Prospectus | August 28, 2026

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

 

 

The fund only sells its shares through the sweep program available to certain clients of UBS Financial Services Inc. though “eligible benefit plans,” which include: qualified plans with a pooled structure and 403(b) plans, including, in the case of both such plans, accounts opened by participants therein. The fund is only available as a sweep fund for the automatic sweep of free credit balances in your eligible securities account. The fund has no minimum to add to an account through the automatic sweep arrangement. Your fund shares will be sold automatically to settle any outstanding securities purchases or debits to your securities account. Shares may be purchased and redeemed on any business day on which the Boston offices of the fund’s custodian and the New York City offices of UBS Financial Services Inc. and its affiliated bank are all open for business.

Additional information about the investment objective

The fund’s investment objective may not be changed without shareholder approval.

Additional information about investment strategies

The fund’s board has determined that the fund will operate as a “government money market fund” pursuant to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”), (“Rule 2a-7”). Therefore, the fund has adopted a

policy to invest 99.5% or more of its total assets in cash, government securities, and/or repurchase agreements that are collateralized fully (i.e., collateralized with cash and/or government securities). As a “government money market fund,” the fund (1) is permitted to use the amortized cost method of valuation to seek to maintain a $1.00 share price, and (2) is not subject to a liquidity fee on fund redemptions which might apply to other types of funds under certain circumstances. (In conformance with Rule 2a-7, the fund’s board has reserved its ability to change this policy, but such change would only become effective after shareholders were provided with specific advance notice of a change in the fund’s policy and have the opportunity to redeem their shares in accordance with Rule 2a-7 before the policy change became effective.)

Like all money market funds, the fund is subject to maturity, quality, diversification and liquidity

requirements under Rule 2a-7. The fund’s investment strategies are designed to comply with these requirements. The fund may invest in high quality, short-term, US dollar-denominated money market instruments paying a fixed, variable or floating interest rate.

UBS AM may use a number of professional money management techniques to respond to changing economic and money market conditions and to shifts in fiscal and monetary policy. These techniques include varying the fund’s composition and weighted average maturity based upon UBS AM’s assessment of the relative values of various money market instruments and future interest rate patterns. UBS AM also may buy or sell money market instruments to take advantage of yield differences.

Although not a principal strategy of the fund, the fund may invest to a limited extent in shares of similar money market funds. The fund’s investments in other money market funds that comply with the definition of a “government money market fund” under Rule 2a-7 will be treated as investments in the underlying securities held by such money market funds for the purposes of the fund’s policy to invest 99.5% or more of its total assets in cash, government securities, and/or repurchase agreements that are collateralized fully (i.e., collateralized by cash and/or government securities).

Additional information about principal risks

The main risks of investing 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 Statement of Additional Information (“SAI”). Information on how you can obtain the SAI can be found on the back cover of this prospectus.

Interest rate risk. The value of the fund’s investments 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 will fall. Also, the fund’s yield will tend to lag behind changes in prevailing short-term interest rates. This means that the fund’s income will tend to rise more slowly than increases in short-term interest rates. Similarly, when short-term interest rates are falling, the fund’s income generally will tend to fall more slowly. Securities with longer maturities generally are subject to greater fluctuations in value. Changes in interest rates will likely affect the value of higher-quality securities more than lower-quality securities. A substantial increase in interest rates may have an adverse impact on the liquidity and valuation of a security, especially those with longer maturities. Interest rate changes can be sudden and unpredictable and are influenced by a number of factors, including government policy, monetary policy, inflation expectations, perceptions of risk, and supply and demand for fixed-income securities. There can

be no guarantee that any particular government or central bank policy will be continued (or discontinued) or changed, nor that any such policy will have the desired effect on interest rates.

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. Securities that do not carry the backing of the full faith and credit of the US government are subject to more credit risk than securities

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 and environmental disasters, recessions, rapid inflation, cyber-attacks or incidents, the imposition of international sanctions, trade disputes and changes in trade regulation (including tariffs or other restrictions on trade), elevated levels of government debt, internal unrest and discord, or 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.

