# EDGAR Filing Document

**Accession Number:** 0001060517
**File Stem:** 0001193125-26-031758
**Filing Date:** 2026-1
**Character Count:** 328673
**Document Hash:** cb4aabb902ec62b5ae86e4f5f772a71b
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-031758.hdr.sgml**: 20260130

**ACCESSION NUMBER**: 0001193125-26-031758

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 6

**FILED AS OF DATE**: 20260130

**DATE AS OF CHANGE**: 20260130

**EFFECTIVENESS DATE**: 20260130

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** UBS Series Funds
- **CENTRAL INDEX KEY:** 0001060517

**ORGANIZATION NAME:**
- **EIN:** 134010447
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0430

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-52965
- **FILM NUMBER:** 26583307

**BUSINESS ADDRESS:**
- **STREET 1:** C/O UBS ASSET MANAGEMENT (AMERICAS) LLC
- **STREET 2:** 1285 AVENUE OF THE AMERICAS
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
- **BUSINESS PHONE:** 212-821-3000

**MAIL ADDRESS:**
- **STREET 1:** C/O UBS ASSET MANAGEMENT (AMERICAS) LLC
- **STREET 2:** 1285 AVENUE OF THE AMERICAS
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** UBS MONEY SERIES
- **DATE OF NAME CHANGE:** 20020716

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** BRINSON MONEY SERIES
- **DATE OF NAME CHANGE:** 20010625

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** MITCHELL HUTCHINS LIR MONEY SERIES
- **DATE OF NAME CHANGE:** 19990730

## Series and Classes Contracts Data

### UBS Select 100% US Treasury Institutional Fund (Series ID: S000084282)

---

|  |  |  |
|:---|:---|:---|
| Class Name           | Ticker Symbol | Class ID   |
| Token-Enabled Shares | TOKXX         | C000271489 |

---

## Series and Classes Contracts Data

### UBS Select 100% US Treasury Institutional Fund (Series ID: S000084282)

| Class ID   | Class Name           | Ticker Symbol   |
|:---|:---|:---|
| C000271489 | Token-Enabled Shares | TOKXX           |

![LOGO](g91760g54m60.jpg)

## Money Market Funds
Prospectus \| January 26, 2026

**Includes:** 

• UBS Select 100% US Treasury Institutional Fund

&nbsp;&nbsp;&nbsp;&nbsp;• Token-Enabled Shares: TOKXX

As with all mutual funds, the Securities and Exchange Commission has not approved or disapproved the funds' shares or determined whether this prospectus is complete or accurate. To state otherwise is a crime.

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

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Contents

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| | |
|:---|:---|
| **The fund** |  |
| *What every investor should know about the fund* |  |
| **Fund summary** |  |
| [UBS Select 100% US Treasury Institutional Fund](#tx91760_200) | 3 |
| **[More information about the fund](#tx91760_4)** | 9 |
| **Your investment** |  |
| *Information for managing your fund account* |  |
| [Managing your fund account](#tx91760_5) | 14 |
| —[Buying shares](#tx91760_5a) | 14 |
| —[Selling shares](#tx91760_12) | 15 |
| —[Exchanging shares](#tx91760_13) | 16 |
| —[Transfer of account limitations](#tx91760_14) | 16 |
| —[Additional information about your account](#tx91760_14a) | 17 |
| —[Market timing](#tx91760_15) | 17 |
| —[Pricing and valuation](#tx91760_15a) | 18 |
| **Additional information** |  |
| *Additional important information about the fund* |  |
| [Management](#tx91760_6) | 19 |
| [Dividends and taxes](#tx91760_7) | 20 |
| [Disclosure of portfolio holdings and other information](#tx91760_8) | 22 |
| [Financial highlights](#tx91760_9) | 24 |
| [Appendix A: Additional information regarding purchases and redemptions](#tx91760_10) | 25 |
| [Where to learn more about the fund](#tx91760_11) | Back cover |

---

**The fund is not a complete or balanced investment program.** 

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UBS Select 100% US Treasury Institutional Fund

Fund summary

**Investment objective** 

Maximum current income consistent with liquidity and the preservation of capital.

**Fees and expenses of the fund** 

These tables describe the fees and expenses that you may pay if you buy, hold and sell shares of the fund. You may pay other fees, such as fees to financial intermediaries, which are not reflected in the table or example below.

**Shareholder fees** *(fees paid directly from your investment)*

---

| |
|:---|
| Maximum front-end sales charge (load) imposed on purchases |
| Maximum deferred sales charge (load) |

---

**Annual fund operating expenses** *(expenses that you pay each year as a percentage of the value of your investment)\**

---

| | |
|:---|:---|
| | **Token-Enabled<br>Shares** |
| Management fees | 0.18% |
| Distribution and/or service (12b-1) fees |  |
| Other expenses<sup>1</sup> | 0.04 |
| Total annual fund operating expenses | 0.22 |
| Fee waiver/expense reimbursement<sup>2</sup> | 0.04 |
| Total annual fund operating expenses after fee waiver and/or expense reimbursement<sup>2</sup> | 0.18 |

---

\* The fund invests in securities through an underlying master fund, 100% US Treasury Master Fund. This table reflects the direct expenses of the fund and its share of expenses of 100% US Treasury Master Fund, including management fees allocated from 100% US Treasury Master Fund. Management fees are comprised of investment advisory and administration fees. 

<sup>1</sup> The Fund's "Other Expenses" have been estimated to reflect expenses to be incurred during the first fiscal year.

<sup>2</sup> The fund and UBS Asset Management (Americas) LLC ("UBS AM") have entered into a written fee waiver/expense reimbursement agreement pursuant to which UBS AM is contractually obligated to waive its management fees and/or reimburse the fund so that the fund's operating expenses through January 26, 2027 (excluding interest expense, if any, expenses related to shareholders' meetings and extraordinary items) would not exceed 0.18%. The fund has agreed to repay UBS AM for any waived management fees/reimbursed expenses to the extent that it can do so over the three years following such waived fees/reimbursed expenses without causing the fund's expenses in any of those three years to exceed the lesser of any applicable expense limit that is in place for the fund (i) at the time of the waiver or reimbursement, or (ii) at the time of recoupment. The fee waiver/expense reimbursement agreements may be terminated by the fund's board at any time and also will terminate automatically upon the expiration or termination of the fund's contract with UBS AM. Upon termination of the agreement, however, UBS AM's three year recoupment rights will survive. 

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**Example** 

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the fund's operating expenses remain the same.\*

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

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| | | | | |
|:---|:---|:---|:---|:---|
| | **1 year** | **3 years** | **5 years** | **10 years** |
| **UBS Select 100% US Treasury Institutional Fund** |  |  |  |  |
| &nbsp;&nbsp;&nbsp;&nbsp; Token-Enabled Shares | $18 | $67 | $120 | $276 |

---

\* Except that the expenses reflect the effects of the fund's fee waiver/expense reimbursement agreement for the first year only. The fund invests in securities through an underlying master fund, 100% US Treasury Master Fund. This table reflects the direct expenses of the fund and its share of expenses of 100% US Treasury Master Fund, including management fees allocated from 100% US Treasury Master Fund. Management fees are comprised of investment advisory and administration fees. 

**Principal strategies** 

**Principal investments** 

The fund is a money market fund and seeks to maintain a stable price of $1.00 per share. To do this, under normal circumstances, the fund invests exclusively in a diversified portfolio of high quality, US Treasury money market instruments and may also hold cash.

Money market instruments generally are short-term debt obligations. They also may include longer-term bonds that have variable interest rates or other special features (e.g., a put option) that give them the financial characteristics of short-term debt. In order to qualify as a "government money market fund" under federal regulations, 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 by cash and/or government securities); however, as noted above, the fund expects to further limit its investments, and under normal circumstances, the fund invests exclusively in a diversified portfolio of high quality, US Treasury money market instruments and may also hold cash. US Treasury money market instruments include Treasury bills, notes, and floating rate notes. Many US government money market instruments, including those in which the fund invests, pay income that is generally exempt from state and local income tax, although they may be subject to corporate franchise tax in some state. The fund generally seeks to invest in securities the income from which is considered "qualified interest income" under relevant tax law and guidance.

The Fund will generally hold a portion of its assets in cash for operational purposes.

The fund invests in securities through an underlying master fund. The fund and its corresponding master fund have the same objective. Unless otherwise indicated, references to the fund include the master fund.

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**Management process** 

UBS Asset Management (Americas) LLC ("UBS AM") acts as the investment advisor. As investment advisor, UBS AM makes the fund's investment decisions. UBS AM selects money market instruments for the fund based on its assessment of relative values and changes in market and economic conditions.

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.

**Principal risks** 

All investments carry a certain amount of risk, and the fund cannot guarantee that it will achieve its investment objective.

You could lose money by investing in the fund. Although the fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in the fund is not a bank account and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund's sponsor is not required to reimburse the Fund for losses, and you should not expect that the sponsor will provide financial support to the Fund at any time, including during periods of market stress.

Money market instruments generally have a low risk of loss, but they are not risk-free. The principal risks presented by an investment in the fund are:

**Credit risk:** Issuers of money market instruments may fail to make payments when due, or they may become less willing or less able to do so.

**Interest rate risk:** The value of the fund's investments generally will fall when short-term interest rates rise, and its yield will tend to lag behind prevailing rates. 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. The fund may face a heightened level of interest rate risk due to certain changes in general economic conditions, inflation and monetary policy, such as certain types of interest rate changes by the Federal Reserve. Any such changes could be sudden and could expose debt markets to significant volatility and reduced liquidity for fund investments.

**US Government securities risk:** There are different types of US government securities with different levels of credit risk, including the risk of default, depending on the nature of the particular government support for that security. Securities issued or guaranteed by the US Treasury are backed by the full faith and credit of the United States, but are guaranteed only as to the timely payment of interest and principal when held to maturity, and the market prices for such securities will fluctuate. Notwithstanding that these securities are backed by the full faith and credit of the United States, circumstances could arise that would prevent the timely payment of interest or principal, which could result in losses to the fund (e.g., Congressional debt ceiling impasses).

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**Market risk:** The risk that the market value of the fund's investments may fluctuate, sometimes rapidly or unpredictably, as the markets fluctuate, which may affect the fund's share price. Market risk may affect a single issuer, industry, or sector of the economy, or it may affect the market as a whole. Moreover, changing market, economic, political and social conditions in one country or geographic region could adversely impact market, economic, political and social conditions in other countries or regions.

**Liquidity risk:** Although the fund invests in a diversified portfolio of high quality instruments, the fund's investments may become less liquid as a result of market developments or adverse investor perception. If this happens, the fund's ability to redeem its shares for cash may be affected.

**Management risk:** The risk that the investment strategies, techniques and risk analyses employed by the advisor may not produce the desired results. 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.

**Technology risk:** Although the fund does not currently employ blockchain technology, financial intermediaries through whom shareholders purchase and redeem Token-Enabled Shares intend to employ blockchain technology to maintain a record or a mirror record of share ownership for their customers. A blockchain is a type of distributed ledger technology that records transactions between parties in a verifiable and append-only manner using cryptography. Transactions on the blockchain are verified and authenticated by computers on the network. The process of authenticating a transaction before it is recorded seeks to ensure that only valid and authorized transactions are permanently recorded on the blockchain in collections of transactions called "blocks." Blockchain networks are based upon software source code that establishes and governs their respective cryptographic systems for verifying transactions. Complex information technology and communications systems, such as blockchain networks, are subject to a number of different threats or risks (including operational, information security, cyber-attacks and related risks) that could adversely affect the fund, its shareholders and financial intermediaries through whom shareholders purchase and redeem Token-Enabled Shares of the fund. The use of distributed ledger technology, including blockchain, is relatively new and still evolving. The fund, its transfer agent, advisor, distributor and their affiliates will not be responsible for any loss in connection with the use of blockchain technology by a financial intermediary subject to applicable law. Shareholders should contact their financial intermediaries about whether or how they use blockchain technology and the associated risks.

**Performance** 

**Risk/return bar chart and table**

The performance information that follows shows the fund's performance information in a bar chart and an average annual total returns table for Institutional Shares of the fund, which is not offered in this

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prospectus. There is no performance information quoted for Token-Enabled Shares of the fund as Token-Enabled Shares have not completed a full calendar year of operations as of the date of this prospectus. Although Token-Enabled Shares are invested in the same portfolio of securities as Institutional Shares, returns for Token-Enabled Shares will differ from Institutional Shares to the extent that there may be any differing expenses of the classes.

The information provides some indication of the risks of investing in the fund by showing the fund's performance over its first calendar year of operations. The fund's past performance does not necessarily indicate how the fund will perform in the future.

**UBS Select 100% US Treasury Institutional Fund** 

**Annual total return of Institutional Shares (2025 was the fund's first full calendar year of operations)**![LOGO](g91760g10k08.jpg)

Best quarter during year shown—3Q 2025: 1.03%

Worst quarter during year shown—4Q 2025: 0.94%

Updated performance information is available (1) by contacting your Financial Advisor, (2) by calling 1-888-793 8637 (Option #1) and (3) on the fund's website at https://www.ubs.com/usmoneymarketfunds.

**Average annual total returns of Institutional Shares** (*for the periods ended December 31, 2025*)

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| | |
|:---|:---|
| One year | 4.07% |
| Life of fund (inception date March 13, 2024) | 4.47% |

---

**Investment advisor** 

UBS AM serves as the investment advisor to the fund.

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**Purchase & sale of fund shares** 

You may buy and sell fund shares through financial intermediaries who are authorized to accept purchase and sales orders on behalf of the fund. Although the fund does not currently employ blockchain technology, Token-Enabled Shares are expected to be purchased and held primarily through financial intermediaries that intend to use blockchain technology to maintain a record or a mirror record of share ownership for their customers. Purchases are not subject to a minimum investment level. Shares of the fund may be redeemed in the same manner as they were purchased (*i.e.*, through a financial intermediary). Shares can be purchased and redeemed on any business day on which the Federal Reserve Bank of New York, the New York Stock Exchange and the principal bond markets (as recommended by the Securities Industry and Financial Markets Association) are open.

**Tax information** 

The dividends and distributions you receive from the fund are taxable and will generally be taxed as ordinary income, capital gains or some combination of both, unless you hold shares through a tax-exempt account or plan, such as an individual retirement account or 401(k) plan, in which case dividends and distributions on your shares generally will be taxed when withdrawn from the tax-exempt account or plan.

**Payments to broker-dealers and other financial intermediaries** 

If you purchase the fund through a broker-dealer or other financial intermediary (such as a bank), UBS AM and/or its affiliates may pay the intermediary for the sale of fund shares and related services, or other shareholder services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the fund over another investment. Ask your financial advisor or visit your financial intermediary's website for more information.

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*UBS Series Funds* 

More information about the fund

**Additional information about the investment objective** 

The investment objective of the fund is non-fundamental and may be changed by the fund's board at any time without shareholder approval.

**Additional information about investment strategies** 

The fund seeks to achieve its investment objective by investing, under normal circumstances, exclusively in securities issued by the US Treasury and may also hold cash. Many US government money market instruments, including those in which the fund invests, pay income that is generally exempt from state and local income tax, although they may be subject to corporate franchise tax in some states. The fund may also hold cash, including cash earning interest held at the fund's custodian. Interest income received by the fund from cash held at the custodian would not qualify for the state and local income tax exemption applicable to certain dividends paid by the fund that are derived from interest income with respect to US government securities. 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.

The fund's board has determined that the fund will operate as a "government money market fund" under 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); however, as noted above, the fund expects to further limit its investments, and under normal circumstances, the fund invests exclusively in a diversified

portfolio of high quality, US Treasury money market instruments and may also hold cash. US Treasury money market instruments include Treasury bills, notes, and floating rate notes. As a government money market fund under Rule 2a-7, 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 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 with respect to liquidity fees, 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.)

The fund's policy to, under normal circumstances, invest exclusively in securities issued by the US Treasury is a non-fundamental policy. This means that this investment policy may be 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 this investment policy.

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

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*UBS Series Funds* 

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 fund may maintain a rating from one or more rating agencies that provide ratings on money market funds. There can be no assurance that the fund will maintain any particular rating or maintain it with a particular rating agency. To maintain a rating, UBS AM may manage the 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. As indicated below, not all of these risks apply to the fund. The fund(s) to which the main risks apply are noted 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.

**Credit risk.** Credit risk is the risk that the issuer or guarantor of money market instruments, or the counterparty to a 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 the highest quality investments are subject to some credit risk. The credit quality of an issuer or counterparty can change rapidly due to market developments and may affect the fund's share price.

**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.

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

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*UBS Series Funds* 

some or all of the fund's money market securities holdings.

**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 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 or 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 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 that are supported by the full faith and credit of the US government. In some cases, there is even the risk of default. For example, for asset-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

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*UBS Series Funds* 

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.

**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.

**Risk associated with the fund holding cash as a part of its investment program.** The fund will generally hold a portion of its assets in cash for operational purposes. Cash positions may hurt performance and may subject the fund to additional risks and costs, such as increased exposure to the custodian bank holding the assets and fees imposed for large cash balances. In addition, interest income received by the fund from cash held at the custodian would not qualify for the state and local income tax exemption applicable to certain dividends paid by the fund that are derived from interest income with respect to US government securities.

**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/Technology 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

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*UBS Series Funds* 

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.

Although the fund does not currently employ blockchain technology, financial intermediaries through whom shareholders purchase and redeem Token-Enabled Shares intend to employ blockchain technology to maintain a record or a mirror record

of share ownership for their customers. A blockchain is a type of distributed ledger technology that records transactions between parties in a verifiable and append-only manner using cryptography. Transactions on the blockchain are verified and authenticated by computers on the network. The process of authenticating a transaction before it is recorded seeks to ensure that only valid and authorized transactions are permanently recorded on the blockchain in collections of transactions called "blocks." Blockchain networks are based upon software source code that establishes and governs their respective cryptographic systems for verifying transactions. Complex information technology and communications systems, such as blockchain networks, are subject to a number of different threats or risks (including operational, information security, cyber-attacks and related risks) that could adversely affect the fund, its shareholders and financial intermediaries through whom shareholders purchase and redeem Token-Enabled Shares of the fund. The use of distributed ledger technology, including blockchain, is relatively new and still evolving. The fund, its transfer agent, advisor, distributor and their affiliates will not be responsible for any loss in connection with the use of blockchain technology by a financial intermediary subject to applicable law. Shareholders should contact their financial intermediaries about whether or how they use blockchain technology and the associated risks.

------

*UBS Series Funds* 

Managing your fund account

The following pages tell you how to buy, sell and exchange shares of the fund. The fund currently offers two classes of shares—Institutional Shares and Token-Enabled Shares. Only Token-Enabled Shares are offered in this prospectus.

As discussed further below, neither the fund nor its transfer agent directly employ blockchain technology. Financial intermediaries through whom you purchase and redeem Token-Enabled Shares intend to employ blockchain technology to maintain a record or a mirror record of share ownership for their customers. Such intermediaries are reflected on the fund's traditional book-entry recordkeeping system as the registered owner of the shares. You should contact your financial intermediary to learn about the terms and conditions associated with holding any "tokens" issued by such intermediaries.

Through your financial intermediary, you may be able to pledge or transfer your Token-Enabled Shares to authorized persons in transactions or arrangements that do not involve the fund or its transfer agent. The following section only addresses purchase, redemption and exchange orders directly with or through the fund and its transfer agent. You should contact your financial intermediary to learn about the process to pledge or transfer your Token-Enabled Shares to authorized persons.

**Buying shares** 

The fund accepts the settlement of purchase orders only in available federal funds deposited by a commercial bank in an account at a Federal Reserve Bank, which can be transferred to a similar account of another bank in one day and may be made immediately available to the fund through its custodian.

