund concludes that a market quotation is not readily available for a portfolio security or instrument for any number of reasons, including the occurrence of a “significant event” (e.g., natural disaster or governmental action), after the close of trading in its principal domestic or foreign market but before the close of regular trading on the NYSE, the fund will use fair value methods to reflect those events. This policy is intended to assure that the fund’s net asset value fairly reflects the value of its portfolio holdings as of the time of pricing. The fund may use a systematic fair valuation model provided by an independent third party to value securities or instruments principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. The systematic fair valuation model may use calculations based on indices of domestic securities and other appropriate indicators, such as prices of relevant American Depositary Receipts and futures contracts. If a security or instrument is valued at a “fair value,” that value is likely to be different from the last quoted market price for the security or instrument. In cases where securities or instruments

are traded on more than one exchange, the securities or instruments are valued on the exchange designated as the primary market by UBS AM, the investment advisor of the fund.

Valuing securities and other instruments at fair value involves greater reliance on judgment than valuing securities and other instruments that have readily available market quotations. Fair value determinations can also involve reliance on quantitative models employed by a fair value pricing service. There can be no assurance that the fund could obtain the fair value assigned to a security or instrument if it were to sell the security or instrument at approximately the time at which the fund determines its net asset value per share. As a result, the fund’s sale or redemption of its shares at net asset value, at a time when a holding or holdings are valued at fair value, may have the effect of diluting or increasing the economic interest of existing shareholders.

The fund may invest in securities or instruments that trade primarily in foreign markets that trade on weekends or other days on which the fund does not calculate its net asset value. As a result, the fund’s net asset value may change on days when you will not be able to buy and sell your fund shares. Certain securities or instruments in which the fund may invest are traded in markets that close before 4:00 p.m., Eastern time. Normally, developments that occur between the close of the foreign markets and 4:00 p.m., Eastern time, will not be reflected in the fund’s net asset value. However, if the fund determines that such developments are so significant that they will materially affect the value of the fund’s securities or instruments, the fund may adjust the previous closing prices to reflect what the board believes to be the fair value of these securities or instruments as of 4:00 p.m., Eastern time.

Futures contracts are generally valued at the settlement price established each day on the exchange on which they are traded. Forward foreign currency contracts are valued daily using forward exchange rates quoted by independent pricing services. Swaps and other OTC derivatives are marked to market daily based upon values from third party vendors or quotations from market makers to the extent available. In the event that market quotations are not readily available or deemed unreliable, the swap is valued at fair value as determined in good faith by or under the direction of the board.

The fund’s portfolio holdings may also consist of shares of other investment companies in which the fund invests. The value of each such open‑end investment company will generally be its net asset value at the time the fund’s shares are priced. The value of closed‑end investment company securities and shares of ETFs will generally be market price. Pursuant to the fund’s use of the practical expedient within ASC Topic 820, investments in non‑registered investment companies are also valued at the daily net asset value. Each investment company generally values securities and other instruments in a manner as described in that investment company’s prospectus or similar document.

Management

Investment advisor

Portfolio managers

UBS AM’s investment professionals are organized into investment management teams, with a particular team dedicated to a specific asset class.

Robert Sabatino, David Walczak, David Rothweiler and Scott Dolan are the portfolio managers for the fund. As portfolio managers, Messrs. Sabatino, Walczak, Rothweiler and Dolan have primary responsibility for managing the fund’s day‑to‑day investment operations and reviewing the overall composition of the portfolio in an effort to ensure its compliance with its stated investment objective.

Mr. Sabatino is a Vice President of UBS Series Funds (since 2001) and a managing director (since 2010) (prior to which he was an executive director (from 2007 to 2010)), head of global liquidity portfolio management (since 2015), head of US taxable money markets (from 2009 to 2015), and portfolio manager of UBS AM—Liquidity Management team (since 2001).

Mr. Walczak is a Vice President of UBS Series Funds and an executive director (since 2016), head of US money markets (since 2015) and portfolio manager of UBS AM—Liquidity Management team (since 2007).

Mr. Rothweiler is an executive director (since 2018) and senior portfolio manager of US ultra short, short duration, and intermediate portfolios (since 2004) for UBS AM.

Mr. Dolan is head of US multi-sector fixed income and a managing director at UBS AM. Prior to joining UBS AM in 2008, Mr. Dolan was a managing director and head of securitized assets for Citigroup Alternative Investments. Prior to joining Citigroup, Mr. Dolan was a managing director and head of mortgages and structured assets for Bear Stearns Asset Management and a senior mortgage trader at the Clinton Group. Mr. Dolan also worked at Deutsche Asset Management as a managing director and co‑head of the Rates Group responsible for strategy, security selection and trading for MBS, ABS, agencies and treasuries. Mr. Dolan started his career at Scudder, Stevens and Clark, where he managed total return fixed income mutual funds and institutional portfolios.

The SAI provides additional information about the compensation of, and any other accounts managed by, and any fund shares held by, Messrs. Sabatino, Walczak, Rothweiler and Dolan.

Advisory and administration fees

Other information

To the extent authorized by law, the fund reserves the right to discontinue offering shares at any time, merge, reorganize itself or its classes of shares or cease operations and liquidate. The fund also reserves the right, without shareholder approval, to convert to a master-feeder structure in which the fund as a “feeder fund” invests all of its assets in a “master fund,” which would have the same investment objective.