Liquidity risk. The fund’s investments may become less liquid due to market developments or adverse

investor perception. When there is no willing buyer and investments cannot be readily sold at the desired time or price, the fund may have to accept a lower price or may not be able to sell an instrument at all. The inability to sell an instrument could adversely affect the fund’s ability to maintain a $1.00 share price or prevent the fund from being able to take advantage of other investment opportunities. This risk may increase during an unusually high volume of redemption requests by even a few large investors or unusual market conditions, when prices of securities are negatively impacted by rapid or unexpected changes in interest rates, or as a result of government intervention, political, social, health, economic or market developments.

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 advisor may be incorrect in its assessment of a particular security or assessment of market, interest rate or other trends, which can result in losses to the fund. Consequently, the fund may underperform in comparison to other funds with similar objectives and investment strategies.

Additional (non-principal) risks

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.

Temporary and defensive positioning. During adverse market conditions or when the advisor believes there is an insufficient supply of appropriate money market securities in which to invest, the fund may temporarily hold uninvested cash in lieu of such investments. During periods when such temporary or defensive positions are held, the fund may not be able to fully pursue its investment objective. Such positions may also subject the fund to additional costs and risks, such as increased exposure to cash held at a custodian bank.

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.

Geopolitical tensions may increase the scale and sophistication of deliberate attacks, particularly those from nation-states or from entities with nation-state backing. While the fund’s advisor has established business continuity plans and risk management systems seeking to address system breaches or failures, there are inherent limitations in such plans and systems. The fund cannot control the cybersecurity plans and systems of its service providers, counterparties, and other third parties whose activities affect the fund.

Buying shares

Automatic sweep programs. UBS Financial Services Inc. administers cash sweep programs under which free cash balances in certain client securities accounts are automatically “swept” or invested in shares in the fund. The terms and eligibility requirements for the sweep programs are described in the UBS Account Agreements.

Background information. Your purchase of fund shares will be priced at the next determination of net asset value on any business day after federal funds become available to the fund. Federal funds are funds deposited by a commercial bank in an account at a Federal Reserve bank that can be transferred to a similar account of another bank in one day and thus can be made immediately available to the fund. A business day is any day that the Boston offices of the fund’s custodian and the New York City offices of UBS Financial Services Inc. and its affiliated bank are all open for business. One or more of these institutions will be closed on the observance of the following holidays: New Year’s Day, Martin Luther King, Jr. Day, President’s Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Columbus Day, Veteran’s Day, Thanksgiving Day and Christmas Day.

The fund, UBS AM and UBS Asset Management (US) Inc., the fund’s distributor (“UBS AM (US)”), have the right to reject a purchase order and to suspend the offering of fund shares for a period of time or permanently.

The fund pays no sales commission, sales load or distribution fees to its principal underwriter, UBS AM (US), and its affiliates, or any other person, in connection with the sale of fund shares. Neither UBS AM (US) nor any affiliate exercises any discretion with respect to the timing or frequency of the automatic investment of free cash balances.

Minimum investments

The fund has no minimum for initial investments or to add to an account, but reserves the right to establish minimum investment requirements at any time.

 

 

 

 

 

 

Although the amount that you may contribute to an eligible benefit plan in any one year is subject to certain limitations, you may invest and reinvest assets already held in an eligible benefit plan in the fund without regard to these limitations.

Selling shares

Shares of the fund are sold automatically in the order described in the UBS Account Agreements to settle any outstanding securities purchases or other debits to your UBS Financial Services Inc. securities account.

Additional information about your account

Investment programs buying or holding shares for their client accounts may charge clients for cash management and other services provided in connection with their accounts.

You should consider the terms of your investment program before purchasing shares.

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.

Upon receipt of a proper redemption request submitted in a timely manner and otherwise in accordance with the redemption procedures set forth in this prospectus, the fund will redeem the requested shares and make a payment. The fund may postpone and/or suspend redemption and payment beyond one business day (but within seven calendar days) for any period during which there is a non-routine closure of the Fedwire or applicable Federal Reserve Banks. In addition, the fund may also postpone or suspend redemption and payment as follows: (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 net asset value of shares of the fund; (3) for any period during which the US Securities and Exchange Commission (“SEC”) has, by rule or regulation, deemed that (a) trading shall be restricted or (b) an emergency exists; (4) for any period that the SEC may by order permit for your protection; or (5) for any period during which the fund, as part of a necessary liquidation of the fund, has properly postponed and/or suspended redemption of shares and payment in accordance with federal securities laws.