You may buy fund shares through financial intermediaries who are authorized to accept pur-

chase orders on behalf of the fund. If you buy fund shares through a financial intermediary who holds them in its own name on your behalf (in "street name"), the financial intermediary is responsible for sending the order to the transfer agent. You may not call the fund's transfer agent directly if your shares are held in "street name," but should direct all your requests to buy or sell shares directly to your financial intermediary.

Although the fund does not currently employ blockchain technology, Token-Enabled Shares are expected to be purchased and held primarily through financial intermediaries that intend to use blockchain technology to maintain a record or a mirror record of share ownership for their customers.

You buy shares at the net asset value next determined after receipt of your purchase order in good form by the transfer agent (or, if applicable, by a financial intermediary). The fund must receive payment on the same day. Your purchase order will be effective only if (1) you or your financial intermediary wires payment in federal funds on the same business day that you place your order, and (2) the wire is actually credited to the fund's bank account by a Federal Reserve Bank on that day. Otherwise, the order will be rejected. A business day is any day on which the Federal Reserve Bank of New York, the New York Stock Exchange ("NYSE"), and the principal bond markets (as recommended by the Securities Industry and Financial Markets Association ("SIFMA")) are open. (Holidays are listed on Appendix A to this prospectus.)

The chart below shows processing times by which orders received by the fund's transfer agent will normally be executed. All times shown below repre-

------

*UBS Series Funds* 

sent Eastern time. Financial intermediaries may impose additional guidelines for when orders must be placed.

---

| | |
|:---|:---|
| **If a purchase order is received:** | **The order will normally<br>be executed as of:** |
| By 9:00 a.m. | 9:00 a.m. |
| After 9:00 a.m. and<br> before 10:00 a.m. | 10:00 a.m. |
| After 10:00 a.m. and<br> before 11:00 a.m. | 11:00 a.m. |
| After 11:00 a.m. and<br> before 12:00 (noon) | 12:00 (noon) |
| After 12:00 (noon) and<br> before 1:00 p.m. | 1:00 p.m. |
| After 1:00 p.m. and<br> before 2:00 p.m. | 2:00 p.m. |
| After 2:00 p.m. and<br> before 2:30 p.m. | 2:30 p.m. |

---

The fund may advance the time by which orders to buy or sell its shares must be received by the transfer agent on any day that the NYSE closes early because trading has been halted for the day. The fund will advance the final time by which orders to buy or sell shares must be received by the transfer agent to 12:00 p.m. (noon) (Eastern time) on those days that SIFMA has recommended that the bond markets close early. Appendix A to this prospectus lists the SIFMA US "early closing" holiday recommendations schedule for the remainder of 2025 and for 2026. These "early closing" days most often occur on a business day prior to a national holiday.

The fund, UBS AM and UBS Asset Management (US) Inc. ("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. UBS AM (US) may return without notice money wired to the

fund if the investor fails to place a corresponding share purchase order.

**Minimum investment.** Initial purchases of the fund are not subject to a minimum

The fund may change its minimum investment policy at any time. Investments must be denominated in US dollars.

If your fund account balance has fallen below the respective minimum initial investment amount indicated above, UBS AM (US) reserves the right to reject your purchase order to add to the account unless the account balance will be at least such amount after that purchase.

**Selling shares** 

You may sell your shares through financial intermediaries that are authorized to accept redemption requests. If you sell your shares through a financial intermediary who holds them in its own name on your behalf (in "street name"), the financial intermediary is responsible for sending the order to the transfer agent. You may not call the fund's transfer agent directly if your shares are held in "street name," but should direct all your requests to buy or sell shares directly to your financial intermediary.

You sell shares based upon the net asset value next determined after receipt of your redemption order in good form by the transfer agent (or, if applicable, by a financial intermediary). A redemption order will not be in good form unless it is received by the fund's transfer agent prior to the deadlines set forth below. Orders that are not received in good form will not be executed at the net asset value next determined after receipt of the order. Orders to sell shares of the fund received by the fund's transfer agent before 9:00 a.m. (Eastern

------

*UBS Series Funds* 

time) will normally be executed as of 9:00 a.m. (Eastern time).

The chart below shows processing times by which orders received by the fund's transfer agent will normally be executed. All times shown below represent Eastern time.

---

| | |
|:---|:---|
| **If a redemption order is received:** | **The order will normally<br>be executed as of:** |
| By 9:00 a.m. | 9:00 a.m. |
| After 9:00 a.m. and<br> before 10:00 a.m. | 10:00 a.m. |
| After 10:00 a.m. and<br> before 11:00 a.m. | 11:00 a.m. |
| After 11:00 a.m. and<br> before 12:00 (noon) | 12:00 (noon) |
| After 12:00 (noon) and<br> before 1:00 p.m. | 1:00 p.m. |
| After 1:00 p.m. and<br> before 2:00 p.m. | 2:00 p.m. |
| After 2:00 p.m. and<br> before 2:30 p.m. | 2:30 p.m. |

---

As noted above under "Buying shares," the fund may advance the time for the transfer agent's receipt of orders to sell shares (*e.g.*, days on which securities markets close early prior to a national holiday).

Your sales proceeds will be paid in federal funds. Proceeds from the sale will be wired to one or more accounts you have designated. If a redemption order is received by 2:30 p.m. (Eastern time), the proceeds ordinarily will be transmitted in federal funds on the same day. If you sell all the shares you own, dividends accrued for the month to date will be paid in federal funds and wired or deposited on the same day to the accounts noted above.

If the transfer agent receives your order to sell shares late in the day, it will process your order and

initiate a wire. However, your bank account or your account at your financial intermediary may not receive the proceeds in a timely manner if a Federal Reserve Bank is experiencing delay in transfer of funds. Neither the fund, UBS AM, UBS AM (US), a financial intermediary nor the transfer agent is responsible for the performance of a bank or any of its intermediaries.

Typically, redemptions of fund shares will be made by the fund wiring cash payments or deposit into your account. The fund typically expect 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.

If you have additional questions on selling shares, you should contact your investment professional at your financial intermediary.

**Exchanging shares** 

You may not exchange Token-Enabled Shares of the fund for shares of other funds.

**Transfer of account limitations** 

If you hold your shares with UBS Financial Services Inc. or another 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

------

*UBS Series Funds* 

with the fund's principal underwriter. Should you have any questions regarding the portability of your fund shares, please contact your broker or Financial Advisor.

**Additional information about your account** 

You will receive a confirmation of your initial purchase of fund shares, and subsequent transactions may be reported on periodic account statements. These periodic statements may be sent monthly except that, if your only fund activity in a quarter was reinvestment of dividends, the activity may be reported on a quarterly rather than a monthly statement.

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 to you in satisfaction thereof no later than the business day following the redemption request (under normal circumstances, on the same day). 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 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 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.

A financial intermediary buying or selling shares for its customers is responsible for transmitting orders to the transfer agent in accordance with its customer agreements and the procedures noted above.

UBS AM (US) (not the fund) also may pay fees to entities that make shares of the fund available to others. The amount of these fees will be negotiated between UBS AM (US) and the entity.

**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 gener-

------

*UBS Series Funds* 

ally 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 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, 100% US Treasury 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 net asset value per share of the fund is expected to be $1.00, although this value is not guaranteed.

The net asset value per share of the fund is normally determined seven times each business day, every hour on the hour (except for its last daily pricing), beginning at 9:00 a.m. (Eastern time) and concluding at 2:30 p.m. (Eastern time).

Your price for buying or selling shares will be based upon the net asset value that is next calculated after the fund receives your order.

On any day that the fund determines to advance the time by which orders to buy or sell its shares must be received by the transfer agent as described above under "Buying shares," the time for determination of the fund's net asset value per share will be as of the same time the fund has determined to cease accepting orders to buy or sell its shares. The fund will not price its shares again on that business day even though it normally prices its shares more frequently.

The fund's board has designated UBS AM as the valuation designee pursuant to Rule 2a-5 under the Investment Company Act of 1940, as amended, 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

------

*UBS Series Funds* 

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 the 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 100% US Treasury 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.

UBS AM is a Delaware limited liability company with its principal business offices located at One North

Wacker Drive, Chicago, IL 60606, and at 1285 Avenue of the Americas, New York, NY 10019. UBS AM is an investment adviser registered with the SEC. UBS AM is an indirect asset management subsidiary of UBS Group AG ("UBS"). As of September 30, 2025, UBS AM had approximately $590 billion in assets under management. UBS AM is a member of the UBS Asset Management Division, which had approximately $2.0 trillion in assets under management worldwide as of September 30, 2025. UBS is an internationally diversified organization headquartered in Zurich, Switzerland with operations in many areas of the financial services group of industries.

**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:

---

| | |
|:---|:---|
| $0 – $30 billion | 0.1000% |
| Above $30 billion up to $40 billion | 0.0975% |
| Above $40 billion up to $50 billion | 0.0950% |
| Above $50 billion up to $60 billion | 0.0925% |
| Above $60 billion | 0.0900% |

---

UBS AM's contract fee for the administrative services it provides to the feeder fund is 0.08% of the feeder fund's average daily net assets.

UBS AM received an effective fee of 0.14% of the average daily net assets of the fund for its services as investment advisor and administrator in the fund's last fiscal year which ended April 30, 2025 (includes fees allocated from related master fund, net of voluntary and/or contractual fee waivers/expense reimbursements, if any).

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

------

*UBS Series Funds* 

guarantee that UBS AM would continue to voluntarily waive a portion of its fees. Waivers may impact a fund's performance.

A discussion regarding the basis for 100% US Treasury Master Fund's board's approval of the Management Agreement between UBS AM and Master Trust with respect to 100% US Treasury Master Fund is available in the fund's Form N-CSR for the fiscal period ended October 31, 2025.

**Master-feeder structure** 

The fund is a "feeder fund" that invests all of its assets in a "master fund"—100% US Treasury 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 their 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 (if you purchased your shares through a financial intermediary) or the transfer agent (if you purchased your shares directly).

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,

------

*UBS Series Funds* 

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. Dividends that are attributable to interest income received by the fund from cash held at the custodian would not qualify for this exemption.

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

• if you fail to provide the fund or UBS Financial Services Inc. with your correct taxpayer identification number on Form W-9 (for US citizens and resident aliens) or to make required certifications, or

• if you have been notified by the IRS that you are subject to backup withholding.

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.

------

*UBS Series Funds* 

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 resident shareholder entitled to claim the benefits of an applicable tax treaty might differ from those described herein. Non-US resident 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 is filed with the SEC on Form N-CSR. The fund's Forms N-CSR will be available on the SEC's website at http://www.sec.gov. Additionally, you may obtain copies of Form N-CSR from the fund upon request by calling 1-800-647 1568. The Form N-CSR 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 the 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.

------

*UBS Series Funds* 

Additionally, an abbreviated portfolio holdings report for the master fund in which the fund invests 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.

------

Financial highlights

The following financial highlights table is intended to help you understand the financial performance for UBS Select 100% US Treasury Institutional Fund 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 a fund (assuming reinvestment of all dividends and other distributions). Because Token-Enabled Shares had not commenced operations as of the end of the fund's previous fiscal year, financial highlights are not available. The financial highlights shown are those of the fund's Institutional Shares. Only Token-Enabled Shares are offered in this prospectus.

The information in the financial highlights through April 30, 2025, 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 for the fiscal periods ended April 30, 2025, and April 30, 2024, respectively. The information in the financial highlights for the six months ended October 31, 2025, is unaudited and appears in the fund's Form N-CSR for the fiscal period ended October 31, 2025. You may obtain copies of the fund's Form N-CSR without charge by calling 1-888-547 FUND.

Selected data for a share of beneficial interest outstanding throughout each period is presented below:

---

| | | | |
|:---|:---|:---|:---|
|  | **Six months ended<br>October 31, 2025<br>(unaudited)** | | **For the period from<br>March 13, 2024<sup>1</sup> to<br>April 30, 2024** |
| | **Six months ended<br>October 31, 2025<br>(unaudited)** | **Year ended April 30,**<br>**2025** | **For the period from<br>March 13, 2024<sup>1</sup> to<br>April 30, 2024** |
| **Net asset value, beginning of period** | $1.00 | $1.00 | $1.00 |
| Net investment income (loss) | 0.021 | 0.047 | 0.007 |
| Net realized and unrealized gain (loss) | 0.000<sup>2</sup> | 0.000<sup>2</sup> |  |
| Net increase (decrease) from operations | 0.021 | 0.047 | 0.007 |
| Dividends from net investment income | (0.021) | (0.047) | (0.007) |
| Distributions from net realized gains |  |  |  |
| Total dividends and distributions | (0.021) | (0.047) | (0.007) |
| **Net asset value, end of period** | $1.00 | $1.00 | $1.00 |
| **Total investment return<sup>3</sup>** | 2.05% | 4.66% | 0.69% |
| **Ratios to average net assets:** |  |  |  |
| Expenses before fee waivers /Trustees' fees reimbursements<sup>4</sup> | 0.19%<sup>5</sup> | 0.22% | 3.08%<sup>5</sup> |
| Expenses after fee waivers /Trustees' fees reimbursements<sup>4</sup> | 0.18%<sup>5</sup> | 0.18% | 0.18%<sup>5</sup> |
| Net investment income (loss)<sup>4</sup> | 4.08%<sup>5</sup> | 4.44% | 5.18%<sup>5</sup> |
| **Supplemental data:** |  |  |  |
| Net assets, end of period (000's) | $7411024 | $6347614 | $8380 |

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<sup>1</sup> Commencement of operations.

<sup>2</sup> Amount represents less than $0.0005 or $(0.0005) per share. 

<sup>3</sup> Total investment return is calculated assuming a $10,000 investment on the first day of each period reported, reinvestment of all dividends and other distributions, if any, at net asset value on the payable dates, and a sale at net asset value on the last day of each period reported. Total investment return for the period of less than one year has not been annualized. Returns do not reflect the deduction of taxes that a shareholder would pay on Fund distributions. 

<sup>4</sup> Ratios include the Fund's share of income, expenses and expense waivers allocated from the Master Fund.

<sup>5</sup> Annualized.

------

*UBS Series Funds: Appendix A* 

Additional information regarding purchases and redemptions

The fund is open for business each day that the Federal Reserve Bank of New York, the New York Stock Exchange ("NYSE") and the principal bond markets (as recommended by the Securities Industry and Financial Markets Association ("SIFMA")) are open. One or more of these will be closed on the observance of the holidays listed below. The fund will advance the final time by which orders to buy or sell shares must be received by the transfer agent to 12:00 p.m. (noon) (Eastern time) on those days that SIFMA has recommended that the bond markets close early. The normal deadline by which orders to buy or sell shares of the fund must be received by the transfer agent is 2:30 p.m. (Eastern time). Those days SIFMA has recommended that the bond markets close early remaining through 2026 are listed below.

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| | |
|:---|:---|
| **Holidays (observed)** | **Early close** |
| Presidents Day (February 16, 2026) |  |
| Good Friday (early close only—April 3, 2026) | April 3, 2026 |
| Memorial Day (May 25, 2026) | May 22, 2026 |
| Juneteenth (June 19, 2026) |  |
| Independence Day (July 3, 2026) | July 2, 2026 |
| Labor Day (September 7, 2026) |  |
| Columbus Day (October 12, 2026) |  |
| Veterans Day (November 11, 2026) |  |
| Thanksgiving Day (November 26, 2026) | November 27, 2026 |
| Christmas Day (December 25, 2026) | December 24, 2026 |
| New Year's Day (January 1, 2027) | December 31, 2026 |

---

------

If you want more information about the fund, the following documents are available free of charge upon request:

**Annual/semiannual reports and Forms N-CSR Filed with the SEC** 

Additional information about the fund's investments is available in the fund's annual and semiannual reports to shareholders and Forms N-CSR filed with the SEC. In Forms N-CSR, you will find the fund's annual and semi-annual financial statements.

**Statement of Additional Information (SAI)** 

The fund's SAI provides more detailed information about the fund and is incorporated by reference into this prospectus (*i.e.,* it is legally a part of this prospectus).

You may discuss your questions about the fund by contacting your Financial Advisor. You may obtain free copies of the fund's annual and semiannual reports and its SAI and other information such as the fund financial statements by contacting the fund directly at 1-800-647 1568. The fund's annual and semiannual reports and its SAI and other information such as the fund financial statements will also be posted on the UBS website at the following internet address: https://www.ubs.com/usmoneymarketfunds. You may also request other information about the fund and make shareholder inquiries via the telephone number above.

You can get copies of reports and other information about the fund:

• For a fee, by electronic request at publicinfo@sec.gov; or

• Free, from the EDGAR database on the SEC's Internet website at http://www.sec.gov.

UBS Series Funds

—UBS Select 100% US Treasury Institutional Fund

Investment Company Act File No. 811-08767© UBS 2026. All rights reserved.

S1938

![LOGO](g91760g40m50.jpg)

![LOGO](g91760g40m50.jpg)

Money Market Funds

Prospectus \| January 26, 2026

**Includes:** 

• UBS Select 100% US Treasury Institutional Fund

&nbsp;&nbsp;&nbsp;&nbsp;• Token-Enabled Shares

------

![LOGO](g788557mm_k.jpg)

Money Market Funds

Statement of Additional Information \| January 26, 2026 for Token-Enabled

Shares of UBS Select 100% US Treasury Institutional Fund, and August 28, 2025, as revised January 26, 2026 for each other fund and share class

1285 Avenue of the Americas,

New York, NY 10019

**Includes:** 

• UBS Select Government Institutional Fund: SEGXX

• UBS Select Treasury Institutional Fund: SETXX

• UBS Select 100% US Treasury Institutional Fund

&nbsp;&nbsp;&nbsp;&nbsp;• Institutional Shares: SIOXX

&nbsp;&nbsp;&nbsp;&nbsp;• Token-Enabled Shares: TOKXX

• UBS Select Government Preferred Fund: SGPXX

• UBS Select Treasury Preferred Fund: STPXX

• UBS Select 100% US Treasury Preferred Fund

&nbsp;&nbsp;&nbsp;&nbsp;• Class T: SOPXX

&nbsp;&nbsp;&nbsp;&nbsp;• Class P: STAXX

• UBS Prime Reserves Fund: UPRXX

• UBS Prime Preferred Fund: UPPXX

The eight funds named above (together, the "funds") are diversified series of UBS Series Funds (the "Trust"), a professionally managed open-end investment company. Each fund is a "feeder fund" that invests all of its assets in a corresponding master fund (each, a "master fund") with the same objective as the fund.

UBS Asset Management (Americas) LLC ("UBS AM") is the investment adviser and administrator for the master funds and the administrator for the feeder funds. UBS Asset Management (US) Inc. ("UBS AM (US)") serves as principal underwriter for the funds. UBS AM and UBS AM (US) are indirect wholly owned subsidiaries of UBS Group AG.

The audited financial statements of the funds are incorporated into this Statement of Additional Information ("SAI") by reference to the funds' most recent [Form N-CSR](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001060517/000119312525156261/d920425dncsr.htm) for its fiscal year ended April 30, 2025. The funds' semi-annual financial statements as of and for the fiscal period ended October 31, 2025 are unaudited and are incorporated herein by reference to the funds' most recent [Form N-CSR](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/1060517/000119312526008851/d31005dncsrs.htm) for their fiscal period ended October 31, 2025. You may obtain an additional copy of the funds' financial statements without charge by calling toll-free 1-888-547 FUND.

This SAI is not a prospectus and should be read only in conjunction with the respective funds' current prospectuses dated August 28, 2025, or January 26, 2026, as applicable. A copy of a prospectus may be obtained by calling a financial intermediary through which shares may be purchased or by calling toll-free 1-888-547 FUND. The prospectus also contains more complete information about the relevant fund. You should read it carefully before investing. This SAI is dated January 26, 2026 for Token-Enabled Shares of UBS Select 100% US Treasury Institutional Fund, and August 28, 2025, as revised January 26, 2026 for each other fund and share class.