Dividends and taxes

Dividends

The fund declares dividends daily and pays them monthly. Dividends accrued during a given month

are paid on the first business day of the next month or upon the sale of all the fund shares in a shareholder’s account. The fund may distribute all or a portion of its capital gains (if any) to the extent required to ensure that the fund maintains its federal tax law status as a regulated investment company.

Classes with higher expenses are expected to have lower dividends. For example, Class A shares (offered in a separate prospectus with Class P shares) are expected to have the lowest dividends of the fund’s shares, while Class I shares are expected to have the highest.

You will receive dividends in additional shares of the same class unless you elect to receive them in cash. If you prefer to receive dividends in cash, contact your financial intermediary (or the fund’s transfer agent if you invested in the fund through its transfer agent). Distributions declared in October, November or December, but not paid until January of the following year, are taxed as though they were paid on December 31 of the year in which they were declared.

Taxes

The dividends that you receive from the fund generally are subject to federal income tax regardless of whether you receive them in additional fund shares or in cash. If you hold fund shares through a tax‑exempt account or plan, such as an IRA or 401(k) plan, dividends on your shares generally will not be subject to tax before you receive distributions from the account or plan.

When you sell fund shares, you generally will be subject to federal income tax on any gain you realize. The gain will be taxed at the long-term capital gains rate (discussed below) if you hold your shares for more than one year. Otherwise the gain is short-term capital gain which is generally taxed as ordinary income.

Fund dividends derived from investment income (other than qualifying dividends, discussed below) are generally taxable to you as ordinary income. Fund distributions of gains are treated as long-term capital gains to the extent the fund derives long-term capital gains and are treated as ordinary income to the extent the fund derives short-term capital gains. The fund will send you a tax report annually summarizing the amount of and the tax aspects of your distributions.

The maximum individual rate applicable to qualifying dividends on certain corporate stock and long-term capital gains is generally either 15% or 20%, depending on whether the individual’s income exceeds certain threshold amounts. These rate reductions do not apply to corporate taxpayers or to non‑US shareholders. A shareholder will also have to satisfy a more than 60-day holding period with respect to any distributions of qualifying dividends in order to obtain the benefit of the lower tax rate. Distributions of earnings from non‑qualifying dividends, interest income, other types of ordinary income and short-term capital gains will be taxed at the ordinary income tax rate applicable to the taxpayer.

An additional 3.8% Medicare tax is imposed on certain net investment income (including ordinary dividends and capital gain distributions received from the fund and net gains from redemptions or other taxable dispositions of fund shares) of US individuals, estates and trusts to the extent that such person’s “modified adjusted gross income” (in the case of an individual) or “adjusted gross income” (in the case of an estate or trust) exceeds certain threshold amounts.

The fund is required to report to you and the IRS annually on Form 1099‑B not only the gross proceeds of fund shares you sell or redeem but also their cost basis for such shares. Cost basis will be calculated using the fund’s default method of average

cost, unless you instruct the fund to use a different available calculation method. If you hold your shares through a financial intermediary you should contact such financial intermediary with respect to reporting of cost basis and available elections for your account.

If you have not provided complete and correct taxpayer identification to us or if you are subject to “backup withholding,” by law we must withhold 24% of your distributions and redemption proceeds to pay US federal income taxes.

Taxable distributions to non-US shareholders are generally expected to be subject to a 30% withholding tax. Distributions to non-US shareholders of short-term capital gains and interest income are expected to be subject to withholding tax because certain detailed information necessary for a possible exemption is not expected to be available.

The above is a general and abbreviated discussion of certain tax considerations, and each investor is advised to consult with his or her own tax advisor. There is additional information on taxes in the fund’s SAI.

Disclosure of portfolio holdings

The fund will generally post on UBS AM’s website at www.ubs.com/usshortduration, its full portfolio holdings and the percentage that each of these

holdings represents of the fund’s total assets, as of the most recent calendar-month end, on or about 10 days after the end of the calendar month.

The fund’s complete schedule of portfolio holdings for the first and third quarters of its fiscal year will be publicly available on the SEC’s website as part of periodic filings on Form N-PORT for such periods. The fund’s complete schedule of portfolio holdings for the second and fourth quarters of each fiscal year is included in its semiannual and annual reports to shareholders and is filed with the SEC on Form N‑CSR. The fund’s Forms N-PORT for the last month of the applicable fiscal quarter and Forms N‑CSR are available on the SEC’s website at http://www.sec.gov. Additionally, you may obtain copies of Forms N-PORT and annual and semiannual reports to shareholders from the fund upon request by calling 1‑800‑647 1568. The annual and semiannual reports for the fund will also be posted on the fund’s website at www.ubs.com/usshortduration. Please consult the fund’s SAI for a description of the policies and procedures that govern disclosure of the fund’s portfolio holdings.

The following financial highlights table is intended to help you understand the fund’s financial performance for the fiscal periods indicated. Certain information reflects financial results for a single fund share. In the table, “total investment return” represents the rate that an investor would have earned (or lost) on an investment in the fund (assuming reinvestment of all dividends and distributions).

The information in the financial highlights has been derived from the financial statements audited by Ernst & Young LLP, an independent registered public accounting firm, whose report, along with the fund’s financial statements, is included in the fund’s annual report to shareholders. The annual report may be obtained without charge by calling 1‑800‑647 1568.

 

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Prospectus  |  August 28, 2023