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, money market funds are generally used by investors for short-term investments, often in place of bank checking or savings accounts or for cash management purposes. Investors value the ability to add and withdraw their funds quickly, without restriction. UBS AM (US) anticipates that shareholders will purchase and sell fund shares frequently because the fund is designed to offer investors a liquid cash option. UBS AM (US) also believes that money market funds, such as the fund, are not targets 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.

Other UBS funds that are managed by UBS AM that are not money market funds 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 of fund shares is based on net asset value. The net asset value per share is equal to the value of all the assets of the fund, minus the liabilities of the fund, divided by the number of shares outstanding. In determining net asset value, the fund values its securities at their amortized cost, unless the fund’s board (or UBS AM as valuation designee) determines that this does not represent fair value. The amortized cost method uses a constant amortization to maturity of the difference between the cost of the instrument to the fund and the amount due at maturity. The fund’s net asset value per share is expected to be $1.00, although this value is not guaranteed.

The fund typically calculates net asset value per share once each business day as of 12:00 noon, Eastern time. Your price for buying or selling shares will be the net asset value that is next calculated after the fund receives your order in good form.

The fund’s board designated UBS AM as the valuation designee pursuant to Rule 2a-5 under the 1940 Act and delegated to UBS AM the responsibility for making fair value determinations with respect to the fund’s portfolio securities. UBS AM, as the valuation designee, is responsible for periodically assessing any material risks associated with the determination of the fair value of the 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: securities of an issuer that has entered into a restructuring; fixed-income securities that have

gone into 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 may also result from low trading volume in foreign markets or thinly traded securities or instruments. 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.

Although not a principal strategy of the fund, the fund’s portfolio investments 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. 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

Advisory and administration fees

Under the agreement with the fund, UBS AM manages the investment operations of the fund and also administers the fund’s business affairs.

UBS AM is entitled to be reimbursed by the fund for its direct advisory and administrative costs and expenses, excluding any profit or overhead, incurred in providing services to the fund. UBS AM’s costs include the following: (i) paying the salaries and expenses of the fund’s officers and other personnel engaged in administering the fund’s business; (ii) monitoring financial and shareholder accounting services provided by the fund’s custodian/sub-administrator and transfer agent, respectively; (iii) responding to shareholder inquiries and disseminating information to shareholders; (iv) monitoring compliance with the fund’s registration statement and other operating documents, with federal and state securities laws and rules thereunder and with the Internal Revenue Code; (v) preparing semiannual and annual reports to shareholders; (vi) preparing filings required by the SEC; (vii) assisting in the preparation of federal, state and local tax returns; (viii) assisting with the payment of notice filing fees under state securities laws; (ix) organizing annual and special meetings of the fund’s shareholders; and (x) paying any other costs and expenses UBS AM incurs in managing the portfolio of the fund. UBS AM periodically will review fund expenses in an effort to confirm that only direct costs and expenses are paid to UBS AM by the fund. The fund will incur other expenses in its operations.

Other information

To the extent authorized by law, the fund reserves the right to discontinue offering shares at any time, merge, reorganize itself or cease operations and liquidate.

Dividends and taxes

Dividends

The fund declares dividends daily and pays them monthly. 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. The fund will also distribute all or a portion of its capital gains to the extent necessary to maintain its share price at $1.00.

You will receive dividends in additional shares of the fund. Shares earn dividends on the day they are purchased but not on the day they are sold.

While the fund declares dividends daily and pays them monthly, the amounts are rounded to the nearest $0.01 on a daily basis with respect to each investor’s fund account. As a result, investors whose fund account balances earn daily dividends that total less than one half a cent on any given day will not accrue any dividends on that day.

The fund notifies its shareholders following the end of each calendar year of the amount of all dividends paid that year.

Taxes

Eligible benefit plan participants ordinarily do not pay taxes on dividends their plans receive on fund shares until they withdraw the proceeds from the plan. Generally, withdrawals from an eligible benefit plan will be taxable as ordinary income. Withdrawals will be subject to an additional tax equal to 10% of the amount distributed unless the withdrawals are used to pay certain higher education expenses, certain acquisition costs of first-time home buyers, or in certain situations, are made after the participant:

 

 

You should consult your tax adviser concerning the timing and tax consequences of withdrawals from your eligible benefit plan.

Although dividends are generally treated as taxable to you in the year they are paid, dividends declared in October, November or December but paid in January are taxable as if they were paid in December.