------

---

| | |
|:---|:---|
| **Table of contents** | **Page** |
| [The funds and their investment policies](#sai78855_1) | 3 |
| [The funds' investments, related risks and limitations](#sai78855_2) | 6 |
| [Disclosure of portfolio holdings](#sai78855_3) | 21 |
| [Organization of the Trust; trustees and officers; principal holders and management ownership of securities](#sai78855_4) | 25 |
| [Investment advisory, administration and principal underwriting arrangements](#sai78855_5) | 35 |
| [Portfolio transactions](#sai78855_6) | 43 |
| [Additional information regarding redemptions](#sai78855_7) | 45 |
| [Valuation of shares](#sai78855_8) | 45 |
| [Taxes](#sai78855_9) | 47 |
| [Potential conflicts of interest](#sai78855_10) | 49 |
| [Other information](#sai78855_11) | 57 |
| [Financial statements](#sai78855_12) | 58 |

---

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The funds and their investment policies

Each fund's (except UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund) investment objective may not be changed without shareholder approval. The investment objective of each of UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund is non-fundamental and may be changed by the relevant fund's board at any time without shareholder approval. Except where noted, the investment policies of each fund may be changed by its board without shareholder approval.

Each fund invests in securities through an underlying master fund. Each fund and its corresponding master fund have the same objective. Unless otherwise indicated, references to a fund include its corresponding master fund. As with other mutual funds, there is no assurance that a fund will achieve its investment objective.

Each fund is a money market fund. Each of the funds seeks to maintain a stable price of $1.00 per share using amortized cost-based pricing. UBS Prime Reserves Fund and UBS Prime Preferred Fund are available only to investors who qualify for investments in "retail" money market funds consistent with Rule 2a-7 under the Investment Company Act of 1940, as amended ("Investment Company Act") and related US Securities and Exchange Commission ("SEC") staff guidance (*e.g.*, beneficial owners who are natural persons). Each fund invests in high quality money market instruments that have, or are deemed to have, remaining maturities of 13 months or less. Money market instruments include short-term debt-obligations. They also include longer term securities that have variable interest rates or other special features that give them the financial characteristics of short-term debt. Each fund maintains a dollar-weighted average portfolio maturity of 60 days or less; each fund maintains a dollar-weighted average life for its portfolio of 120 days or less.

Each fund may purchase only those obligations that UBS AM determines, pursuant to procedures adopted by the board, are "eligible securities" as defined in Rule 2a-7 under the Investment Company Act.

**UBS Prime Reserves Fund and UBS Prime Preferred Fund.** Each fund's investment objective is to earn maximum current income consistent with liquidity and the preservation of capital. Each fund's investments include (1) US and non-US government securities, (2) obligations of issuers in the financial services group of industries, (3) commercial paper and other short-term obligations of US and non-US corporations, partnerships, trusts and similar entities, (4) funding agreements and other insurance company obligations, (5) repurchase agreements, (6) investment company securities, and (7) municipal money market instruments.

Each fund may invest in obligations (including certificates of deposit, bankers' acceptances, time deposits and similar obligations) of US and non-US banks only if the institution has total assets at the time of purchase in excess of $1.5 billion. Each fund's investments in non-negotiable time deposits of these institutions will be considered illiquid if they have maturities greater than seven calendar days.

Each fund generally may invest no more than 5% of its total assets in the securities of a single issuer (other than US government securities), except that the fund may invest up to 25% of its total assets in securities of a single issuer for a period of up to three business days. Each fund may purchase only US dollar denominated obligations of non-US issuers.

Each fund will, under normal circumstances, invest more than 25% of its total assets in the financial services group of industries. Each fund may, however, invest less than 25% of its total assets in this group of industries as a temporary defensive measure.

Each fund will not acquire any illiquid security (as defined below) if, immediately after the acquisition, the fund would have invested more than 5% of its total assets in illiquid securities. Each fund also will comply with the daily and weekly liquidity requirements set forth in Rule 2a-7 of the Investment Company Act and, as such, must maintain

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a portion of its assets in cash or securities that can readily be converted into cash, which may have a negative effect on the fund's yield. Each fund may purchase securities on a when-issued or delayed delivery basis in accordance with Rule 18f-4 under the Investment Company Act ("Rule 18f-4"). Each fund may lend its portfolio securities to qualified broker-dealers or institutional investors in an amount up to 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. Each fund may borrow from banks or through reverse repurchase agreements for temporary purposes, but not in excess of 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. The costs associated with borrowing may reduce each fund's net income. See "The funds' investments, related risks and limitations—Investment limitations of the funds" for more information regarding borrowing. Each fund may invest in the securities of other investment companies, including money market funds advised by UBS AM.

**UBS Select Treasury Institutional Fund and UBS Select Treasury Preferred Fund.** Each fund's investment objective is to earn maximum current income consistent with liquidity and the preservation of capital. Under normal circumstances, each fund invests at least 80% of its net assets (plus the amount of any borrowing for investment purposes) in securities issued by the US Treasury and repurchase agreements relating to those instruments. For purposes of this policy, repurchase agreements are those that are collateralized fully by securities issued by the US Treasury and cash. Each fund may also invest in the securities of other investment companies that invest in these instruments. Each fund's 80% policy, as described above, is a "non-fundamental" policy. This means that this investment policy may be changed by each fund's board without shareholder approval. However, each 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.

The funds' board has determined that each fund will operate as a "government money market fund" under Rule 2a-7 of the Investment Company Act. Therefore, in addition to the 80% policy referenced above, each 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" under Rule 2a-7, each 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, each 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.)

Each fund will not acquire any illiquid security (as defined below) if, immediately after the acquisition, the fund would have invested more than 5% of its total assets in illiquid securities. Each fund also will comply with the daily and weekly liquidity requirements set forth in Rule 2a-7 of the Investment Company Act and, as such, must maintain a portion of its assets in cash or securities that can readily be converted into cash, which may have a negative effect on the fund's yield. Each fund may purchase securities on a when-issued or delayed delivery basis in accordance with Rule 18f-4. Each fund may lend its portfolio securities to qualified broker-dealers or institutional investors in an amount up to 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. Each fund may borrow from banks or through reverse repurchase agreements for temporary purposes, but not in excess of 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. The costs associated with borrowing may reduce each fund's net income. See "The funds' investments, related risks and limitations—Investment limitations of the funds" for more information regarding borrowing. Each fund may invest in the securities of other investment companies, including money market funds advised by UBS AM.

**UBS Select Government Institutional Fund and UBS Select Government Preferred Fund.** Each fund's investment objective is to earn maximum current income consistent with liquidity and the preservation of capital. Under normal circumstances, each fund invests at least 80% of its net assets in US government securities, including government securities subject to repurchase agreements. US government securities include direct obligations of the US Treasury (such as Treasury bills, notes or bonds) and obligations issued or guaranteed as to principal and interest (but not as to market value) by the US government, its agencies or its instrumentalities. Government securities subject to

------

repurchase agreements include repurchase agreements that are collateralized fully by government securities. Each fund may also invest in the securities of other investment companies that invest in these instruments. Each fund's 80% policy, as described above, is a "non-fundamental" policy. This means that this investment policy may be changed by each fund's board without shareholder approval. However, each 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.

Each fund's board has determined that the fund will operate as a "government money market fund" under Rule 2a-7 of the Investment Company Act. Therefore, in addition to the 80% policy referenced above, each 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" under Rule 2a-7, each 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, each 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 a fund's policy and have the opportunity to redeem their shares in accordance with Rule 2a-7 before the policy change became effective.)

Each fund will not acquire any illiquid security (as defined below) if, immediately after the acquisition, the fund would have invested more than 5% of its total assets in illiquid securities. Each fund also will comply with the daily and weekly liquidity requirements set forth in Rule 2a-7 of the Investment Company Act and, as such, must maintain a portion of its assets in cash or securities that can readily be converted into cash, which may have a negative effect on a fund's yield. Each fund may purchase securities on a when-issued or delayed delivery basis in accordance with Rule 18f-4. Each fund may lend its portfolio securities to qualified broker-dealers or institutional investors in an amount up to 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. Each fund may borrow from banks or through reverse repurchase agreements for temporary purposes, but not in excess of 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. The costs associated with borrowing may reduce a fund's net income. See "The funds' investments, related risks and limitations—Investment limitations" for more information regarding borrowing. Each fund may invest in the securities of other investment companies, including money market funds advised by UBS AM.

**UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund.** Each fund's investment objective is to earn maximum current income consistent with liquidity and the preservation of capital. Under normal circumstances, each fund invests exclusively in a diversified portfolio of high quality, US Treasury money market instruments and may also hold cash. Money market instruments generally are short-term debt obligations and similar securities. They also may include longer-term bonds that have variable interest rates or other special features (e.g., a put option) that give them the financial characteristics of short-term debt. Many US government money market instruments pay income that is generally exempt from state and local income tax, although they may be subject to corporate franchise tax in some states. Each fund may hold cash, including cash earning interest held at the fund's custodian. Each fund generally seeks to invest in securities the income from which is considered "qualified interest income" under relevant tax law and guidance.

The funds' board has determined that each fund will operate as a "government money market fund" under Rule 2a-7 of the Investment Company Act. Therefore, each 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); however, as noted above, the fund expects to further limit its investments, and under normal circumstances, the fund invests exclusively in a diversified portfolio of high quality, US Treasury money market instruments and may also hold cash. As a "government money market fund" under Rule 2a-7, each 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 which might apply to other types of funds under certain circumstances. (In conformance with Rule 2a-7, each 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.)

Each fund will not acquire any illiquid security (as defined below) if, immediately after the acquisition, the fund would have invested more than 5% of its total assets in illiquid securities. Each fund also will comply with the daily and weekly liquidity requirements set forth in Rule 2a-7 of the Investment Company Act and, as such, must maintain a portion of its assets in cash or securities that can readily be converted into cash, which may have a negative effect on the fund's yield. Each fund may purchase securities on a when-issued or delayed delivery basis in accordance with Rule 18f-4. Each fund may lend its portfolio securities to qualified broker-dealers or institutional investors in an amount up to 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. Each fund may borrow from banks or through reverse repurchase agreements for temporary purposes, but not in excess of 33<sup>1</sup>⁄<sub>3</sub>% of its total assets. The costs associated with borrowing may reduce each fund's net income. See "The funds' investments, related risks and limitations—Investment limitations of the funds" for more information regarding borrowing. Each fund may invest in the securities of other investment companies, including money market funds advised by UBS AM.

The funds' investments, related risks and limitations

The following supplements the information contained in the relevant fund's prospectus(es) and above concerning each fund's investments, related risks and limitations. Except as otherwise indicated in the prospectus or the SAI, the funds have established no policy limitations on their ability to use the investments or techniques discussed in these documents. New forms of money market instruments continue to be developed. The funds, through their corresponding master funds, may invest in these instruments to the extent consistent with their investment objectives and strategies.

**Yields and quality of money market instruments.** The yields on the money market instruments in which the funds invest are dependent on a variety of factors, including general money market conditions, conditions in the particular market for the obligation, the financial condition of the issuer, the size of the offering, the maturity of the obligation and the ratings of the issue. The ratings assigned by rating agencies represent their opinions as to the quality of the obligations they undertake to rate. Ratings, however, are general and are not absolute standards of quality. Consequently, obligations with the same rating, maturity and interest rate may have different market prices.

Subsequent to its purchase, a security held by a fund may experience a default, cease to be an eligible security (*e.g.*, no longer presents minimal credit risks), or an event of insolvency may occur with respect to the issuer. In such cases, a fund will dispose of the security as soon as practicable consistent with achieving an orderly disposition of the security, by sale, exercise of any demand feature or otherwise, absent a finding by the fund's board that disposal of the security would not be in the best interests of the fund (which determination may take into account, among other factors, market conditions that could affect the orderly disposition of the security).

**US Government securities.** US government securities include direct obligations of the US Treasury (such as Treasury bills, notes or bonds) and obligations issued or guaranteed as to principal and interest (but not as to market value) by the US government, its agencies or its instrumentalities. These US government securities may include mortgage-backed securities issued or guaranteed by government agencies or government-sponsored enterprises, that are not guaranteed or insured by the US government. Other US government securities may be backed by the full faith and credit of the US government or supported primarily or solely by the creditworthiness of the government-related issuer or, in the case of mortgage-backed securities, by pools of assets.

Securities issued by agencies and instrumentalities of the US government that are supported by the full faith and credit of the United States, such as securities issued by the Federal Housing Administration and the Government National Mortgage Association, present little credit risk. Other securities issued by agencies and instrumentalities sponsored by the US government that are supported only by the issuer's right to borrow from the US Treasury, subject to certain

------

limitations, such as securities issued by Federal Home Loan Banks, and securities issued by agencies and instrumentalities sponsored by the US government that are supported only by the credit of the issuing agencies are subject to a greater degree of credit risk. The Federal Home Loan Mortgage Corporation ("Freddie Mac") and the Federal National Mortgage Association ("Fannie Mae") historically were agencies sponsored by the US government that were supported by the credit of the issuing agencies and not backed by the full faith and credit of the United States. However, on September 7, 2008, due to the value of Freddie Mac's and Fannie Mae's securities falling sharply and concerns that the firms did not have sufficient capital to offset losses resulting from the mortgage crisis, the Federal Housing Finance Agency ("FHFA") placed Freddie Mac and Fannie Mae into conservatorship and stepped into the shoes of and succeeded to all of the rights of their shareholders. In addition to the conservatorship, the US government has taken various steps to provide additional financial support to Freddie Mac and Fannie Mae, including by having the FHFA (as conservator of Fannie Mae and Freddie Mac) enter into an agreement with the US Treasury to provide financial support in exchange for Senior Preferred Stock and warrants to purchase common stock of the entities. The actions of the US government were intended to assist Freddie Mac and Fannie Mae in maintaining a positive net worth and meeting their financial obligations. Although the US government provided financial support to such entities, no assurance can be given that it will always do so.

The future for Fannie Mae and Freddie Mac is uncertain. Under a letter agreement between the FHFA (in its role as conservator) and the US Treasury, the FHFA is prohibited from removing its conservatorship of each enterprise until all litigation regarding the conservatorship has ended and each enterprise has retained equity capital levels equal to three percent of their total assets. It is unclear how long it will be before the FHFA will be able to remove its conservatorship of the enterprises under this letter agreement. The FHFA has indicated that the conservatorship of each enterprise will end when the director of FHFA determines that FHFA's plan to restore the enterprise to a safe and solvent condition has been completed. Under amendments to the Enterprise Regulatory Capital Framework ("ERCF"), Fannie Mae and Freddie Mac have published capital disclosures which provide additional information about their capital position and capital requirements on a quarterly basis since the first quarter of 2023 and delivered their first capital plans to FHFA in May 2023. The FHFA finalized amendments to certain provisions of the ERCF in November 2023 that modify various capital requirements for Fannie Mae and Freddie Mac. Should Fannie Mae and Freddie Mac be taken out of conservatorship, it is unclear whether the US Treasury would continue to enforce its rights or perform its obligations under the Senior Preferred Stock Purchase Agreement. It is also unclear how the capital structure of Fannie Mae and Freddie Mac would be constructed post-conservatorship, and what effects, if any, the privatization of Fannie Mae and Freddie Mac will have on their creditworthiness and guarantees of certain mortgage-backed securities. The ERCF requires Fannie Mae and Freddie Mac, upon exit from conservatorship, to maintain higher levels of capital than prior to conservatorship to satisfy their risk-based capital requirements, leverage ratio requirements, and prescribed buffer amounts. Accordingly, should the FHFA take Fannie Mae and Freddie Mac out of conservatorship, there could be an adverse impact on the value of their securities which could cause a fund's investments to lose value. The US Congress and the executive branch, including the US Treasury and the FHFA, continue to evaluate proposals to reduce the US government's role in the mortgage market, including to take Fannie Mae and Freddie Mac out of conservatorship, wind down, restructure, consolidate, or privatize Fannie Mae and Freddie Mac. Should the US government adopt any such proposal, or should the FHFA take Fannie Mae and Freddie Mac out of conservatorship, the value of the fund's investments in securities issued by Fannie Mae or Freddie Mac may be impacted.

US government securities also include separately traded principal and interest components of securities issued or guaranteed by the US Treasury, which are traded independently under the Separate Trading of Registered Interest and Principal of Securities ("STRIPS") program. Under the STRIPS program, the principal and interest components are individually numbered and separately issued by the US Treasury.

On June 3, 2019, under the FHFA's "Single Security Initiative", Fannie Mae and Freddie Mac started issuing uniform mortgage-backed securities ("UMBS"). The Single Security Initiative seeks to align the characteristics of certain Fannie Mae and Freddie Mac mortgage-backed securities and to support the overall liquidity in certain markets. In addition, Freddie Mac has offered investors the opportunity to exchange outstanding legacy mortgage-backed

------

securities for mirror UMBS. The effects that the Single Security Initiative may have on the market and other mortgage-backed securities are uncertain.

Any controversy or ongoing uncertainty regarding the status of negotiations in the US Congress to increase the statutory debt ceiling could increase the risk that the US government may default on payments on certain US government securities, including those held by the funds, which could have a material adverse impact on the funds. The long-term US credit rating has been subject to downgrades by multiple major credit rating agencies since 2011, in part as a result of disagreements within the US government over raising the debt ceiling to repay outstanding obligations, and similar situations in the future could increase volatility in both stock and bond markets, result in higher interest rates, lower prices of US Treasury securities and increase the costs of different kinds of debt. It is at least theoretically possible that under certain scenarios the US government could default on its debt, including US Treasuries. UBS AM cannot predict the effects of these or similar events in the future on the US economy and securities markets or on a fund's portfolio.

**Commercial paper and other short-term obligations.** Each of the funds with "Prime" in its name (the "Prime Funds") may purchase commercial paper, which includes short-term obligations issued by corporations, partnerships, trusts or other entities to finance short-term credit needs. Each of the Prime Funds also may purchase other types of non-convertible debt obligations subject to maturity constraints imposed by the SEC. Descriptions of certain types of short-term obligations are provided below.

**Asset-backed securities.** Each of the Prime Funds may invest in securities that are comprised of financial assets that have been securitized through the use of trusts or special purpose corporations or other entities. Such assets may include motor vehicle and other installment sales contracts, home equity loans, leases of various types of real and personal property and receivables from revolving credit (credit card) agreements or other types of financial assets. Payments or distributions of principal and interest may be guaranteed up to a certain amount and for a certain time period by a letter of credit or pool insurance policy issued by a financial institution unaffiliated with the issuer, or other credit enhancements may be present. See "The funds' investments, related risks and limitations—Credit and liquidity enhancements."

**Variable and floating rate securities and demand instruments.** Each fund may purchase variable and floating rate securities with remaining maturities in excess of 13 months issued by US government agencies or instrumentalities or guaranteed by the US government. In addition, the funds may purchase variable and floating rate securities of municipal and other issuers, including tender option bonds, to the extent otherwise consistent with the funds' investment objectives and policies. The yields on these securities are adjusted in relation to changes in specific rates, such as the prime rate, and different securities may have different adjustment rates. Certain of these obligations carry a demand feature that gives a fund the right to tender them back to a specified party, usually the issuer or a remarketing agent, prior to maturity. A fund's investments in variable and floating rate securities must comply with conditions established by the SEC under which they may be considered to have remaining maturities of 13 months or less. The funds will purchase variable and floating rate securities of non-US government issuers that have remaining maturities of more than 13 months only if the securities are subject to a demand feature exercisable within 13 months or less and otherwise consistent with the funds' investment objectives and policies. See "The funds' investments, related risks and limitations—Credit and liquidity enhancements."