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 may be required to withhold a 24% federal tax on all dividends payable to you

 

 

Taxable distributions to non-residents will generally be subject to a 30% withholding tax (or lower applicable treaty rate).

The fund is required to withhold US tax (at a 30% rate) on payments of taxable dividends made to certain non-US entities that fail to comply (or be deemed compliant) with extensive reporting and withholding requirements designed to inform the US Department of the Treasury of US-owned foreign investment accounts. Shareholders may be requested to provide additional information to the fund to enable the fund to determine whether withholding is required.

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 and other information

The fund’s complete schedule of portfolio holdings for the second and fourth quarters of each fiscal year is filed with the SEC on Form N‑CSR. The fund’s Forms N-CSR are available on the SEC’s website at

http://www.sec.gov. Additionally, you may obtain copies of semiannual and annual reports to shareholders from the fund upon request by calling 1‑800‑647 1568. The semi‑annual and annual reports for the fund will be posted on the fund’s website at https://www.ubs.com/usmoneymarketfunds.

The fund will disclose on UBS AM’s website, within five business days after the end of each month, a complete schedule of portfolio holdings and information regarding the weighted average maturity and weighted average life of the fund. This information will be posted on the UBS website at the following internet address: https://www.ubs.com/usmoneymarketfunds. In addition, the fund will file with the SEC on Form N-MFP, within five business days after the end of each month, more detailed portfolio holdings information. The fund’s Forms N-MFP will be available on the SEC’s website; UBS AM’s website will also contain a link to these filings. The UBS AM website will also disclose the following information for the fund as of the end of each business day for the previous six months: (1) the percentage of the fund’s total assets invested in daily and weekly liquid assets; (2) the fund’s daily net inflows and outflows; and (3) the fund’s current market-based net asset value per share to four decimal places, which is calculated using current market quotations (or an appropriate substitute that reflects current market conditions). (For purposes of transactions in shares of the fund, the price for shares will be the net asset value per share, calculated using the amortized cost method to two decimal places as further described in this prospectus and the related SAI.) Investors also may find additional information about the fund at the above referenced UBS website internet address.

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 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 appears in the fund’s Form N-CSR. You may obtain copies of the fund’s Form N-CSR without charge by calling toll free 1-800-647 1568.

© UBS 2026. All rights reserved.

Prospectus | August 28, 2026

Prospectus | August 28, 2026

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

The fund is not a complete or balanced investment program.

 

 

Investments in the fund are intended to be limited to corporate cash management accounts, financial institutions and certain independently advised accounts. The fund is offered as a sweep fund for the automatic investment of free credit balances in your securities account. The fund has no minimum to add to an account. Your fund shares will be sold automatically to settle any outstanding securities purchases or debits to your securities account. Shares of the fund will automatically be purchased or redeemed on any business day on which the Boston offices of the fund’s custodian and the New York City offices of UBS Financial Services Inc. and its bank are all open for business.

Additional information about the investment objective

The fund’s investment objective may not be changed without shareholder approval.

Additional information about investment strategies

The fund’s board has determined that the fund will operate as a “government money market fund” pursuant to Rule 2a-7 under the Investment Company Act of 1940, as amended (the “1940 Act”), (“Rule 2a-7”). Therefore, the fund has adopted a policy to invest 99.5% or more of its total assets in cash, government securities, and/or repurchase agreements that are collateralized fully (i.e., collateralized with cash and/or government securities). As a “government money market fund,” the fund (1) is permitted to use the amortized cost method of valuation to seek to maintain a $1.00 share price, and (2) is not subject to a liquidity fee on fund redemptions which might apply to other types of funds under certain circumstances. (In conformance with Rule 2a‑7, the fund’s board has reserved its ability to change this policy, but such change would only become effective after shareholders were provided with specific advance notice of a change in the fund’s policy and have the opportunity to redeem their shares in accordance with Rule 2a-7 before the policy change became effective.)

changed by the fund’s board without shareholder approval. However, the fund has also adopted a policy to provide its shareholders with at least 60 days’ prior written notice of any change to the 80% investment policy.

Like all money market funds, the fund is subject to maturity, quality, diversification and liquidity requirements under Rule 2a-7. The fund’s investment strategies are designed to comply with these requirements. The fund may invest in high quality, short-term, US dollar-denominated money market instruments paying a fixed, variable or floating interest rate.

UBS AM may use a number of professional money management techniques to respond to changing economic and money market conditions and to shifts in fiscal and monetary policy. These techniques include varying the fund’s composition and weighted average maturity based upon UBS AM’s assessment of the relative values of various money market instruments and future interest rate patterns. UBS AM also may buy or sell money market instruments to take advantage of yield differences.

The master fund in which the fund invests may maintain a rating from one or more rating agencies that provide ratings on money market funds. There can be no assurance that the master fund will maintain any particular rating or maintain it with a particular rating agency. To maintain a rating, UBS AM may manage the master fund more conservatively or differently than if it were not rated.

Additional information about principal risks

The main risks of investing 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 Statement of

Additional Information (“SAI”). Information on how you can obtain the SAI can be found on the back cover of this prospectus.

Interest rate risk. The value of the fund’s investments 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 will fall. Also, the fund’s yield will tend to lag behind changes in prevailing short-term interest rates. This means that the fund’s income will tend to rise more slowly than increases in short-term interest rates. Similarly, when short-term interest rates are falling, the fund’s income generally will tend to fall more slowly. Securities with longer maturities generally are subject to greater fluctuations in value. Changes in interest rates will likely affect the value of higher-quality securities more than lower-quality securities. A substantial increase in interest rates may have an adverse impact on the liquidity and valuation of a security, especially those with longer maturities. Interest rate changes can be sudden and unpredictable and are influenced by a number of factors, including government policy,

monetary policy, inflation expectations, perceptions of risk, and supply and demand for fixed-income securities. There can be no guarantee that any particular government or central bank policy will be continued (or discontinued) or changed, nor that any such policy will have the desired effect on interest rates.

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. Securities that do not carry the backing of the full faith and credit of the

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 and environmental disasters, recessions, rapid inflation, cyber-attacks or incidents, the imposition of international sanctions, trade disputes and changes in trade regulation (including tariffs or other restrictions on trade), elevated levels of government debt, internal unrest and discord, or 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.

Liquidity risk. The fund’s investments may become less liquid due to market developments or adverse investor perception. When there is no willing buyer and investments cannot be readily sold at the desired time or price, the fund may have to accept a lower price or may not be able to sell an instrument at all. The inability to sell an instrument could adversely affect the fund’s ability to maintain a $1.00 share price or prevent the fund from being able to take advantage of other investment opportunities. This risk may increase during an unusually high volume of redemption requests by even a few large investors or unusual market conditions, when prices of securities are negatively impacted by rapid or unexpected changes in interest rates, or as a result of government intervention, political, social, health, economic or market developments.

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 advisor may be incorrect in its assessment of a particular security or assessment of market, interest rate or other trends, which can result in losses to the fund. Consequently, the fund may underperform in comparison to other funds with similar objectives and investment strategies.

US withholding tax risk. The fund generally seeks to invest in securities the income from which is considered “qualified interest income” under relevant tax law and guidance. Thus, the fund generally expects its distributions to be exempt from US withholding tax when paid to non-US investors. However, there can be no assurance that all of the fund’s distributions will be exempt from US withholding tax. Non-US investors should see the sections entitled “Dividends and taxes” and sub-section “Taxes” for more information.

Additional (non-principal) risks

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.

Temporary and defensive positioning. During adverse market conditions or when the advisor believes there is an insufficient supply of appropriate money market securities in which to invest, the fund may temporarily hold uninvested cash in lieu of such investments. During periods when such temporary or defensive positions are held, the fund may not be able to fully pursue its investment objective. Such positions may also subject the fund to additional costs and risks, such as increased exposure to cash held at a custodian bank.

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

Buying Shares

Automatic sweep programs. The fund is offered as a sweep fund for the automatic investment of free credit balances in certain client securities accounts at UBS Financial Services Inc. The fund has no minimum to add to an account through the automatic sweep arrangement. Your fund shares will be sold automatically to settle any outstanding securities purchases or debits to your securities account. Shares may be purchased and redeemed on any business day on which the Boston offices of the fund’s custodian and the New York City offices of UBS Financial Services Inc. and its affiliated bank are all open for business.

and its bank are all open for business. One or more of these institutions will be closed on the observance of the following holidays: New Year’s Day, Martin Luther King, Jr. Day, Presidents’ Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Columbus Day, Veterans Day, Thanksgiving Day and Christmas Day.