Generally, a fund may exercise demand features (1) upon a default under the terms of the underlying security, (2) to maintain its portfolio in accordance with its investment objective and policies or applicable legal or regulatory requirements or (3) as needed to provide liquidity to the fund in order to meet redemption requests. The ability of a bank or other financial institution to fulfill its obligations under a letter of credit, guarantee or other liquidity arrangement might be affected by possible financial difficulties of its borrowers, adverse interest rate or economic conditions, regulatory limitations or other factors. The interest rate on floating rate or variable rate securities ordinarily is readjusted on the basis of the prime rate of the bank that originated the financing or some other index or published rate, such as the 90-day US

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Treasury bill rate, or is otherwise reset to reflect market rates of interest. Generally, these interest rate adjustments cause the market value of floating rate and variable rate securities to fluctuate less than the market value of fixed rate securities.

**Auction rate and remarketed preferred stock.** The Prime Funds may purchase certain types of auction rate preferred stock ("ARPS") and/or remarketed preferred stock ("RPS") subject to a demand feature. These purchases may include ARPS and RPS issued by closed-end investment companies. ARPS or RPS may be deemed to meet the maturity and quality requirements of money market funds if they are structured to comply with conditions established by the SEC. ARPS and RPS subject to a demand feature, despite their status as equity securities, are economically similar to variable rate debt securities subject to a demand feature. Both ARPS and RPS allow the holder to sell the stock at a liquidation preference value at specified periods, provided that the auction or remarketing is successful. If the auction or remarketing fails, then the holder of certain types of ARPS and RPS may exercise a demand feature and has the right to sell the ARPS or RPS to a third party guarantor or counterparty at a price that can reasonably be expected to approximate its amortized cost; other holders may suffer a partial or complete loss of liquidity. The ability of a bank or other financial institution providing the demand feature to fulfill its obligations might be affected by possible financial difficulties of its borrowers, adverse interest rate or economic conditions, regulatory limitations or other factors.

A fund's investment in ARPS and RPS issued by closed-end funds also is subject to limitations that generally prohibit the fund from investing more than 10% of its assets in securities of other investment companies that are not themselves money market funds. See "The fund's investments, related risks and limitations—Investments in other investment companies."

**Variable amount master demand notes.** Each of the Prime Funds may invest in variable amount master demand notes, which are unsecured redeemable obligations that permit investment of varying amounts at fluctuating interest rates under a direct agreement between a fund and an issuer. The principal amount of these notes may be increased from time to time by the parties (subject to specified maximums) or decreased by a fund or an issuer. These notes are payable on demand (subject to any applicable advance notice provisions) and may or may not be rated.

**Funding agreements and guaranteed investment contracts.** Each of the Prime Funds may invest in funding agreements and guaranteed investment contracts issued by insurance companies which are obligations of the insurance company or one or more segregated asset accounts of the insurance company. Funding agreements permit the investment of varying amounts under a direct agreement between a fund and an insurance company and may provide that the principal amount may be increased from time to time (subject to specified maximums) by agreement of the parties or decreased by either party. A fund expects to invest primarily in funding agreements and guaranteed investment contracts with floating or variable rates. Some funding agreements and guaranteed investment contracts are subject to demand features that permit a fund to tender its interest back to the issuer. To the extent a fund invests in funding agreements and guaranteed investment contracts that either do not have demand features or have demand features that may be exercised more than seven days after the date of acquisition, these investments will be subject to the fund's limitation on investments in illiquid securities. See "The funds' investments, related risks and limitations—Credit and liquidity enhancements" and "—Illiquid securities."

**Investments in financial services.** To the extent a fund's investments are concentrated in the financial services sector, the fund will have correspondingly greater exposure to the risk factors that are characteristic of such investments. In particular, investments in the financial services sector 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.

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**Investing in non-US securities.** Investments by each of the Prime Funds in US dollar-denominated securities of non-US issuers may involve risks that are different from investments in US issuers. These risks may include future unfavorable political and economic developments, possible withholding taxes, seizure of foreign deposits, currency controls, the imposition of international sanctions and other similar measures, interest limitations or other governmental restrictions that might affect the payment of principal or interest on the fund's investments. Additionally, there may be less publicly available information about non-US issuers because they may not be subject to the same regulatory requirements as domestic issuers. A fund's investments in securities issued by US finance subsidiaries of non-US banks may involve similar risks to the extent that a non-US bank is deemed to support its US finance subsidiary. US finance subsidiaries of non-US banks may not be subject to regulation by US state or federal banking regulators.

**Credit and liquidity enhancements.** Each fund may invest in securities that have credit or liquidity enhancements or may purchase these types of enhancements in the secondary market. Such enhancements may be structured as demand features that permit a fund to sell the instrument at designated times and prices. These credit and liquidity enhancements may be backed by letters of credit or other instruments provided by banks or other financial institutions whose credit standing affects the credit quality of the underlying obligation. Changes in the credit quality of these financial institutions could cause losses to a fund and affect its share price. The credit and liquidity enhancements may have conditions that limit the ability of a fund to use them when the fund wishes to do so.

**Illiquid securities.** The term "illiquid securities" means securities that cannot be sold or disposed of in the ordinary course of business within seven calendar days at approximately the amount at which a fund has valued the securities and includes, among other things, repurchase agreements maturing in more than seven days and restricted securities other than those UBS AM has determined are liquid pursuant to guidelines established by a fund's board. A fund may not be able to readily liquidate its investments in illiquid securities and may have to sell other investments if necessary to raise cash to meet its obligations. The lack of a liquid secondary market for illiquid securities may make it more difficult for a fund to assign a value to those securities for purposes of valuing its portfolio and calculating its net asset value.

Restricted securities are not registered under the Securities Act of 1933, as amended ("Securities Act"), and may be sold only in privately negotiated or other exempted transactions or after a registration statement under the Securities Act has become effective. Where registration is required, a fund may be obligated to pay all or part of the registration expenses and a considerable period may elapse between the time of the decision to sell and the time the fund may be permitted to sell a security under an effective registration statement. If, during such a period, adverse market conditions were to develop, a fund might obtain a less favorable price than that which prevailed when it decided to sell.

Not all restricted securities are illiquid. A large institutional market has developed for many US and non-US securities that are not registered under the Securities Act. Institutional investors generally will not seek to sell these instruments to the general public, but instead will often depend either on an efficient institutional market in which such unregistered securities can be readily resold or on an issuer's ability to honor a demand for repayment. Therefore, the fact that there are contractual or legal restrictions on resale to the general public or certain institutions is not dispositive of the liquidity of such investments.

Institutional markets for restricted securities also have developed as a result of Rule 144A under the Securities Act, which establishes a "safe harbor" from the registration requirements of the Securities Act for resales of certain securities to qualified institutional buyers. These markets include automated systems for the trading, clearance and settlement of unregistered securities of US and non-US issuers, such as the PORTAL System sponsored by the Financial Industry Regulatory Authority (previously, the National Association of Securities Dealers, Inc. ("FINRA")). An insufficient number of qualified institutional buyers interested in purchasing Rule 144A-eligible restricted securities held by a fund, however, could affect adversely the marketability of such portfolio securities, and the fund might be unable to dispose of them promptly or at favorable prices.

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The board has delegated the function of making day-to-day determinations of liquidity to UBS AM pursuant to guidelines approved by the board. UBS AM takes into account a number of factors in reaching liquidity decisions, which may include (1) the frequency of trades for the security, (2) the number of dealers that make quotes, or are expected to make quotes, for the security, (3) the nature of the security and how trading is effected (*e.g.*, the time needed to sell the security, how bids are solicited and the mechanics of transfer) and (4) the existence of demand features or similar liquidity enhancements. UBS AM monitors the liquidity of restricted securities in each fund's portfolio and reports periodically on such decisions to the board.

UBS AM also monitors each fund's overall holdings of illiquid securities. If a fund's holdings of illiquid securities exceed its limitation on investments in illiquid securities for any reason (such as a particular security becoming illiquid, changes in the relative market values of portfolio securities or shareholder redemptions), UBS AM will consider what action would be in the best interests of the fund and its shareholders. Such action may include engaging in an orderly disposition of securities to reduce the fund's holdings of illiquid securities. However, a fund is not required to dispose of illiquid securities under these circumstances.

**Repurchase agreements.** Each fund may enter into repurchase agreements. Repurchase agreements are transactions in which a fund purchases securities or other obligations from a bank or securities dealer (or its affiliate) and simultaneously commits to resell them to the counterparty at an agreed-upon date or upon demand and at a price reflecting a market rate of interest unrelated to any coupon rate or maturity of the purchased obligations. Securities or other obligations subject to repurchase agreements may have maturities in excess of 13 months. A fund maintains custody of the underlying obligations prior to their repurchase, either through its regular custodian or through a special tri-party custodian or sub-custodian that maintains separate accounts for both a fund and its counterparty. Thus, the obligation of the counterparty to pay the repurchase price on the date agreed to or upon demand is, in effect, secured by such obligations. A fund may utilize a put feature to limit the maturity of repurchase agreements it enters into in accordance with Rule 2a-7 under the Investment Company Act.

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 the collateral is at least equal to the repurchase price plus any agreed-upon additional amount. The difference between the total amount to be received upon repurchase of the obligations and the price that was paid by a fund upon acquisition is accrued as interest and included in its net investment income. 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. Moreover, repurchase agreements secured by obligations that are not eligible for direct investment under Rule 2a-7 under the Investment Company Act or a fund's investment strategies and limitations may require the fund to promptly dispose of such collateral if the seller or guarantor becomes insolvent. If the seller or guarantor becomes insolvent, a fund may suffer delays, costs and possible losses in connection with the disposition of collateral. Such an insolvency may result in a loss to the extent that the value of the purchased securities or other assets decreases during the delay or that value has otherwise not been maintained at an amount equal to the repurchase price.

In December 2023, the SEC adopted rule amendments providing that any covered clearing agency ("CCA") for US Treasury securities require its direct participants (which generally would be a bank or broker-dealer) to submit for clearance and settlement all eligible secondary market transactions in US Treasury securities to which the direct participant is a counterparty. The clearing mandate includes in its scope all repurchase or reverse repurchase agreements of such direct participants collateralized by US Treasury securities (collectively, "Treasury repo transactions") of a type accepted for clearing by a registered CCA, including both bilateral Treasury repo transactions and triparty Treasury repo transactions where a bank agent provides custody, collateral management and settlement services.

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The Treasury repo transactions of the funds with any direct participants of a CCA will be subject to the mandatory clearing requirement. Compliance with the clearing mandate for Treasury repo transactions will be required as of June 30, 2027. The funds will be required to clear all or substantially all of their Treasury repo transactions as of the compliance date. There are currently substantial regulatory and operational uncertainties associated with the implementation of these requirements which may affect the cost, terms and/or availability of cleared repo transactions.

**Reverse repurchase agreements.** Reverse repurchase agreements involve the sale of securities held by the fund subject to its agreement to repurchase the securities at an agreed-upon date or upon demand and at a price reflecting a market rate of interest. Reverse repurchase agreements are subject to the fund's limitation on borrowings and may be entered into only with banks or securities dealers or their affiliates. Reverse repurchase agreements involve the risk that the buyer of the securities sold by the fund might be unable to deliver them when the fund seeks to repurchase. If the buyer of securities under a reverse repurchase agreement files for bankruptcy or becomes insolvent, the buyer or trustee or receiver may receive an extension of time to determine whether to enforce the fund's obligation to repurchase the securities, and the fund's use of the proceeds of the reverse repurchase agreement may effectively be restricted pending such decision.

**Counterparty risk.** A fund may be exposed to the risk of financial failure or insolvency of another party. To help lessen those risks, UBS AM and/or its affiliates, subject to the supervision of the board, monitors and evaluates the creditworthiness of the parties with which a fund does business.

**Operations risk.** Each fund is subject to the risk that it may not be able to complete a transaction in the manner or at the time desired or other potential operational issues because of difficulties with the settlement process or other functions related to the processing of securities transactions. Such risks may arise from factors such as processing errors, human errors, inadequate or failed internal or external processes and controls, failures in systems and technology, documentation issues, changes in personnel and errors caused by third-party service providers.

**Risk associated with the fund holding cash.** UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund will generally hold a portion of its assets in cash for operational purposes. Cash positions may hurt performance and may subject a fund to additional risks and costs, such as increased exposure to the custodian bank holding the assets and fees imposed for large cash balances. In addition, interest income received by the fund from cash held at the custodian would not qualify for the state and local income tax exemption applicable to certain dividends paid by certain funds that are derived from interest income with respect to US government securities.

**When-issued and delayed delivery securities.** Each fund may purchase securities on a "when-issued" basis or may purchase or sell securities for delayed delivery to or by the fund later than the normal settlement date at a stated price and yield. A fund generally would not pay for such securities or start earning interest on them until they are received. However, when a fund undertakes a when-issued or delayed delivery obligation, it immediately assumes the risks of ownership, including the risks of price fluctuation. Failure of the issuer to deliver a security purchased by a fund on a when-issued or delayed delivery basis may result in the fund's incurring a loss or missing an opportunity to make an alternative investment.

A security purchased on a when-issued or delayed delivery basis is recorded as an asset on the commitment date and is subject to changes in market value, generally based upon changes in the level of interest rates. Thus, fluctuation in the value of the security from the time of the commitment date will affect a fund's net asset value. When a fund commits to purchase securities on a when-issued or delayed delivery basis, it will designate cash or other liquid assets on the books of its custodian, marked to market daily, in an amount at least equal to its obligations under the commitment. A fund's when-issued and delayed delivery purchase commitments could cause its net asset value per share to be more volatile.

A fund may sell the right to acquire the security prior to delivery if UBS AM deems it advantageous to do so, which may result in a gain or loss to the fund.

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The SEC adopted a rule ("Rule 18f-4") related to the use of derivatives, reverse repurchase agreements and certain other transactions by registered investment companies. A money market fund cannot rely on Rule 18f-4 to use such instruments, with a limited exception for investments in certain when-issued, forward-settling and non-standard settlement cycle securities transactions. Under Rule 18f-4, a money market fund, such as the fund, is only permitted to invest in a security on a when-issued or forward-settling basis, or with a non-standard settlement cycle, and the transaction will be deemed not to involve a senior security (as defined under Section 18(g) of the Investment Company Act), provided that, (i) the fund intends to physically settle the transaction and (ii) the transaction will settle within 35 days of its trade date. These requirements may limit the ability of a fund to invest in securities on a when-issued or forward-settling basis, or with a non-standard settlement cycle, as part of its investment strategies.

**Investments in other investment companies.** Each fund may invest in securities of other investment companies subject to limitations imposed by the Investment Company Act. Among other things, these limitations generally restrict a fund's aggregate investments in other investment companies that are not themselves money market funds to no more than 10% of its total assets, subject to a number of exceptions under SEC rules, including Rule 12d1-4. The feeder funds intend to rely on Section 12(d)(1)(E) of the Investment Company Act, which allows a fund to invest substantially all of its assets in the securities of other investment companies (*i.e.*, the master fund) without regard to the 10% limitation.

**Lending of portfolio securities.** Each fund is authorized to lend its portfolio securities to broker-dealers or institutional investors that UBS AM deems qualified. Lending securities enables a fund to earn additional income, but could result in a loss or delay in recovering these securities. The borrower of a fund's portfolio securities must maintain acceptable collateral with the fund's custodian (or a sub-custodian or a special "tri-party" custodian) in an amount, marked to market daily, at least equal to the market value of the securities loaned, plus accrued interest and dividends. Acceptable collateral is limited to cash and US government securities. Each fund may reinvest any cash collateral in money market investments or other short-term liquid investments, including other investment companies. In determining whether to lend securities to a particular broker-dealer or institutional investor, UBS AM or a lending agent subject to UBS AM direction and oversight will consider, and during the period of the loan will monitor, all relevant facts and circumstances, including the creditworthiness of the borrower. Each fund will retain authority to terminate any of its loans at any time. Each fund may pay reasonable fees in connection with a loan and may pay the borrower or placing broker a negotiated portion of the interest earned on the reinvestment of cash held as collateral. Each fund will receive amounts equivalent to any interest, dividends or other distributions on the securities loaned. Each fund will seek to retain record ownership of loaned securities to exercise beneficial rights, such as voting and subscription rights, when retaining such rights is considered to be in the fund's interest and operationally reasonably practicable.

State Street Bank and Trust Company ("State Street") has been approved to serve as lending agent and receives fees for such services. Additionally, State Street has been approved to engage a third party bank as a special "tri-party" custodian for securities lending arrangements.

**Types of municipal securities.** The Prime Funds may invest in a variety of municipal securities, as described below.

**Municipal bonds.** Municipal bonds are debt obligations that are issued by states, municipalities, public authorities or other issuers and that pay interest that is exempt from federal income tax in the opinion of issuer's counsel. The two principal classifications of municipal bonds are "general obligation" and "revenue" bonds. General obligation bonds are secured by the issuer's pledge of its full faith, credit and taxing power for the payment of principal and interest. Revenue bonds are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue source such as from the user of the facility being financed. The term "municipal bonds" also includes "moral obligation" issues, which are normally issued by special purpose authorities. In the case of such issues, an express or implied "moral obligation" of a related governmental unit is pledged to the payment of the debt service but is usually subject to annual budget appropriations. Custodial receipts that represent an ownership interest in one or more municipal bonds also are considered to be municipal bonds. Various types of municipal bonds are described in the following sections.

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Municipal securities and issuers of municipal securities may be more susceptible to downgrade, default, and bankruptcy during periods of economic stress. Factors contributing to the economic stress may include: lower property tax collections as a result of lower home values, lower sales tax revenue as a result of reduced consumer spending, lower income tax revenue as a result of higher unemployment rates, and budgetary constraints of local, state and federal governments upon which issuers of municipal securities may be relying for funding. In addition, as certain municipal securities may be secured or guaranteed by banks and other institutions, the risk to a fund could increase if the banking, insurance or other parts of the financial sector suffer an economic downturn and/or the credit ratings of the institutions issuing the guarantee are downgraded or are at risk of being downgraded by a national rating organization. Such a downward revision or risk of being downgraded may have an adverse effect on the market prices of the securities and thus the value of a fund's investment. Further, a state, municipality, public authority or other issuers of municipal securities may file for bankruptcy, which may significantly affect the value of the securities issued by such issuers and therefore the value of a fund's investment.

Municipal securities are also subject to the risk that the perceived increase in the likelihood of default or downgrade among municipal issuers as a result of market conditions could result in increased illiquidity, volatility and credit risk. In addition, certain municipal issuers may be unable to access the market to sell securities or, if able to access the market, may be forced to issue securities at much higher rates. Should these municipal issuers fail to sell bonds when and at the rates projected, these entities could experience significantly increased costs and a weakened overall cash position in the current fiscal year and beyond. These events could also result in decreased investment opportunities for a fund and lower investment performance.

**Municipal lease obligations.** Municipal bonds include municipal lease obligations, such as leases, installment purchase contracts and conditional sales contracts and certificates of participation therein. Municipal lease obligations are issued by state and local governments and authorities to purchase land or various types of equipment or facilities and may be subject to annual budget appropriations. Funds generally invest in municipal lease obligations through certificates of participation.

Although municipal lease obligations do not constitute general obligations of the municipality for which the municipality's taxing power is pledged, they ordinarily are backed by the municipality's covenant to budget for, appropriate and make the payments due under the lease obligation. The leases underlying certain municipal lease obligations, however, provide that lease payments are subject to partial or full abatement if, because of material damage or destruction of the leased property, there is substantial interference with the lessee's use or occupancy of such property. This "abatement risk" may be reduced by the existence of insurance covering the leased property, the maintenance by the lessee of reserve funds or the provision of credit enhancements such as letters of credit.

Certain municipal lease obligations contain "non-appropriation" clauses which provide that the municipality has no obligation to make lease or installment purchase payments in future years unless money is appropriated for such purpose on a yearly basis. Some municipal lease obligations of this type are insured as to timely payment of principal and interest, even in the event of a failure by the municipality to appropriate sufficient funds to make payments under the lease. Insurance does not guarantee the price of the municipal lease obligations. The credit rating of an insured municipal lease obligation reflects the credit rating of the insurer, based on its claims paying ability. The insurance feature is intended to reduce financial risk, but the cost of such insurance and the restrictions on investments imposed by the guidelines in the municipal insurance policy will result in a reduction in the yield on the insured municipal lease obligations purchased by a fund. However, in the case of an uninsured municipal lease obligation, a fund's ability to recover under the lease in the event of a non-appropriation or default will be limited solely to the repossession of leased property without recourse to the general credit of the lessee, and disposition of the property in the event of foreclosure might prove difficult.

**Industrial development bonds ("IDBs") and private activity bonds ("PABs").** IDBs and PABs are issued by or on behalf of public authorities to finance various privately operated facilities, such as airport or pollution control

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facilities. These obligations are considered municipal bonds if the interest paid thereon is exempt from federal income tax in the opinion of the bond issuer's counsel. IDBs and PABs are in most cases revenue bonds and thus are not payable from the unrestricted revenues of the issuer. The credit quality of IDBs and PABs is usually directly related to the credit standing of the user of the facilities being financed. IDBs issued after August 15, 1986 generally are considered PABs, and to the extent a fund invests in PABs, shareholders generally will be required to treat a portion of their exempt-interest dividends from that fund as a "Tax Preference Item." See "Taxes" below. Each fund investing in municipal securities may invest more than 25% of its assets in IDBs and PABs.

**Participation interests.** Participation interests are interests in municipal bonds, including IDBs, PABs and floating and variable rate obligations, that are owned by financial institutions. These interests carry a demand feature permitting the holder to tender them back to the financial institution, which demand feature generally is backed by an irrevocable letter of credit or guarantee of the financial institution. The credit standing of such financial institution affects the credit quality of the participation interests.

A participation interest gives a fund an undivided interest in a municipal bond owned by a financial institution. The fund has the right to sell the instrument back to the financial institution. As discussed above under "The funds' investments, related risks and limitations—credit and liquidity enhancements," to the extent that payment of an obligation is backed by a letter of credit, guarantee or liquidity support arrangement from a financial institution, that payment may be subject to the financial institution's ability to satisfy that commitment. UBS AM will monitor the pricing, quality and liquidity of the participation interests held by a fund, and the credit standing of financial institutions issuing letters of credit or guarantees supporting those participation interests on the basis of published financial information, reports of rating services and financial institution analytical services.

**Put bonds.** A put bond is a municipal bond that gives the holder the unconditional right to sell the bond back to the issuer or a third party at a specified price and exercise date, which is typically well in advance of the bond's maturity date. The obligation to purchase the bond on the exercise date may be supported by a letter of credit or other credit support arrangement from a bank, insurance company or other financial institution, the credit standing of which affects the credit quality of the obligation.

If a fund holds a bond subject to a "one time only" put, the fund ordinarily will either sell the bond or put the bond, depending upon the more favorable price. If a bond has a series of puts after the first put, it will be held as long as, in the judgment of UBS AM, it is in the fund's best interest to do so. There is no assurance that the issuer of a put bond acquired by a fund will be able to repurchase the bond on the exercise date, if the fund chooses to exercise its right to put the bond back to the issuer or to a third party.

**Tender option bonds.** Tender option bonds are long-term municipal securities (or interests therein) sold by a bank, other financial institution or special purpose entity subject to a demand feature that gives the purchaser the right to sell them to the bank or other financial institution at par plus accrued interest at designated times (the "tender option"). Each fund investing in municipal securities may invest in such securities with tender options that may be exercisable at intervals ranging from daily to 397 days, and the interest rate on such securities is typically reset at the end of the applicable interval in an attempt to cause the bonds to have a market value that approximates their par value, plus accrued interest. The tender option may not be exercisable in the event of a default on, or significant downgrading of, the underlying municipal securities, and may be subject to other conditions. Therefore, a fund's ability to exercise the tender option will be affected by the credit standing of both the bank or other financial institution involved and the issuer of the underlying securities or its insurer (if any). If a fund invests in tender option bonds, the financial statements, financial highlights and other materials containing financial information of that fund will properly reflect these transactions, and the fund's independent accountants will concur with the accounting treatment being applied to the fund's transactions.

**Tax-exempt commercial paper and short-term municipal notes.** Municipal bonds include tax-exempt commercial paper and short-term municipal notes, such as tax anticipation notes, bond anticipation notes, revenue

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anticipation notes and other forms of short-term securities. Such notes are issued with a short-term maturity in anticipation of the receipt of tax funds, the proceeds of bond placements and other revenues. Investments in municipal bonds may be subject to additional risks, such as the failure of the issuer to make payments because of political issues or adverse determinations as to taxability that may negatively impact value.

**Mortgage subsidy bonds.** Funds investing in municipal securities also may purchase mortgage subsidy bonds with a remaining maturity of less than 13 months that are issued to subsidize mortgages on single family homes and "moral obligation" bonds with a remaining maturity of less than 13 months that are normally issued by special purpose public authorities. In some cases the repayment of these bonds depends upon annual legislative appropriations; in other cases repayment is a legal obligation of the issuer, and if the issuer is unable to meet its obligations, repayment becomes a moral commitment of a related governmental unit (subject, however, to such appropriations).

**Stand-by commitments.** Funds investing in municipal securities may acquire stand-by commitments under unusual market conditions to facilitate portfolio liquidity. Pursuant to a stand-by commitment, a municipal bond dealer agrees to purchase the securities that are the subject of the commitment at an amount equal to (1) the acquisition cost (excluding any accrued interest paid on acquisition), less any amortized market premium and plus any accrued market or original issue discount, plus (2) all interest accrued on the securities since the last interest payment date or the date the securities were purchased, whichever is later.

A fund will enter into stand-by commitments only with those banks or other dealers that, in the opinion of UBS AM, present minimal credit risk. A fund's right to exercise stand-by commitments will be unconditional and unqualified. Stand-by commitments will not be transferable by a fund, although a fund may sell the underlying securities to a third party at any time. A fund may pay for stand-by commitments either separately in cash or by paying a higher price for the securities that are acquired subject to such a commitment (thus reducing the yield to maturity otherwise available for the same securities). The acquisition of a stand-by commitment will not ordinarily affect the valuation or maturity of the underlying municipal securities. Stand-by commitments acquired by a fund will be valued at zero in determining net asset value. Whether a fund paid directly or indirectly for a stand-by commitment, its cost will be treated as unrealized depreciation and will be amortized over the period the fund holds the commitment.

**Master-feeder structure.** Unlike other funds which directly acquire and manage their own portfolio securities, each fund seeks to achieve its objective by investing substantially all of its assets in a corresponding master fund, a separate registered open-end investment company with the same objective as the fund.

Therefore, a shareholder's interest in the master fund's securities is indirect. In addition to selling beneficial interests to the funds, a master fund may sell beneficial interests to other mutual funds and other investors. Such investors will invest in the master fund on similar terms and conditions and will pay a proportionate share of the master fund's expenses. However, the other investors investing in the master fund may have different operating expenses or characteristics. Therefore, shareholders should be aware that these differences might result in differences in returns experienced by investors in different mutual funds that invest in the corresponding master funds. Such differences in return are also present in other mutual fund structures. Information concerning other holders of interest in the master funds is available by contacting UBS AM at 1-888-547 FUND.

The master-feeder structure is relatively complex, so shareholders should carefully consider this investment approach.

Small funds investing in a corresponding master fund may be materially affected by the actions of larger investors invested in the master fund. Investors with a greater pro rata ownership in the master fund could have effective voting control of the operation of the master fund. Whenever the investors in the master fund are requested to vote on matters relating to a master fund, the master fund will, except as permitted by the SEC, submit matters to all of its feeder funds and other investors for a vote. A feeder fund asked to vote on matters pertaining to its corresponding master fund will either hold a shareholder meeting and vote in accordance with shareholder instructions, or otherwise act in accordance with applicable law.

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Certain changes in a master fund's objectives, policies or restrictions may require a feeder fund to withdraw its interest in the master fund. Any such withdrawal could result in a distribution "in kind" of portfolio securities (as opposed to a cash distribution from the master fund). If securities are distributed, a fund could incur tax and other charges in converting the securities to cash. In addition, the distribution in kind may result in a less diversified portfolio of investments or adversely affect the liquidity of a fund. Notwithstanding the above, there are some other means for meeting redemption requests, such as borrowing.

A fund may withdraw its investment in a corresponding master fund at any time, if the board determines that it is in the best interests of the shareholders of the fund to do so. Upon any such withdrawal, the board would consider what action might be taken, including the investment of all the assets of the fund in another pooled investment entity having the same objective as the fund or the retention of an investment advisor to manage the fund's assets in accordance with the investment policies described elsewhere herein.

**Cybersecurity/Technology risk.** As the use of technology has become more prevalent in the course of business, a fund, like other business organizations, has become more susceptible to operational, information security and related risks through breaches in cybersecurity. In general, cybersecurity failures or breaches of a fund or its service providers or the issuers of securities in which a 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 a 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 a 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 a 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.

While UBS AM has established business continuity plans in the event of, and risk management systems to prevent, such cybersecurity breaches, there are inherent limitations in such plans and systems including the possibility that certain risks have not been identified. Furthermore, UBS AM does not directly control the cybersecurity plans and systems put in place by the funds' other service providers or any other third parties whose operations may affect a fund or its shareholders. A fund and its shareholders could be negatively impacted as a result.

Although the UBS Select 100% US Treasury Institutional Fund does not currently employ blockchain technology in connection with Token-Enabled Shares, financial intermediaries through whom shareholders purchase and redeem Token-Enabled Shares intend to employ blockchain technology to maintain a record or a mirror record of share ownership for their customers. A blockchain is a type of distributed ledger technology that records transactions between parties in a verifiable and append-only manner using cryptography. Transactions on the blockchain are verified and authenticated by computers on the network. The process of authenticating a transaction before it is recorded seeks to ensure that only valid and authorized transactions are permanently recorded on the blockchain in collections of transactions called "blocks." Blockchain networks are based upon software source code that establishes and governs their respective cryptographic systems for verifying transactions. Complex information technology and communications systems, such as blockchain networks, are subject to a number of different threats or risks (including operational, information security, cyber-attacks and related risks) that could adversely affect the fund, its shareholders and financial intermediaries through whom shareholders purchase and redeem Token-Enabled Shares of the fund. The use of distributed ledger technology, including blockchain, is relatively new and still evolving. The fund, its transfer agent, advisor, distributor and their affiliates will not be responsible for any loss in connection with the use of blockchain technology by a financial intermediary subject to applicable law. Shareholders should contact your financial intermediary about whether or how it uses blockchain technology and the associated risks.

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**Market risk.** Market risks, including political, regulatory, market, economic and social developments, and developments that impact specific economic sectors, industries or segments of the market, can affect the value and liquidity of the funds' investments. In addition, turbulence in financial markets and reduced liquidity in equity and/or fixed-income markets may negatively affect the funds. 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 a 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.

To the extent a fund is overweight in certain countries, regions, companies, industries or market sectors, such positions will increase the risk of loss from adverse developments affecting those countries, regions, companies, industries or sectors.

**Low or negative interest rates.** In a low or negative interest rate environment, debt instruments may trade at negative yields, which means the purchaser of the instrument may receive at maturity less than the total amount invested. In addition, in a negative interest rate environment, if a bank charges negative interest, instead of receiving interest on deposits, a depositor must pay the bank fees to keep money with the bank. To the extent a fund holds a negatively-yielding debt instrument or has a bank deposit with a negative interest rate, the funds would generate a negative return on that investment.

In the past, certain European countries and Japan have pursued negative interest rate policies, and there is the possibility that negative interest rate policies might be pursued in the United States at some point in the future. In a low or negative interest rate environment, some investors may seek to reallocate assets to other income-producing assets, such as investment-grade and higher-yield debt instruments, or equity investments that pay a dividend, absent other market risks that may make such alternative investments unattractive. This increased demand for higher yielding assets may cause the price of such instruments to rise while triggering a corresponding decrease in yield over time, thus reducing the value of such alternative investments. In addition, a move to higher yielding investments may cause investors, including a fund (to the extent permitted by its investment objective and strategies), to seek fixed-income investments with longer maturities and/or potentially reduced credit quality in order to seek the desired level of yield. These considerations may limit the funds' ability to locate fixed-income instruments containing the desired risk/return profile.

For funds that seek to maintain a stable $1.00 share price, a low or negative interest rate environment could impact such funds' ability to do so. If such a fund has a negative gross yield as a result of negative interest rates, it may reduce the number of shares outstanding on a pro rata basis through reverse stock splits, negative dividends or other mechanisms to seek to maintain a stable $1.00 price per share, to the extent permissible by applicable law and its organizational documents. The use of such measures is also subject to certain determinations by the fund's board and disclosure requirements, and may have tax implications for the fund and its shareholders. Alternatively, such funds may discontinue using the amortized cost method of valuation to maintain a stable $1.00 price per share and establish a fluctuating net asset value per share rounded to four decimal places by using available market quotations or equivalents. In addition, for funds that have a fluctuating net asset value per share rounded to four decimal places using market-based pricing, a low or negative interest rate environment could increase fluctuation or volatility of the net asset value per share for such funds.

Investment limitations of the funds

**Fundamental investment limitations.** The following investment limitations, which apply to the funds and their corresponding master funds, cannot be changed with respect to a fund or master fund without the affirmative vote

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of the lesser of (a) more than 50% of the outstanding shares of the fund or (b) 67% or more of the shares present at a shareholders' meeting if more than 50% of the outstanding shares are represented at the meeting in person or by proxy. If a percentage restriction is adhered to at the time of an investment or transaction, a later increase or decrease in percentage resulting from changing values of portfolio securities or amount of total assets will not be considered a violation of any of the following limitations. With regard to the borrowings limitation in fundamental limitation (2), the fund will comply with the applicable restrictions of Section 18 of the Investment Company Act.

Each fund will not:

(1) Purchase securities of any one issuer if, as a result, more than 5% of the fund's total assets would be invested in
securities of that issuer or the fund would own or hold more than 10% of the outstanding voting securities of that issuer, except that up to 25% of the fund's total assets may be invested without regard to this limitation, and except that this
limitation does not apply to securities issued or guaranteed by the US government, its agencies and instrumentalities or to securities issued by other investment companies.

The following interpretations apply to, but are not a part of, this fundamental restriction: (a) mortgage-and asset-backed securities will not be considered to have been issued by the same issuer by reason of the securities having the same sponsor, and mortgage-and asset-backed securities issued by a finance or other special purpose subsidiary that are not guaranteed by the parent company will be considered to be issued by a separate issuer from the parent company, and (b) consistent with SEC and SEC staff guidance, the funds may invest up to 10% of their total assets in securities that are subject to demand features or guarantees issued by a single institution.

(2) Issue senior securities or borrow money, except as permitted under the Investment Company Act and then not in excess of
33<sup>1</sup>⁄<sub>3</sub>% of the fund's total assets (including the amount of the senior securities issued but reduced by any liabilities not constituting senior securities) at
the time of the issuance or borrowing, except that the fund may borrow up to an additional 5% of its total assets (not including the amount borrowed) for temporary or emergency purposes.

(3) Make loans, except through loans of portfolio securities or through repurchase agreements, provided that for purposes of
this restriction, the acquisition of bonds, debentures, other debt securities or instruments, or participations or other interests therein and investments in government obligations, commercial paper, certificates of deposit, bankers'
acceptances or similar instruments will not be considered the making of a loan.

The following interpretation applies to, but is not a part of, this fundamental restriction: Investments in master notes, funding agreements and similar instruments will not be considered to be the making of a loan.

(4) Engage in the business of underwriting securities of other issuers, except to the extent that the fund might be
considered an underwriter under the federal securities laws in connection with its disposition of portfolio securities.

(5) Purchase or sell real estate, except that investments in securities of issuers that invest in real estate and investments
in mortgage-backed securities, mortgage participations or other instruments supported by interests in real estate are not subject to this limitation, and except that the fund may exercise rights under agreements relating to such securities,
including the right to enforce security interests and to hold real estate acquired by reason of such enforcement until that real estate can be liquidated in an orderly manner.

(6) Purchase or sell physical commodities unless acquired as a result of owning securities or other instruments, but the fund
may purchase, sell or enter into financial options and futures, forward and spot currency contracts, swap transactions and other financial contracts or derivative instruments.

Each fund, other than UBS Prime Reserves Fund and UBS Prime Preferred Fund, will not:

(7) Purchase any security if, as a result of that purchase, 25% or more of the fund's total assets would be invested in
securities of issuers having their principal business activities in the same industry, except that this limitation does

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not apply to securities issued or guaranteed by the US government, its agencies or instrumentalities or to municipal securities or to certificates of deposit and bankers' acceptances of domestic branches of US banks.

The following interpretations apply to, but are not a part of, this fundamental restriction: (a) US banking (including US finance subsidiaries of non-US banks) and non-US banking will be considered to be different industries; (b) asset-backed securities will be grouped in industries based upon their underlying assets and not treated as constituting a single, separate industry; (c) tax-exempt securities backed only by the assets and revenues of a non-government user will be considered to be subject to this industry concentration limitation; and (d) taxable municipal securities will not be considered municipal securities for purposes of this industry concentration limitation.

Each of UBS Prime Reserves Fund and UBS Prime Preferred Fund will, under normal circumstances:

(8) Invest more than 25% of its total assets (measured at the time of purchase) in the financial services group of
industries. Each fund may not concentrate its investments in any other industry outside of financial services. That is, each fund may not invest more than 25% of its total assets (measured at the time of purchase) in securities of issuers whose
principal business activities are in the same industry outside of financial services, except that this limit does not apply to (a) securities issued or guaranteed by the US government, (b) any of its agencies or instrumentalities and
(c) repurchase agreements secured by such obligations.

The following interpretations apply to, but are not a part of, this fundamental restriction: the financial services group of industries is deemed to include industries within the financial services sector, including US banking, non-US banking, broker-dealers, insurance companies, finance companies (*e.g.*, automobile finance), and related asset-backed securities. Asset-backed securities will be grouped in industries based upon their underlying assets and not treated as constituting a single, separate industry. UBS AM may analyze the characteristics of a particular issuer and security and assign an industry classification consistent with those characteristics in the event that either a third-party classification provider used by UBS AM or another fund service provider does not assign a classification or assigns a classification inconsistent with that believed appropriate by UBS AM based on its analysis of the economic characteristics of the issuer.

**Non-fundamental investment limitations.** The following investment restrictions, which apply to the funds and their corresponding master funds, are non-fundamental and may be changed by the vote of the board without shareholder approval. If a percentage restriction is adhered to at the time of an investment or transaction, a later increase or decrease in percentage resulting from changing values of portfolio securities or amount of total assets will not be considered a violation of any of the following limitations.

Each fund will not:

(1) purchase securities on margin, except for short-term credit necessary for clearance of portfolio transactions.

(2) purchase portfolio securities while borrowings in excess of 5% of its total assets are outstanding.

**Note regarding other investment limitations.** In addition to the fund's investment policies and restrictions, UBS AM may adopt certain additional internal investment criteria which may further restrict the fund's investments. As of the date of this SAI, UBS AM policies prohibit investments by a fund in businesses involved in:

• Controversial weapons, which cover:

–cluster munitions

–anti-personnel mines

–chemical weapons

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–biological weapons

–nuclear weapons produced in breach of the Treaty on the Non-Proliferation of Nuclear Weapons

• Depleted Uranium manufacturing

• Thermal coal extraction and oil sands production/mining (20% revenue threshold at acquisition)

UBS AM may modify this list of prohibited investments, at any time, without shareholder approval or notice.

Because the above policy may cause the funds to exclude certain investments for nonfinancial reasons, the funds may forego some market opportunities available to funds that do not have such a policy.

Disclosure of portfolio holdings

The funds will hold beneficial interests in the master funds for so long as they continue to participate in the master-feeder arrangement. During that time, the portfolio holdings disclosure policies and procedures of the funds will apply to the master funds, which hold portfolio securities directly.