The fund has adopted a shareholder services (non-rule 12b-1) plan under which the fund pays fees for services provided to its shareholders at the annual rate of 0.25% of its average daily net assets.

The fund, UBS AM and UBS Financial Services Inc. have the right to reject a purchase order and to suspend the offering of fund shares for a period of time or permanently.

All free cash balances in eligible securities accounts of $1.00 or more (or for IRAs, of $0.01 or more), including proceeds from the securities you have sold, are automatically invested in your sweep option on a daily basis for settlement the same day.

(Federal funds normally are available to be swept into your sweep option on the next business day. Federal funds availability can sometimes take longer for cash balances arising from the sale of securities in your brokerage account.)

Fund shares will be purchased only after all debits and charges to your brokerage account are satisfied. See “Selling shares automatically” below.

Minimum investment. The fund has no minimum to add to an account, but reserves the right to establish minimum investment requirements at any time.

UBS AM has entered into an agreement with its

affiliate, UBS Financial Services Inc., under which UBS AM (or its affiliate UBS Asset Management (US) Inc., the fund’s distributor (“UBS AM (US)”)) pays UBS Financial Services Inc. additional compensation in connection with the sale of fund shares and the provision of administrative and shareholder services.

The aggregate amount of these payments may be substantial and may represent a significant portion of the advisory and administrative fees charged by UBS AM. These payments do not increase the expenses of a fund, but are made by UBS AM (or its affiliate UBS AM (US)) out of its own legitimate profits or other resources. The payments may include amounts that are sometimes referred to as “revenue sharing” payments.

Typically, redemptions of fund shares will be made by the fund wiring a cash payment or deposit 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 or maturity of portfolio holdings. 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.

The list of eligible participants may change at the discretion of UBS Financial Services Inc.

Additional information about your account. It costs the fund money to maintain shareholder

UBS Financial Services Inc. has the right to terminate your securities account for any reason. In that case, UBS Financial Services Inc. will sell all of the fund shares held in the account and will send you the proceeds within three business days.

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.

Upon receipt of a proper redemption request submitted in a timely manner and otherwise in accordance

with the redemption procedures set forth in this prospectus, the fund will redeem the requested shares and make a payment. The fund may postpone and/or suspend redemption and payment beyond one business day (but within seven calendar days) for any period during which there is a non-routine closure of the Fedwire or applicable Federal Reserve Banks. In addition, the fund may also postpone or suspend redemption and payment as follows: (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 net asset value of shares of the fund; (3) for any period during which the US Securities and Exchange Commission (“SEC”) has, by rule or regulation, deemed that (a) trading shall be restricted or (b) an emergency exists; (4) for any period that the SEC may by order permit for your protection; or (5) for any period during which the fund, as part of a necessary liquidation of the fund, has properly postponed and/or suspended redemption of shares and payment in accordance with federal securities laws.

Please note that additional fees may apply for optional RMA/Business Services Account BSA program services. Please refer to the UBS Account Agreements or speak with your Financial Advisor for information regarding program fees.

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, money market funds are generally used by investors for short-term investments, often in place of bank checking or savings

accounts or for cash management purposes. Investors value the ability to add and withdraw their funds quickly, without restriction. UBS AM (US) anticipates that shareholders will purchase and sell fund shares frequently because the fund is designed to offer investors a liquid cash option.

UBS AM (US) also believes that money market funds, such as the fund offered in this prospectus, are not targets 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.

Other UBS funds that are managed by UBS AM that are not money market funds 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 of fund shares is based on net asset value. The net asset value per share is equal to the value of all the assets of the fund, minus the liabilities of the fund divided by the number of shares outstanding. In determining net asset value, the master fund values its securities at their amortized cost (unless the fund’s board (or UBS AM as valuation designee) determines that this does not represent fair value), and the fund buys the master fund’s interests at the master fund’s net asset value. The amortized cost method uses a constant amortization to maturity of the difference between the cost of the instrument to the fund and the amount due at maturity. The fund’s net asset value per share is expected to be $1.00, although this value is not guaranteed.

The fund typically calculates net asset value per share once each business day as of 12:00 noon,

Eastern time. Your price for buying or selling shares will be the net asset value that is next calculated after the fund receives your order in good form.