**Policies and procedures generally.** UBS AM and each fund's board have adopted portfolio holdings disclosure policies and procedures to govern the disclosure of the portfolio holdings of a fund. UBS AM and each fund's chief compliance officer also considered actual and potential material conflicts that could arise in such circumstances between the interests of fund shareholders, on the one hand, and those of a fund's investment advisor, distributor, or any affiliated person of a fund, its investment advisor, or its distributor, on the other. Each fund's disclosure policy with respect to the release of portfolio holdings information is to release only such information consistent with applicable legal requirements and the fiduciary duties owed to shareholders. Subject to the limited exceptions described below, each fund's portfolio holdings will not be made available to anyone outside of UBS AM unless and until the information has been made available to all shareholders or the general public in a manner consistent with the spirit and terms of this policy. A description of the type and frequency of portfolio holdings that are disclosed to the public also is contained in the funds' prospectuses.

After giving due consideration to such matters and after the exercise of their fiduciary duties and reasonable business judgment, UBS AM and each fund's board determined that each fund has a legitimate business purpose for disclosing portfolio holdings to certain persons/entities and that the policies and procedures are reasonably designed to ensure that disclosure of portfolio holdings and information about portfolio holdings is in the best interests of fund shareholders and appropriately address the potential for material conflicts of interest.

UBS AM's procedures require that the UBS AM Legal and/or Compliance Departments address any material conflicts of interest regarding a disclosure of portfolio holdings and determine whether a disclosure of a fund's portfolio holdings is for a legitimate business purpose and in the best interests of the fund's shareholders prior to the Treasurer, Assistant Treasurer, Secretary or Assistant Secretary of each fund or the UBS AM Legal and/or Compliance Departments authorizing the disclosure of portfolio holdings. The UBS AM Legal and/or Compliance Departments will periodically review how each fund's portfolio holdings are being disclosed to and used by, if at all, service providers, UBS AM affiliates and certain fiduciaries, and broker-dealers to ensure that such disclosure and use is for legitimate fund business reasons and consistent with the best interests of the fund's shareholders.

**Board oversight.** Each fund's board exercises continuing oversight of the disclosure of fund portfolio holdings by (i) overseeing the implementation and enforcement by the fund's chief compliance officer of the portfolio holdings disclosure policies and procedures, and the fund's policies and procedures regarding the misuse of inside information; (ii) considering reports and recommendations by the chief compliance officer concerning any material compliance matters (as defined in Rule 38a-1 under the Investment Company Act and Rule 206(4)-7 under the Investment Advisers Act of 1940 ("Advisers Act")) that may arise in connection with any policies governing portfolio holdings, and (iii) considering whether to approve or ratify any amendment to any policies governing portfolio holdings. UBS AM and each fund's board reserve the right to amend a fund's policies and procedures regarding the disclosure of portfolio holdings at any time and from time to time subject to the approval of each fund's board.

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**Complete portfolio holdings—disclosure to service providers subject to confidentiality and trading restrictions.** UBS AM, for legitimate business purposes, may disclose a fund's complete portfolio holdings at times it deems necessary and appropriate to rating and ranking organizations, financial printers, proxy voting service providers, pricing information vendors, third-parties that deliver analytical, statistical or consulting services, custodians or a redeeming party's custodian or transfer agent as necessary in connection with redemptions in kind, and other third parties that provide services (collectively, "Service Providers") to UBS AM and/or a fund.

Disclosure of complete portfolio holdings to a Service Provider is conditioned on the Service Provider being subject to a duty of confidentiality, including a duty not to trade on the basis of any material nonpublic information pursuant to the terms of the service agreement between the Service Provider and a fund or UBS AM, or the terms of the confidentiality agreement. The frequency with which complete portfolio holdings may be disclosed to a Service Provider, and the length of lag, if any, between the date of information and the date on which the information is disclosed to the Service Provider, is determined based on the facts and circumstances, including, without limitation, the nature of the portfolio holdings information to be disclosed, the risk of harm to a fund and its shareholders, and the legitimate business purposes served by such disclosure. Disclosure of complete portfolio holdings to a Service Provider must be authorized by a Trust officer or the General Counsel, Deputy General Counsel or an Associate General Counsel within the Legal and Compliance Departments of UBS AM.

**Complete portfolio holdings—disclosure to UBS AM affiliates and certain fiduciaries subject to confidentiality and trading restrictions.** A fund's complete portfolio holdings may be disclosed between and among the following persons (collectively, "Affiliates and Fiduciaries"), subject to authorization by the Treasurer, Assistant Treasurer, Secretary or Assistant Secretary of a fund or by an attorney in the Legal and Compliance Departments of UBS AM, for legitimate business purposes within the scope of their official duties and responsibilities, subject to such persons' continuing duty of confidentiality and duty not to trade on the basis of any material nonpublic information, as such duties are imposed under UBS AM's code of ethics, a fund's policies and procedures regarding the prevention of the misuse of inside information, by agreement or under applicable laws, rules and regulations: (i) persons who are subject to the code of ethics or the policies and procedures regarding the prevention of the misuse of inside information; (ii) an investment advisor, distributor, administrator, transfer agent, custodian or securities lending agent to a fund; (iii) an accounting firm, an auditing firm or outside legal counsel retained by UBS AM or a fund; (iv) an investment advisor to whom complete portfolio holdings are disclosed for due diligence purposes when the advisor is in merger or acquisition talks with a fund's current advisor; (v) a newly hired investment advisor or sub-advisor to whom complete portfolio holdings are disclosed prior to the time it commences its duties; and (vi) custodians and other third parties as necessary in connection with redemptions in kind of a fund's shares.

The frequency with which complete portfolio holdings may be disclosed between and among Affiliates and Fiduciaries, and the length of the lag, if any, between the date of the information and the date on which the information is disclosed between and among the Affiliates and Fiduciaries, is determined by the UBS AM Legal and Compliance Departments based on the facts and circumstances, including, without limitation, the nature of the portfolio holdings information to be disclosed and the risk of harm to a fund and its shareholders and the legitimate business purposes served by such disclosure.

**Complete and partial portfolio holdings—arrangements to disclose to service providers and fiduciaries.** As of the date of this SAI, the specific Service Providers, Affiliates and Fiduciaries with whom the funds have arrangements to provide portfolio holdings in advance of their release to the general public in the course of performing or to enable them to perform services for the funds are:

• State Street, each fund's custodian, accounting agent, securities lending agent, regulatory support service
provider and sub-administrator, receives portfolio holdings information daily on a real-time basis in connection with the services it provides.

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• Ernst & Young LLP, each fund's independent registered public accounting firm, receives portfolio holdings
information on an annual and semi-annual basis for financial reporting purposes. There is a 25-day lag between the date of portfolio holdings information and the date on which the information is disclosed to
Ernst & Young LLP for semi-annual reporting purposes. Ernst & Young LLP also receives portfolio holdings information annually at year-end for audit purposes. In this case, there is no lag between the date of the portfolio holdings
information and the date on which the information is disclosed to Ernst & Young LLP. In addition, Ernst & Young LLP receives holdings twice a year for fiscal income and excise tax provision reporting purposes with a 25-day lag time.

• A limited number of financial printers used by each fund to print and file its annual and semi-annual shareholder reports
and other regulatory materials. There is at least a two week lag between the date of the portfolio holdings information and the date on which the information is disclosed to the parties.

• The rating agency of Fitch Ratings Inc. may receive portfolio holdings information approximately 5 days after the end of
each month so that the funds may be included in the rating agency's industry reports and other materials. There is an approximately 5-day or longer lag between the date of the portfolio holdings information and the date on which the
information is disclosed to the rating agency.

• The rating agency of Moody's Investors Service, Inc. receives portfolio holdings information approximately 5 days
after the end of each month so that the funds may be included in the rating agency's industry reports and other materials. There is an approximately 5-day lag between the date of the portfolio holdings information and the date on which the
information is disclosed to the rating agency.

• Interactive Data Corporation receives portfolio holdings information daily on a real-time basis in connection with
providing pricing information for the funds' portfolio securities.

• Thomson Reuters receives portfolio holdings information weekly on a real-time basis in connection with providing pricing
information for the funds' portfolio securities.

• Investment Company Institute, the national association of US investment companies, including mutual funds, closed-end
funds, exchange-traded funds and unit investment trusts, receives portfolio holdings information on a monthly basis in order to compile and analyze industry data. There may be a delay of up to approximately 5 business days between the date of
the portfolio holdings information and the date on which the information is disclosed to the Investment Company Institute.

**Complete and partial portfolio holdings—disclosure to broker-dealers in the normal course of managing fund assets.** An investment advisor, administrator or custodian for a fund may, for legitimate business purposes within the scope of their official duties and responsibilities, disclose portfolio holdings (whether partial portfolio holdings or complete portfolio holdings) and other investment positions comprising a fund to one or more broker-dealers during the course of, or in connection with, normal day-to-day securities transactions with or through such broker-dealers subject to the broker-dealer's legal obligation not to use or disclose material nonpublic information concerning a fund's portfolio holdings, other investment positions or securities transactions without the consent of a fund or the Treasurer, Assistant Treasurer, Secretary or Assistant Secretary of the fund, or an attorney in the UBS AM Legal and Compliance Departments. A fund has not given its consent to any such use or disclosure and no person or agent of UBS AM is authorized to give such consent except as approved by a fund's board. In the event consent is given to disclose portfolio holdings to a broker-dealer, the frequency with which the portfolio holdings may be disclosed to a broker-dealer, and the length of the lag, if any, between the date of the information and the date on which the information is disclosed to the broker-dealer, is to be determined based on the facts and circumstances, including, without limitation, the nature of the portfolio holdings information to be disclosed, and the risk of harm to the fund, its shareholders, and the legitimate fund purposes served by such disclosure.

**Complete and partial portfolio holdings—disclosure as required by applicable law.** Fund portfolio holdings and other investment positions comprising a fund may be disclosed to any person as required by applicable laws,

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rules and regulations. Examples of such required disclosure include, but are not limited to, disclosure of fund portfolio holdings (i) in a filing or submission with the SEC or another domestic or foreign regulatory body, (ii) in connection with seeking recovery on defaulted bonds in a federal bankruptcy case, (iii) in connection with a lawsuit or (iv) as required by court order, subpoena or similar process (*e.g.*, arbitration proceedings). The UBS AM Legal Department must authorize the disclosure of portfolio holdings information when required for a legal or regulatory purpose. The UBS AM Legal Department may not be able to prevent or place restrictions on the disclosure of a fund's portfolio holdings when compelled by law or regulation to provide such information, even if the UBS AM Legal Department determines that such disclosure may not be in the best interest of fund shareholders or that a material conflict of interest is present or appears to be present. However, the UBS AM Legal Department will attempt to monitor the use of any fund portfolio holdings information disclosed as required by law or regulation.

**Disclosure of non-material information.** Policies and procedures regarding non-material information permit UBS AM fund officers, UBS AM fund portfolio managers, and senior officers of UBS AM Fund Treasury, UBS AM Legal and Compliance Departments, and anyone employed by or associated with UBS AM who has been authorized by the UBS AM Legal and Compliance Departments' representatives (collectively, "Approved Representatives") to disclose any views, opinions, judgments, advice or commentary, or any analytical, statistical, performance or other information, in connection with or relating to a fund or its portfolio holdings and/or other investment positions (collectively, "commentary and analysis") or any changes in the portfolio holdings of a fund that occurred after the most recent calendar-month end (or calendar-week end—in the case of a fund's public posting of portfolio holdings) ("recent portfolio changes") to any person if such information does not constitute material nonpublic information and complies with the portfolio holdings disclosure policies and procedures described above.

An Approved Representative must make a good faith determination whether the information constitutes material nonpublic information, which involves an assessment of the particular facts and circumstances.

UBS AM believes that in most cases recent portfolio changes that involve a few or even several securities in a diversified portfolio or commentary and analysis would be immaterial and would not convey any advantage to a recipient in making an investment decision concerning a fund. Nonexclusive examples of commentary and analysis about a fund include (i) the allocation of the fund's portfolio holdings and other investment positions among various asset classes, sectors, industries and countries, (ii) the characteristics of the fund's portfolio holdings and other investment positions, (iii) the attribution of fund returns by asset class, sector, industry and country, and (iv) the volatility characteristics of the fund. An Approved Representative may in its sole discretion determine whether to deny any request for information made by any person, and may do so for any reason or no reason.

"Approved Representatives" include persons employed by or associated with UBS AM who have been authorized by the Legal and Compliance Departments of UBS AM to disclose recent portfolio changes and/or commentary and analysis in accordance with the applicable policies and procedures.

**Prohibitions on disclosure of portfolio holdings.** No person is authorized to disclose fund portfolio holdings or other investment positions (whether online at http://www.ubs.com, in writing, by fax, by e-mail, orally or by other means) except in accordance with the applicable policies and procedures. In addition, no person is authorized to make disclosure pursuant to these policies and procedures if such disclosure is otherwise unlawful under the antifraud provisions of the federal securities laws (as defined in Rule 38a-1 under the Investment Company Act). Furthermore, UBS AM, in its sole discretion, may determine not to disclose portfolio holdings or other investment positions comprising a fund to any person who could otherwise be eligible to receive such information under the applicable policies and procedures, or may determine to make such disclosures publicly as provided by the policies and procedures.

**Prohibitions on receipt of compensation or other consideration.** The portfolio holdings disclosure policies and procedures prohibit a fund, its investment advisor and any other person to pay or receive any compensation or other consideration of any type for the purpose of obtaining disclosure of fund portfolio holdings or other investment positions. "Consideration" includes any agreement to maintain assets in a fund or in other investment companies or accounts managed by the investment advisor or by any affiliated person of the investment advisor.

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Organization of the Trust; trustees and officers; principal holders and management ownership of securities

The Trust was organized on April 29, 1998 as a statutory trust under the laws of Delaware and currently has thirteen series. The Trust has authority to establish additional series and issue an unlimited number of shares of beneficial interest of each existing or future series, par value of $0.001 per share.

The Trust is governed by a board of trustees, which oversees the funds' operations and which is authorized to establish additional series. Each trustee serves an indefinite term of office. The tables below show, for each trustee (sometimes referred to as "board member") and officer, his or her name, address and birth year, the position held with the Trust, the length of time served as trustee or officer of the Trust, the trustee's or officer's principal occupations during the last five years, the number of portfolios in the UBS fund complex overseen by the trustee or for which a person served as an officer, and other directorships held by such trustee.

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Independent trustees** | **Independent trustees** | **Independent trustees** | **Independent trustees** | **Independent trustees** | **Independent trustees** |
| **Name,<br>address,**<br>**and birth year** | **Position(s) held<br>with Trust** | **Term of office**<sup>1</sup>**<br>and length of<br>time served** | **Principal occupation(s)<br>during past 5 years** | **Number of portfolios<br>in fund complex<br>overseen by trustee** | **Other directorships held<br>by trustee** |
| Heather R. Higgins;<br> 1959<br> c/o Keith A. Weller<br> Fund Secretary<br> UBS Asset Management<br> (Americas) LLC<br> One North<br>Wacker Drive<br>Chicago, IL 60606 | Trustee and Chair of the Board of Trustees | Since 2005 (Trustee); since 2023 (Chair of the Board of Trustees) | Mrs. Higgins is the president and director of The Randolph Foundation (charitable foundation) (since 1991). Mrs. Higgins also serves (or has served) on the boards of several non-profit charitable groups, including the Independent Women's Forum (chairman) and the Philanthropy Roundtable (vice chairman). She also serves on the board of the Hoover Institution (from 2001 to 2007 and since 2009). | Mrs. Higgins is a director or trustee of 7 investment companies (consisting of 36 portfolios) for which UBS AM serves as investment advisor or manager. |  |
| Richard R. Burt,<br> 1947<br> McLarty Associates<br> 900 17th Street, N.W.<br>8th Floor<br> Washington, D.C. 20006 | Trustee | Since 1998 | Mr. Burt is a managing partner of McLarty Associates (a consulting firm) (since 2007). He was chairman of IEP Advisors (international investments and consulting firm) until 2009. | Mr. Burt is a trustee of 4 investment companies (consisting of 33 portfolios) for which UBS AM serves as investment advisor or manager. |  |
| Bernard H. Garil;<br> 1940<br> 6754 Casa Grande Way<br> Delray Beach, FL 33446 | Trustee | Since 2005 | Mr. Garil is retired (since 2001). He was a managing director at PIMCO Advisory Services (from 1999 to 2001) where he served as president of closed-end funds and vice-president of the variable insurance product funds advised by OpCap Advisors (until 2001). | Mr. Garil is a trustee of 4 investment companies (consisting of 33 portfolios) for which UBS AM serves as investment advisor or manager. | Mr. Garil is also a trustee for the Brooklyn College Foundation, Inc. (charitable foundation). |

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| | | | | | |
|:---|:---|:---|:---|:---|:---|
| **Independent trustees** | **Independent trustees** | **Independent trustees** | **Independent trustees** | **Independent trustees** | **Independent trustees** |
| **Name,<br>address,**<br>**and birth year** | **Position(s) held<br>with Trust** | **Term of office**<sup>1</sup>**<br>and length of<br>time served** | **Principal occupation(s)<br>during past 5 years** | **Number of portfolios<br>in fund complex<br>overseen by trustee** | **Other directorships held<br>by trustee** |
| Virginia G. Breen;<br> 1964<br> c/o Keith A. Weller<br> Fund Secretary<br> UBS Asset Management<br> (Americas) LLC<br> One North<br> Wacker Drive<br> Chicago, IL 60606 | Trustee | Since 2023 | Ms. Breen is a private investor and board member of certain entities (as listed herein). | Ms. Breen is a director or trustee of 7 investment companies (consisting of 36 portfolios) for which UBS AM serves as investment advisor or manager. | Director of: Paylocity Holding Corp.; UBS A&Q Fund Complex (3 funds); the Neuberger Berman Private Equity Registered Funds (18 funds); NB Asset Backed Credit Fund; certain funds in the Calamos Fund Complex (58 funds). Former Director of JLL Income Property Trust, Inc. (from 2004 to 2023) and Tech and Energy Transition Corporation (2021 to 2023). |
| David R. Malpass;<br> 1956<br> c/o Keith A. Weller<br> Fund Secretary<br> UBS Asset Management<br> (Americas) LLC<br> One North Wacker Drive<br> Chicago, IL 60606 | Trustee | Since 2023 | Mr. Malpass served as President of the World Bank Group from April 2019 to June 2023. Prior to that, he served as US Treasury Undersecretary for International Affairs (August 2017—April 2019) (Mr. Malpass also had previously served as a trustee of the funds from 2014 until 2017, when he entered public service.) | Mr. Malpass is a trustee of 4 investment companies (consisting of 33 portfolios) for which UBS AM serves as investment advisor or manager. | In his role as President of the World Bank Group, Mr. Malpass was President of, and Chairman of the Boards and Administrative Councils of, the following: International Bank for Reconstruction and Development; International Development Association; International Finance Corporation; Multilateral Investment Guarantee Agency; and International Centre for Settlement of Investment Disputes. In his role as Undersecretary of the US Treasury, Mr. Malpass was also on the boards of Overseas Private Investment Corporation (the US Government's development finance institution until it merged with another government entity in 2019) and Millennium Challenge Corporation (a US foreign aid agency). |

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<sup>1</sup> Each trustee holds office for an indefinite term.

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| | | | |
|:---|:---|:---|:---|
| **Officers** | **Officers** | **Officers** | **Officers** |
| **Name, address, and<br>birth year** | **Position(s) held<br>with Trust** | **Term of office**<sup>1</sup>**<br>and length of<br>time served** | **Principal occupation(s) during past 5 years** |
| Rose Ann Bubloski<sup>4</sup>;<br> 1968 | Vice President and Assistant Treasurer | Since 2011 | Ms. Bubloski is a director (since 2012) (prior to which she was an associate director (from 2008 to 2012)) and senior manager of fund accounting—US (previously named product control and investment support) at UBS AM and/or UBS AM (US) ("UBS AM—Americas region"). Ms. Bubloski is vice president and assistant treasurer of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. Ms. Bubloski is chief financial officer and treasurer of 5 investment companies (consisting of 7 portfolios) for which UBS AM serves as investment advisor or manager. |
| Mark E. Carver<sup>2</sup>;<br> 1963 | President | Since 2023 | Mr. Carver is an executive director and senior member of UBS AM's Americas Products team (since rejoining UBS AM in 2022). In addition to his fund board relations and governance role, he serves as a regional strategic product shelf manager, including UBS AM's strategic product alignment with UBS Financial Services Inc. Mr. Carver previously served in the role of president of the funds from 2010 to 2018 before moving to a senior product role at UBS Financial Services Inc. until 2020. Before rejoining UBS AM, Mr. Carver served in a consulting capacity for FLX Networks, a firm serving both the asset management and wealth management industries. He is president of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. |
| Michael Gleason<sup>2</sup>;<br> 1982 | Vice President | Since 2024 | Mr. Gleason is an executive director since 2023, and operational tax specialist for UBS AM—Americas region, prior to which he was a senior manager at Deloitte (from 2014 until 2023). Mr. Gleason is a vice president of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. |
| Joanne M. Kilkeary<sup>4</sup>;<br> 1968 | Vice President, Treasurer, Chief Financial Officer and Principal Accounting Officer | Since 1999 (Vice President) and since 2017 (Treasurer and Principal Accounting Officer) | Ms. Kilkeary is an executive director (since 2013) and head of fund accounting—US (since 2020) (prior to which she was head of regulatory, tax, audit and board governance for product control and investment support (from 2017 until 2020)) of UBS AM—Americas region. Ms. Kilkeary is a vice president, treasurer, Chief Financial Officer and principal accounting officer of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. |
| Leesa Merrill<sup>3</sup>;<br> 1978 | Chief Compliance Officer | Since 2022 | Ms. Merrill is an executive director (since March 2023) (prior to which she was a director (from 2014 until March 2023) and served as head of compliance risk (from 2020 to 2022) (prior to which she was a senior compliance officer (from 2004 until 2020) for UBS AM—Americas region. Ms. Merrill serves as chief compliance officer of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. |
| Robert Sabatino<sup>3</sup>;<br> 1973 | Vice President | Since 2001 | Mr. Sabatino is a managing director (since 2010), head of global liquidity portfolio management (since 2015), and portfolio manager of UBS AM—Americas region in the short duration fixed income group (since 2000). Mr. Sabatino is a vice president of three investment companies (consisting of 32 portfolios) for which UBS AM serves as investment advisor or manager. |

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| | | | |
|:---|:---|:---|:---|
| **Officers** | **Officers** | **Officers** | **Officers** |
| **Name, address, and<br>birth year** | **Position(s) held<br>with Trust** | **Term of office**<sup>1</sup>**<br>and length of<br>time served** | **Principal occupation(s) during past 5 years** |
| Eric Sanders<sup>5</sup>;<br> 1965 | Vice President and Assistant Secretary | Since 2005 | Mr. Sanders is a director and associate general counsel with UBS Business Solutions US LLC (since 2017) and also with UBS AM—Americas region (since 2005). Mr. Sanders is a vice president and assistant secretary of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. |
| Philip Stacey<sup>3</sup>;<br> 1985 | Vice President and Assistant Secretary | Since 2018 | Mr. Stacey is a managing director (since 2023, prior to which he was an executive director (from 2019 until 2023)) and Head of Legal of UBS AM—Americas Region (since 2023) prior to which he was Head of Derivatives and Trading Legal and associate general counsel (from 2017 through 2022) with UBS Business Solutions US LLC and also with UBS AM—Americas region (since 2015). Mr. Stacey is a vice president and assistant secretary of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager. |
| David Walczak<sup>3</sup>;<br> 1983 | Vice President | Since 2016 | Mr. Walczak is a managing director (since 2024) (prior to which he was an executive director from 2016 until 2024), head of US money markets (since 2015) and portfolio manager of UBS AM—Americas region. Mr. Walczak is a vice president of three investment companies (consisting of 32 portfolios) for which UBS AM serves as investment advisor or manager. |
| Keith A. Weller<sup>3</sup>;<br> 1961 | Vice President and Secretary | Since 1998 (Vice President) and since 2019 (Secretary) | Mr. Weller is an executive director (since 2005) and deputy general counsel (since 2019) and Head of Registered Funds Legal (since 2022) with UBS Business Solutions US LLC (since 2017) and also with UBS AM—Americas region (since 2005) and has been an attorney with affiliated entities since 1995. Mr. Weller is a vice president and secretary of 6 investment companies (consisting of 42 portfolios) for which UBS AM serves as investment advisor or manager, and is also involved with other funds for which UBS AM or an affiliate serves as investment advisor or administrator. |

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<sup>1</sup> Officers are appointed by the trustees and serve at the pleasure of the board.

<sup>2</sup> This person's business address is 1285 Avenue of the Americas, New York, NY 10019.

<sup>3</sup> This person's business address is One North Wacker Drive, Chicago, IL 60606.

<sup>4</sup> This person's business address is 1000 Harbor Boulevard, Weehawken, NJ 07086.

<sup>5</sup> This person's business address is 11 Madison Avenue, New York, NY 10010.

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| | |
|:---|:---|
| **Information about trustee ownership of funds' shares** | **Information about trustee ownership of funds' shares** |
| **Trustee** | **Dollar range of<br>equity securities in<br>UBS Select<br>Treasury<br>Institutional Fund**<sup>1</sup> |
|  ***Independent trustees*** |  |
| Heather R. Higgins |  |
| Richard R. Burt |  |
| Bernard H. Garil |  |
| Virginia G. Breen |  |
| David R. Malpass |  |
| **Trustee** | **Dollar range of<br>equity securities in<br>UBS Select<br>Treasury<br>Preferred Fund**<sup>1</sup> |
|  ***Independent trustees*** |  |
| Heather R. Higgins |  |
| Richard R. Burt |  |
| Bernard H. Garil |  |
| Virginia G. Breen |  |
| David R. Malpass |  |

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| | | |
|:---|:---|:---|
| **Trustee** | **Dollar range of<br>equity securities in<br>UBS Prime<br>Reserves Fund**<sup>1</sup> | **Dollar range of<br>equity securities in<br>UBS Prime<br>Preferred Fund**<sup>1</sup> |
|  ***Independent trustees*** |  |  |
| Heather R. Higgins |  |  |
| Richard R. Burt |  |  |
| Bernard H. Garil | Over $100,000 |  |
| Virginia G. Breen |  |  |
| David R. Malpass |  |  |

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| | | |
|:---|:---|:---|
| **Trustee** | **Dollar range of<br>equity securities in<br>UBS Select<br>Government<br>Institutional Fund**<sup>1</sup> | **Dollar range of<br>equity securities in**<br>**UBS Select<br>Government<br>Preferred Fund**<sup>1</sup> |
|  ***Independent trustees*** |  |  |
| Heather R. Higgins |  |  |
| Richard R. Burt |  |  |
| Bernard H. Garil |  |  |
| Virginia G. Breen |  |  |
| David R. Malpass |  |  |

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| | | | |
|:---|:---|:---|:---|
| **Trustee** | **Dollar range of<br>equity securities in<br>UBS Select<br>100% US Treasury<br>Institutional Fund** | **Dollar range of<br>equity securities in<br>UBS Select<br>100% US Treasury<br>Preferred Fund** | **Aggregate<br>dollar range of<br>equity securities in all<br>registered investment<br>companies overseen by<br>trustee for which<br>UBS AM serves as<br>investment advisor or<br>manager**<sup>1</sup> |
|  ***Independent trustees*** |  |  |  |
| Heather R. Higgins |  |  | Over $100,000 |
| Richard R. Burt |  |  |  |
| Bernard H. Garil |  |  | Over $100,000 |
| Virginia G. Breen |  |  |  |
| David R. Malpass |  |  |  |

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<sup>1</sup> Information regarding ownership is as of December 31, 2025, unless otherwise noted.

**Leadership structure and qualifications of board of trustees** 

The board is responsible for oversight of the funds. The board is currently composed of five trustees, all of whom are not "interested persons" of the funds as that term is defined by the Investment Company Act ("Independent Trustees"). The board members have selected Mrs. Higgins, an Independent Trustee, to act as chair of the board. The chair of the board's role is to preside at all meetings of the board and generally to act as a liaison with service providers, officers, attorneys and other trustees between meetings. The chair may also perform such other functions as may be delegated by the board from time to time. The board has established an Audit Committee and Nominating and Corporate Governance Committee to assist the board in the oversight and direction of the business and affairs of the funds, and from time to time may establish ad hoc committees, informal working groups or designate one or more members to review and address the policies and practices of the funds or to liaise with the funds' Chief Compliance Officer or service providers, including staff of UBS AM, with respect to certain specified matters. The board meets at regularly scheduled meetings five times throughout the year. In addition, the trustees may meet in person or by telephone at special meetings or on an informal basis at other times. Each committee meets as appropriate to conduct the oversight functions delegated to the committee by the board and reports its findings to the board. The board and Audit Committee conduct annual assessments of their oversight function and structure. The Independent Trustees have also engaged independent legal counsel to assist them in performing their oversight responsibilities. The trustees have determined that the board's leadership and committee structure is appropriate because it allows the board to exercise informed and independent judgment over the matters under its purview and allocate areas of responsibility among committees of Independent Trustees and the full board in a manner that enhances the full board's oversight.

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The funds have engaged UBS AM to manage each fund on a day-to-day basis. The board is responsible for overseeing UBS AM and other service providers in the operations of the funds in accordance with the Investment Company Act, applicable state and other laws, and the funds' charter. The board reviews, on an ongoing basis, the funds' performance, operations and investment strategies and techniques. The board also conducts reviews of UBS AM and its role in running the operations of the funds.

The board has concluded that, based on each trustee's experience, qualifications, attributes or skills on an individual basis and in combination with those of the other trustees, each trustee should serve as a trustee. In determining that a particular trustee is qualified to serve as a trustee, the board has considered a variety of criteria, none of which, in isolation, was controlling. The board believes that, collectively, the trustees have balanced and diverse experience, skills, attributes and qualifications, which allow the board to operate effectively in governing the funds and protecting the interests of shareholders. Among the attributes common to all trustees are their ability to review critically, evaluate, question and discuss information provided to them, to interact effectively with other board members, UBS AM, other service providers, counsel and the independent registered public accounting firm, and to exercise effective business judgment in the performance of their duties as trustees. In addition, the board has taken into account the actual service and commitment of the trustees during their tenure in concluding that each should continue to serve. A trustee's ability to perform his or her duties effectively may have been attained through a trustee's educational background or professional training; business, consulting, public service or academic positions; experience from service as a trustee of the funds, other funds in the fund complex, other investment funds, public companies, or nonprofit entities or other organizations; and/or other life experiences. Set forth below is a brief discussion of the specific experience, qualifications, attributes or skills of each trustee that led the board to conclude that he or she should serve as a trustee.

Amb. Burt has served as a board member of the Trust and as a director/trustee of the other funds in the fund complex for over two decades, including as a member and/or chair of various board committees. Amb. Burt has many years experience in advising companies regarding international investment and risk management. Amb. Burt has served on the boards of directors of The Central Europe, Russia and Turkey Fund, Inc., The European Equity Fund, Inc. and The New Germany Fund, Inc. (and served as a member of each such fund's audit, nominating and governance committees) and has served as a director on other corporate boards. Prior to joining McLarty Associates in 2007, Amb. Burt was chairman of Diligence Inc. (information and risk management firm). Amb. Burt was the chief negotiator in the Strategic Arms Reduction Talks with the former Soviet Union (1989-1991) and the US Ambassador to the Federal Republic of Germany (1985-1989). He had also been a partner of McKinsey & Company (management consulting firm).

Mr. Garil and Mrs. Higgins were elected as directors/trustees of the funds in the fund complex during 2005-2006. Mr. Garil and Mrs. Higgins also serve as members of various board committees.

Mr. Garil has over four decades of experience in the fund management business and for much of that time he served as an executive of a fund adviser and as a member of the boards of funds, trust companies, and non-profit organizations, including OFI Trust Company and the Leukemia & Lymphoma Society. He began his career at the US Securities and Exchange Commission.

Mrs. Higgins has experience as a portfolio manager for a major US trust bank and has held senior executive positions and/or directorships at several major charitable organizations.

Ms. Breen became a trustee in 2023. She has more than 25 years of experience in the financial services industry. She also has experience serving on boards of other entities, including other investment companies.

Mr. Malpass became a trustee in 2023. In his role as President and Chairman of the Board of Executive Directors of the World Bank Group, Mr. Malpass led the Bank Group's public and private sector operations to a record $122.6 billion in commitments in fiscal year 2023, including record investments in climate finance, pandemic preparedness,

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and debt sustainability. In addition to having been the President of the World Bank Group, he served as US Treasury Undersecretary for International Affairs and has held various other government positions. He was also Chief Economist at Bear, Stearns & Co. Mr. Malpass also had previously served as a trustee of the funds from 2014 until 2017, when he entered public service.

Additional details about each trustee's professional experience is included above in the table in the section captioned "Organization of the Trust; trustees and officers; principal holders and management ownership of securities." That table contains information regarding other directorships currently held by board members.

**Risk oversight** 

The funds are subject to a number of risks, including investment, liquidity, compliance, operational and valuation risks, among others. Risk oversight forms part of the board's general oversight of each fund's investment program and operations and is addressed as part of various regular board and committee activities. Day-to-day risk management with respect to each fund is the responsibility of UBS AM or other service providers (depending on the nature of the risk), subject to supervision by UBS AM. Each of UBS AM and other service providers have their own independent interest in risk management and their policies and methods of risk management may differ from the funds and each other's in the setting of priorities, the resources available or the effectiveness of relevant controls. As a result, the board recognizes that it is not possible to identify all of the risks that may affect the funds or to develop processes and controls to eliminate or mitigate their occurrence or effects, and that some are simply beyond any control of the funds or UBS AM, its affiliates or other service providers. As part of its regular oversight of the funds, the board, directly or through a committee, reviews reports from, among others, management, the funds' Chief Compliance Officer, its independent registered public accounting firm, counsel, and internal auditors for UBS AM or its affiliates, as appropriate, regarding risks faced by the funds and UBS AM's risk oversight programs. The board has appointed a Chief Compliance Officer who oversees the implementation and testing of each fund's compliance program and reports to the board regarding compliance matters for the funds and their service providers; the board has designated one of its members to liaise with the Chief Compliance Officer between board meetings to assure that significant compliance issues identified by the Chief Compliance Officer will be brought to the attention of the full board in a timely and appropriate manner. The board may, at any time and in its discretion, change the manner in which it conducts risk oversight.

**Committees** 

The Trust has an Audit Committee and a Nominating and Corporate Governance Committee. The members of the Audit Committee are currently the Independent Trustees. Virginia G. Breen is chairperson of the Audit Committee. The following Independent Trustees are members of the Nominating and Corporate Governance Committee: Richard R. Burt (chairman), Bernard H. Garil and David R. Malpass.

The Audit Committee is responsible for, among other things: (i) overseeing the scope of a fund's audit; (ii) overseeing a fund's accounting and financial reporting policies, practices and internal controls; and (iii) approving, and recommending to the board for ratification, the selection, appointment, retention or termination of a fund's independent registered public accounting firm, as well as determining the compensation thereof. In furtherance of its duties, the Audit Committee also is responsible for, among other things: obtaining assurance from a fund's independent registered public accounting firm of its independence and discussing any disclosed relationships or services that may diminish the objectivity and independence of the independent registered public accounting firm; inquiring as to a fund's qualification under Subchapter M of the Internal Revenue Code and the amounts distributed and reported to shareholders; reviewing with the independent registered public accounting firm any problems or difficulties with the audit; and reporting to the full board and making recommendations as it deems necessary or appropriate. Although the Audit Committee has the responsibilities described above, it is not responsible for planning or conducting a fund's audit or determining whether a fund's financial statements are complete and accurate and are in accordance with US generally accepted accounting principles. Absent actual knowledge to the contrary, Audit Committee members are entitled to rely on the accuracy of the information they receive from persons within and outside a fund.

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The Audit Committee normally meets in conjunction with regular board meetings, or more frequently as called by its chairperson. During the funds' fiscal year ended April 30, 2025, the Audit Committee held five meetings.

The Trust's board has also established a Nominating and Corporate Governance Committee that acts pursuant to a written charter. The Nominating and Corporate Governance Committee is responsible for, among other things: selecting, evaluating and recommending to the board candidates to be nominated as additional Independent Trustees; making recommendations to the board with respect to compensation of board and committee members; performing an annual evaluation of the board and its committees; reporting on such evaluation to the board; and performing such other corporate governance functions as the board may authorize. The Nominating and Corporate Governance Committee held five meetings during the fiscal year ended April 30, 2025. The Nominating and Corporate Governance Committee will consider nominees recommended by shareholders if a vacancy among the Independent Trustees occurs. In order to recommend a nominee, a shareholder should send a letter to the chairperson of the Nominating and Corporate Governance Committee, Mr. Burt, care of the Secretary of the Trust at UBS Asset Management (Americas) LLC, One North Wacker Drive, Chicago, IL 60606, and indicate on the envelope "Nominating and Corporate Governance Committee." The shareholder's letter should state the nominee's name and should include the nominee's *résumé* or *curriculum vitae*, and must be accompanied by a written consent of the individual to stand for election if nominated for the board and to serve if elected by shareholders.

**Information about Independent Trustee ownership of securities issued by UBS AM or any company controlling, controlled by or under common control with UBS AM** 

As of December 31, 2025, the Independent Trustees and their immediate family members did not own any securities issued by UBS AM or any company controlling, controlled by or under common control with UBS AM.

**Compensation** 

Each Independent Trustee receives, in the aggregate from the UBS AM funds he or she oversees, an annual retainer of $300,000. The chairperson of the board receives annually an additional $85,000; the chairperson of the Audit Committee receives annually an additional $35,000; and the chairperson of the Nominating and Corporate Governance Committee receives annually an additional $25,000. In addition, a board member who undertakes any special assignment(s) to provide assistance in coordinating the board's oversight of compliance matters (Heather R. Higgins) or contract reconsideration matters (Bernard H. Garil and David R. Malpass) receives annually an additional $25,000. The foregoing fees are allocated among all such funds as follows: (i) one-half of the expense is allocated pro rata based on the funds' relative net assets at the end of the calendar quarter preceding the date of payment; and (ii) one-half of the expense is allocated according to the number of such funds. No officer, director or employee of UBS AM or any of its affiliates presently receives any compensation from the funds for acting as a board member or officer. All board members are reimbursed for expenses incurred in attending meetings.

The table below includes certain information relating to the compensation of the Trust's current board members and the compensation of those board members from all funds for which UBS AM or an affiliate served as an investment advisor or manager during the periods indicated.