The fund’s board designated UBS AM as the valuation designee pursuant to Rule 2a-5 under the 1940 Act and delegated to UBS AM the responsibility for making fair value determinations with respect to the fund’s portfolio securities. UBS AM, as the valuation designee, is responsible for periodically assessing any material risks associated with the determination of the fair value of the 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: securities of an issuer that has entered into a restructuring; fixed-income securities that have gone into 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 may also result from low trading volume in foreign markets or thinly traded securities or instruments. 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’s portfolio holding consists of an interest in the master fund in which the fund invests. The

value of such portfolio holding reflects the fund’s proportionate interest in the net assets of the master fund. The master fund generally values securities and other instruments in a manner as described in the master fund’s prospectus or similar document.

Management

Investment advisor

UBS Asset Management (Americas) LLC (“UBS AM”) acts as the investment advisor and administrator for Government Master Fund which is the master fund in which the fund invests its assets. UBS AM also acts as the administrator for the fund. As investment advisor, UBS AM makes the master fund’s investment decisions. It buys and sells securities for the master fund and conducts the research that leads to the purchase and sale decisions.

Advisory and administration fees

UBS AM’s contract fee for the advisory and administrative services it provides to the Master Fund is based on the following fee schedule:

 

UBS AM’s contract fee for the administrative services it provides to the fund is 0.10% of the fund’s average daily net assets.

UBS AM may voluntarily waive fees from time to time. For example, UBS AM may voluntarily undertake to waive fees in the event that fund yields drop below a certain level. Once started, there is no guarantee that UBS AM would continue to voluntarily waive a portion of its fees. Waivers may impact a fund’s performance.

Master-feeder structure

The fund is a “feeder fund” that invests all of its assets in a “master fund”—Government Master Fund. The fund and the master fund have the same investment objective.

The master fund may accept investments from other feeder funds. Each feeder fund bears the master fund’s expenses in proportion to its investment in the master fund. Each feeder fund can set its own transaction minimums, feeder fund-specific expenses and other conditions. This arrangement allows each feeder fund’s trustees to withdraw the feeder fund’s assets from the master fund if they believe doing so is in the shareholders’ best interests. If the trustees withdraw the feeder fund’s assets, they would then consider whether the feeder fund should hire its own investment advisor, invest in a different master fund or take other action.

Other information

To the extent authorized by law, the fund reserves the right to discontinue offering shares at any time merge, reorganize itself or cease operations and liquidate.

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. The fund will also distribute all or a portion of its capital gains to the extent necessary to maintain its share price at $1.00.

Shares of the fund earn dividends on the day they are purchased but do not earn dividends on the day they are sold.

You will receive dividends in additional shares unless you elect to receive them in cash. If you prefer to receive dividends in cash, contact your Financial Advisor.

While the fund declares dividends daily and pays them monthly, the amounts are rounded to the nearest $0.01 on a daily basis with respect to each investor’s fund account. As a result, investors whose fund account balances earn daily dividends that total less than one half a cent on any given day will not accrue any dividends on that day.

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, and are expected to be taxed as ordinary income. Such dividends are not eligible for the reduced rate of tax that may apply to certain qualifying dividends on corporate stock. Dividends paid by the fund are also not expected to qualify as “exempt-interest dividends,” and will not be excludable from gross income by shareholders, because the fund is not expected to invest at least 50% of the value of its total assets in securities the interest on which is excludable from gross income.

Although dividends are generally treated as taxable to you in the year they are paid, dividends declared in October, November or December but paid in January are taxable as if they were paid in December.

Shareholders not subject to tax on their income will not be required to pay tax on amounts distributed to them. 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 until proceeds are withdrawn from the plan.

Some states and localities do not tax dividends that are attributable to interest on certain government securities under certain circumstances. However, these dividends may be subject to corporate franchise tax in some states.

The fund will tell you annually the character of dividends for tax reporting purposes. You will generally not recognize any gain or loss on the sale or exchange of your fund shares as long as the fund maintains a share price of $1.00.

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 may be required to withhold a 24% federal tax on all dividends payable to you

 

 

Taxable distributions to non-US shareholders will generally be subject to a 30% withholding tax (or lower applicable treaty rate). However, certain properly reported distributions paid by the fund that are attributable to “qualified interest income” (generally, interest that would not have been subject to US federal withholding tax at the source if received directly by a non-US shareholder) or short-term capital gain are

generally exempt from the 30% withholding tax to the extent the fund properly reports such distributions. “Qualified interest income” includes, in general, US source (1) bank deposit interest, (2) short-term original discount, (3) interest (including original issue discount, market discount, or acquisition discount) on an obligation which is in registered form, unless it is earned on an obligation issued by a corporation or partnership in which the fund is a 10-percent shareholder or is contingent interest, and (4) any interest-related dividend from another regulated investment company. Qualified interest income may also include interest with respect to loans that relate to US branches of non-US corporations to the extent such interest is treated as US source under applicable branch interest rules. Non-US source interest income is not eligible for exemption from US federal withholding tax, and distributions of non-US source income will be subject to the 30% US withholding tax unless reduced by an applicable tax treaty.

The fund is required to withhold US tax (at a 30% rate) on payments of taxable dividends made to certain shareholders that fail to comply (or be deemed compliant) with extensive reporting and withholding requirements designed to inform the US Department of the Treasury of US-owned foreign investment accounts. Shareholders may be requested to provide additional information to the fund to enable the fund to determine whether withholding is required.

The tax consequences to a non-US shareholder entitled to claim the benefits of an applicable tax treaty might differ from those described herein. Non-US shareholders are advised to consult their own tax advisors with respect to the particular tax consequences to them of investing in the fund. Shares of the fund held by a non-US shareholder at death will be considered situated within the United States and subject to US estate tax.

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 and other information

The fund is a “feeder fund” that invests in securities through an underlying master fund. The fund and the master fund have the same investment objective.

The fund’s complete schedule of portfolio holdings for the second and fourth quarters of each fiscal year will be filed with the SEC on Form N-CSR. The fund’s Forms N‑CSR are available on the SEC’s website at http://www.sec.gov. Additionally, you may obtain copies of semiannual and annual reports to shareholders from the fund upon request by calling 1‑800‑647 1568. The semiannual and annual reports for the fund will be posted on the fund’s website at https://www.ubs.com/usmoneymarketfunds.

The fund will disclose on UBS AM’s website, within five business days after the end of each month, a complete schedule of the Master Fund’s portfolio holdings and information regarding the weighted average maturity and weighted average life of the Master Fund. This information will be posted on the UBS website at the following internet address: https://www.ubs.com/usmoneymarketfunds. In addition, the fund will file with the SEC on Form N‑MFP, within five business days after the end of each month, more detailed portfolio holdings information. The fund’s Forms N‑MFP will be available on the SEC’s website; UBS AM’s website will also contain a

link to these filings. The UBS AM website will also disclose the following information for the fund as of the end of each business day for the previous six months: (1) the percentage of the fund’s total assets invested in daily and weekly liquid assets; (2) the fund’s daily net inflows and outflows; and (3) the fund’s current market-based net asset value per share to four decimal places, which is calculated using current market quotations (or an appropriate substitute that reflects current market conditions). (For purposes of transactions in shares of the fund, the price for shares will be the net asset value per share, calculated using the amortized cost method to two decimal places as further described in this prospectus and the related SAI.) Investors also may find additional information about the fund at the above referenced UBS website internet address.

Additionally, an abbreviated portfolio holdings report for the Master Fund is available on a weekly basis. (The abbreviated weekly portfolio holdings report contains less information about each holding.) This information will be posted on the UBS website at the following internet address: https://www.ubs.com/usmoneymarketfunds. Under

normal circumstances, the abbreviated report will be as of the last business day in a week and is expected to be posted by the Thursday or Friday of the following week. The weekly information will be posted to the website at least one day prior to other public dissemination.

The weekly portfolio holdings information postings will continue to remain available on the website, along with any more current holdings information, at least until the date on which the fund files its portfolio holdings information with the SEC on Forms N-CSR for the period that included the date as of which the website information is current. (For example, the fund files its annual financial statements for its most recent fiscal year ended April 30th with the SEC on Form N-CSR around the beginning of July. Weekly portfolio holdings information for periods ended April 30th could be removed from the website once the annual financial statements are filed, but not until then.)

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 on an investment in the fund (assuming reinvestment of all dividends and other 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 appears in the fund’s Form N-CSR. You may obtain copies of the fund’s Form N-CSR without charge by calling 1-888-647 1568.

© UBS 2026. All rights reserved.

Prospectus | August 28, 2026

Prospectus | August 28, 2026

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