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| | |
|:---|:---|
| **Compensation table**<sup>1</sup><br>**Name of person, position** | <br>**UBS Select<br>Treasury<br>Institutional<br>Fund**<sup>3</sup> |
| Heather R. Higgins, Trustee<sup>2</sup> | $20385 |
| Richard R. Burt, Trustee | 15942 |
| Bernard H. Garil, Trustee | 15942 |
| Virginia G. Breen, Trustee<sup>2</sup> | 16465 |
| David R. Malpass, Trustee | 15942 |

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| | |
|:---|:---|
| **Compensation table**<sup>1</sup><br>**Name of person, position** | <br>**UBS Select<br>Treasury<br>Preferred<br>Fund**<sup>3</sup> |
| Heather R. Higgins, Trustee<sup>2</sup> | $23848 |
| Richard R. Burt, Trustee | 18650 |
| Bernard H. Garil, Trustee | 18650 |
| Virginia G. Breen, Trustee<sup>2</sup> | 19262 |
| David R. Malpass, Trustee | 18650 |

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| | | |
|:---|:---|:---|
| **Name of person, position** | **UBS<br>Prime**<br> **Reserves<br>Fund**<sup>3</sup> | **UBS<br>Prime<br>Preferred<br>Fund**<sup>3</sup> |
| Heather R. Higgins, Trustee<sup>2</sup> | $16325 | $14192 |
| Richard R. Burt, Trustee | 12767 | 11099 |
| Bernard H. Garil, Trustee | 12767 | 11099 |
| Virginia G. Breen, Trustee<sup>2</sup> | 13186 | 11463 |
| David R. Malpass, Trustee | 12767 | 11099 |

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| | | |
|:---|:---|:---|
| **Name of person, position** | **UBS Select<br>Government<br>Institutional<br>Fund**<sup>3</sup> | **UBS Select<br>Government<br>Preferred<br>Fund**<sup>3</sup> |
| Heather R. Higgins, Trustee<sup>2</sup> | $12814 | $18067 |
| Richard R. Burt, Trustee | 10021 | 14129 |
| Bernard H. Garil, Trustee | 10021 | 14129 |
| Virginia G. Breen, Trustee<sup>2</sup> | 10350 | 14592 |
| David R. Malpass, Trustee | 10021 | 14129 |

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| | | | |
|:---|:---|:---|:---|
| **Name of person, position** | **UBS Select<br>100% US<br>Treasury<br>Preferred<br>Fund**<sup>3</sup> | **UBS Select<br>100% US<br>Treasury**<br> **Institutional<br>Fund**<sup>3</sup> | **Total<br>compensation<br>from the<br>Trust and the<br>fund<br>complex**<sup>4</sup> |
| Heather R. Higgins, Trustee<sup>2</sup> | $7840 | $9041 | $452700 |
| Richard R. Burt, Trustee | 6131 | 7070 | 305000 |
| Bernard H. Garil, Trustee | 6131 | 7070 | 305000 |
| Virginia G. Breen, Trustee<sup>2</sup> | 6332 | 7302 | 397700 |
| David R. Malpass, Trustee | 6131 | 7070 | 305000 |

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<sup>1</sup> Only Independent Trustees were compensated by the funds for which UBS AM serves as investment advisor or manager.

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<sup>2</sup> Mrs. Higgins and Ms. Breen also serve on the boards of other registered investment companies for which UBS AM serves as investment advisor or manager.

<sup>3</sup> Represents fees paid to each trustee during the fiscal year ended April 30, 2025.

<sup>4</sup> Represents fees paid during the calendar year ended December 31, 2024 to each board member by: (a) 4 investment companies in the case of Messrs. Burt, Garil and Malpass; and (b) 7 investment companies in the case of Mrs. Higgins and Ms. Breen, for which UBS AM served as investment advisor or manager. No fund within the UBS fund complex has a bonus, pension, profit sharing or retirement plan. 

**Principal holders and management ownership of securities** 

As of January 21, 2026, trustees and officers owned in the aggregate less than 1% of the outstanding shares of each fund.

As of January 2, 2026, the following shareholders were shown in the Trust's records as owning more than 5% of a fund's outstanding shares. Shareholders owning of record or beneficially more than 25% of a fund's outstanding shares may be deemed to "control" the fund within the meaning of the Investment Company Act. Except as listed below, the Trust does not know of any other person who owns beneficially 5% or more of a fund's shares as of such date:

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| | | |
|:---|:---|:---|
| **Fund\*** | **Name and Address<sup>1</sup>** | **Percentage of shares<br>beneficially owned as<br>of January 2, 2026** |
| UBS Select Government Preferred Fund | UBS FINANCIAL SERVICES INC FBO NATIONAL PHILANTHROPIC TRUST PERSONAL GIVING | 9.98% |
| UBS Select Government Preferred Fund | UBS Financial Services Inc. FBO Russell Goldencloud Savage TTE | 5.32% |
| UBS Select Treasury Institutional Fund | HARE & CO | 6.61% |
| UBS Select Treasury Preferred Fund | UBS FINANCIAL SERVICES INC FBO NATIONAL PHILANTHROPIC TRUST PERSONAL GIVING | 6.32% |

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<sup>1</sup> The shareholder listed may be contacted c/o UBS Asset Management (US) Inc., Compliance Department, 1285 Avenue of the Americas, New York, NY 10019.

\* Because Token-Enabled Shares had not commenced operations prior to January 26, 2026, no person owned (of record or beneficially) 5% or more of Token-Enabled Shares as of that date. 

Investment advisory, administration and principal

underwriting arrangements

**Investment advisory and administration arrangements—master level.** UBS AM acts as investment advisor and administrator for the master funds in which the funds invest their assets. Pursuant to an investment management contract with respect to each master fund (except 100% US Treasury Master Fund) and a seperate investment management contract with respect to 100% US Treasury Master Fund (each, a "Management Contract"), each fund is allocated an annual fee from the corresponding master fund, computed daily and paid monthly, at an annual rate of 0.100% of the fund's average daily net assets up to and including $30 billion; 0.0975% of the fund's average daily net assets above $30 billion up to and including $40 billion; 0.0950% of the fund's average daily net assets above $40 billion up to and including $50 billion; 0.0925% of the fund's average daily net assets above $50 billion up to and including $60 billion; and 0.0900% of the fund's average daily net assets above $60 billion.

Under the terms of the Management Contract with respect to each master fund (except 100% US Treasury Master Fund), UBS AM bears all expenses incurred in a fund's operation other than the fee payable under the Management Contract, fees and expenses (including counsel fees) of the Independent Trustees, interest (except interest on borrowings), taxes, the cost (including brokerage commissions and other transaction costs, if any) of securities purchased or sold by a fund and any losses incurred in connection therewith and extraordinary expenses (such as costs of litigation to which the Trust or a fund is a party and of indemnifying officers and trustees of the trust).

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Expenses borne by UBS AM under the Management Contract with respect to each master fund (except 100% US Treasury Master Fund) include the following (or a fund's share of the following): (1) organizational expenses (if these expenses are amortized over a period of more than one year, UBS AM will bear in any one year only that portion of the organizational expenses that would have been borne by the fund in that year), (2) filing fees and expenses relating to the registration and qualification of the shares of the fund under federal and state securities laws and maintaining such registration and qualifications, (3) fees and salaries payable to the trustees (other than the Independent Trustees) and officers, (4) all expenses incurred in connection with the services of the trustees (other than the Independent Trustees), including travel expenses, (5) costs of any liability, uncollectable items of deposit and other insurance or fidelity bonds, (6) ordinary legal, accounting and auditing expenses, excluding legal fees of special counsel for the Independent Trustees and, as noted above, excluding extraordinary expenses, such as litigation or indemnification expenses, (7) charges of custodians, transfer agents and other agents, (8) costs of preparing share certificates (if any), (9) expenses of setting in type and printing prospectuses and supplements thereto, reports and statements to shareholders and proxy materials for existing shareholders, (10) fees, voluntary assessments and other expenses incurred in connection with membership in investment company organizations, (11) costs of mailing and tabulating proxies and costs of meetings of shareholders, the board and any committees thereof, (12) the cost of investment company literature and other publications provided to the trustees and officers, (13) costs of mailing, stationery and communications equipment, (14) expenses incident to any dividend, withdrawal or redemption options, (15) charges and expenses of any outside pricing service used to value portfolio securities, and (16) interest on borrowings.

Although UBS AM is not obligated to pay the ordinary fees and expenses of the Independent Trustees, the Management Contract with respect to each master fund (except 100% US Treasury Master Fund) requires that UBS AM reduce its advisory and administrative fees by an amount equal to those fees and expenses.

Under the terms of the Management Contract with respect to 100% US Treasury Master Fund, the master fund bears all expenses incurred in its operation that are not specifically assumed by UBS AM. Expenses borne by the master fund include the following: (1) the cost (including brokerage commissions, if any) of securities purchased or sold by the fund and any losses incurred in connection therewith; (2) fees payable to and expenses incurred on behalf of the fund by UBS AM; (3) organizational expenses; (4) filing fees and expenses relating to the registration and qualification of the fund's shares under federal and state securities laws and maintenance of such registrations and qualifications; (5) fees and salaries payable to trustees who are not interested persons (as defined in the Investment Company Act) of the Trust by reason of affiliation with UBS AM or any of UBS AM's affiliates; (6) all expenses incurred in connection with the board members' services, including travel expenses; (7) taxes (including any income or franchise taxes) and governmental fees; (8) costs of any liability, uncollectible items of deposit and other insurance or fidelity bonds; (9) any costs, expenses or losses arising out of a liability of or claim for damages or other relief asserted against the fund for violation of any law; (10) legal, accounting and auditing expenses, including legal fees of special counsel for the trustees who are not interested persons (as defined in the Investment Company Act) of the Trust by reason of affiliation with UBS AM or any of UBS AM's affiliates; (11) charges of custodians, transfer agents and other agents; (12) costs of preparing share certificates; (13) expenses of setting in type and printing prospectuses and supplements thereto, statements of additional information and supplements thereto, reports and proxy materials for existing shareholders and costs of mailing such materials to existing shareholders; (14) any extraordinary expenses (including fees and disbursements of counsel) incurred by the fund; (15) fees, voluntary assessments and other expenses incurred in connection with membership in investment company organizations; (16) costs of mailing and tabulating proxies and costs of meetings of shareholders, the board and any committees thereof; (17) the cost of investment company literature and other publications provided to trustees and officers; (18) costs of mailing, stationery and communications equipment; (19) expenses incident to any dividend, withdrawal or redemption options; (20) charges and expenses of any outside pricing service used to value portfolio securities; and (21) interest on borrowings of the fund.

Each Management Contract is terminable (1) by a corresponding master fund by vote of the Master Trust's board or by the holders of a majority of the outstanding voting securities of that master fund at any time without penalty, on

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60 days' written notice to UBS AM, and (2) by UBS AM at any time, without the payment of any penalty, on 60 days' written notice to the Trust.

100% US Treasury Master Fund and UBS AM have entered into a written fee waiver/expense reimbursement agreement pursuant to which UBS AM is contractually obligated to waive its management fees and/or reimburse expenses so that the master fund's ordinary total operating expenses through August 31, 2026 (excluding dividend expense, borrowing costs, and interest expense relating to short sales, and expenses attributable to investment in other investment companies, interest, taxes, brokerage commissions, expenses related to shareholders' meetings and extraordinary expenses) would not exceed 0.10% for the master fund. The master fund has agreed to repay UBS AM for any waived fees/reimbursed expenses to the extent that it can do so over the following three fiscal years without causing the master fund's expenses in any of those three years to exceed the lesser of any applicable expense limit that is in place for the master fund (i) at the time of the waiver or reimbursement, or (ii) at the time of recoupment, and that UBS AM has not waived the right to do so. The fee waiver/expense reimbursement agreement may be terminated by the master fund's board at any time and also will terminate automatically upon the expiration or termination of the master fund's advisory contract with UBS AM. Upon termination of the agreement, however, UBS AM's three year recoupment rights will survive.

In addition, UBS AM may voluntarily undertake to waive fees in the event that fund yields drop below a certain level. These additional undertakings are voluntary and not contractual and may be terminated at any time and are not subject to future recoupment.

During each of the fiscal years indicated, the funds were allocated the following fees under the Management Contract, after giving effect to the following amounts in fee waivers and/or other credits.

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| | | | |
|:---|:---|:---|:---|
|  | | **Fiscal years ended April 30,** | **Fiscal years ended April 30,** |
| | **2025** | **2024** | **2023** |
|  **UBS Select Treasury Institutional Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | $18285932 | $15099617 | $9205294 |
| Fee amount waived | 0 | 0 |  |
|  **UBS Select Treasury Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | 22057676 | 20031191 | 15863311 |
| Fee amount waived | 0 | 0 |  |
|  **UBS Prime Reserves Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | 12074256 | 6658901 | 3357775 |
| Fee amount waived | 0 | 0 |  |
|  **UBS Prime Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | 9672379 | 5278814 | 2202401 |
| Fee amount waived | 0 | 0 |  |
|  **UBS Select Government Institutional Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | 9091535 | 6684401 | 1445421 |
| Fee amount waived | 0 | 0 | 1905124 |
|  **UBS Select Government Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | 15555112 | 12308868 | 3177030 |
| Fee amount waived | 0 | 0 | 3489288 |

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| | | | |
|:---|:---|:---|:---|
|  | | **Fiscal years ended April 30,** | **Fiscal years ended April 30,** |
| | **2025** | **2024** | **2023** |
|  **UBS Select 100% US Treasury Institutional Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | $4047900 | $1117 | $— \* |
| Fee amount waived | 0 | 0 | — \* |
|  **UBS Select 100% US Treasury Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers or credits | 2840600 | 2214 | — \* |
| Fee amount waived | 0 | 0 | — \* |

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\* UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund commenced operations on March 13, 2024. Therefore, no fees were paid by each fund for the fiscal year ended April 30, 2023. 

**Administration arrangements—feeder level** 

**UBS Select Treasury Institutional Fund, UBS Select Treasury Preferred Fund, UBS Prime Reserves Fund, UBS Prime Preferred Fund, UBS Select Government Institutional Fund, UBS Select Government Preferred Fund, UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund.** UBS AM acts as administrator of the funds pursuant to administration contracts with respect to such funds (each an "Administration Contract"). Under its respective Administration Contract, each fund pays UBS AM an annual fee, computed daily and paid monthly, at an annual rate of 0.08% of its average daily net assets.

Expenses borne by UBS AM under an Administration Contract for the funds listed above (except UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund) include the following (or a fund's share of the following): (1) organizational expenses (if these expenses are amortized over a period of more than one year, UBS AM will bear in any one year only that portion of the organizational expenses that would have been borne by the fund in that year), (2) filing fees and expenses relating to the registration and qualification of the shares of the fund under federal and state securities laws and maintaining such registration and qualifications, (3) fees and salaries payable to the trustees (other than the Independent Trustees) and officers, (4) all expenses incurred in connection with the services of trustees (other than the Independent Trustees), including travel expenses, (5) costs of any liability, uncollectible items of deposit and other insurance and fidelity bonds, (6) legal, accounting and auditing expenses, excluding legal fees of special counsel for the Independent Trustees and excluding extraordinary expenses, such as litigation or indemnification expenses, (7) charges of custodians, transfer agents and other agents, (8) costs of preparing share certificates, if any, (9) expenses of setting in type and printing prospectuses and supplements thereto, statements of additional information and supplements thereto, reports and proxy materials for existing shareholders, (10) costs of mailing prospectuses and supplements thereto, statements of additional information and supplements thereto, reports and proxy materials for existing shareholders, (11) fees, voluntary assessments and other expenses incurred in connection with membership in investment company organizations, (12) the cost of mailing and tabulating proxies and costs of meetings of shareholders, the Board and any committees thereof, (13) the cost of investment company literature and other publications provided to the trustees and officers, (14) costs of mailing, stationery and communications equipment, (15) expenses incident to any dividend, withdrawal or redemption options, and (16) interest on borrowings.

Although UBS AM is not obligated to pay the ordinary fees and expenses of the Independent Trustees, the Administration Contract for such funds requires that UBS AM reduce its advisory and administrative fees by an amount equal to those fees and expenses.

Under the terms of the Administration Contract with respect to UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund, each such fund bears all expenses incurred in its operation that are not specifically assumed by UBS AM. Expenses borne by the funds include the following: (1) fees payable to and expenses incurred on behalf of the fund by UBS AM; (2) organizational expenses; (3) filing fees and expenses

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relating to the registration and qualification of the fund's shares under federal and state securities laws and maintenance of such registrations and qualifications; (4) fees and salaries payable to trustees who are not interested persons (as defined in the Investment Company Act) of the Trust by reason of affiliation with UBS AM or any of UBS AM's affiliates; (5) all expenses incurred in connection with the board members' services, including travel expenses; (6) taxes (including any income or franchise taxes) and governmental fees; (7) costs of any liability, uncollectible items of deposit and other insurance or fidelity bonds; (8) any costs, expenses or losses arising out of a liability of or claim for damages or other relief asserted against the fund for violation of any law; (9) legal, accounting and auditing expenses, including legal fees of special counsel for the trustees who are not interested persons (as defined in the Investment Company Act) of the Trust by reason of affiliation with UBS AM or any of UBS AM's affiliates; (10) charges of custodians, transfer agents and other agents; (11) costs of preparing share certificates; (12) expenses of setting in type and printing prospectuses and supplements thereto, statements of additional information and supplements thereto, reports and proxy materials for existing shareholders and costs of mailing such materials to existing shareholders; (13) any extraordinary expenses (including fees and disbursements of counsel) incurred by the fund; (14) fees, voluntary assessments and other expenses incurred in connection with membership in investment company organizations; (15) costs of mailing and tabulating proxies and costs of meetings of shareholders, the board and any committees thereof; (16) the cost of investment company literature and other publications provided to trustees and officers; (17) costs of mailing, stationery and communications equipment; (18) expenses incident to any dividend, withdrawal or redemption options; and (19) interest on borrowings of the fund.

UBS Select 100% US Treasury Institutional Fund, UBS Select 100% US Treasury Preferred Fund and UBS AM have entered into a written fee waiver/expense reimbursement agreement pursuant to which UBS AM is contractually obligated to waive its management fees and/or reimburse expenses so that the fund's ordinary total operating expenses through August 31, 2026 (excluding dividend expense, borrowing costs, and interest expense relating to short sales, and expenses attributable to investment in other investment companies, interest, taxes, brokerage commissions, expenses related to shareholders' meetings and extraordinary expenses) would not exceed 0.18% for UBS Select 100% US Treasury Institutional Fund and 0.14% for UBS Select 100% US Treasury Preferred Fund. Each fund has agreed to repay UBS AM for any waived fees/reimbursed expenses to the extent that it can do so over the following three fiscal years without causing the class expenses in any of those three years to exceed the lesser of any applicable expense limit that is in place for the fund (i) at the time of the waiver or reimbursement, or (ii) at the time of recoupment, and that UBS AM has not waived the right to do so. The fee waiver/expense reimbursement agreement may be terminated by the fund's board at any time and also will terminate automatically upon the expiration or termination of the fund's administration contract with UBS AM. Upon termination of the agreement, however, UBS AM's three year recoupment rights will survive.

UBS AM may voluntarily undertake to waive administration fees in the event that fund yields drop below a certain level. These additional undertakings are voluntary and not contractual and may be terminated at any time and are not subject to future recoupment.

UBS AM has entered into a Sub-Administration Agreement with State Street to provide accounting, portfolio valuation and certain sub-administrative services for the funds. UBS AM pays State Street for the services it provides under the Sub-Administration Agreement.

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During each of the fiscal years indicated, the funds listed above paid to UBS AM the following fees under its respective Administration Contract, after giving effect to the following amounts in fee waivers and/or other credits.

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| | | | |
|:---|:---|:---|:---|
|  | | **Fiscal years ended April 30,** | **Fiscal years ended April 30,** |
| | **2025** | **2024** | **2023** |
|  **UBS Select Treasury Institutional Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | $14644827 | $12037859 | $7304569 |
| Fee amount waived/expenses reimbursed | 0 | 0 |  |
| Other credits (Independent Trustee fees and expenses)<sup>1</sup> | 84674 | 75114 | 54920 |
|  **UBS Select Treasury Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | 8785582 | 7942160 | 6262675 |
| Fee amount waived/expenses reimbursed | 8884643 | 8033291 | 6342851 |
| Other credits (Independent Trustee fees and expenses)<sup>1</sup> | 99062 | 90266 | 78700 |
|  **UBS Prime Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | 3802273 | 2072366 | 857325 |
| Fee amount waived/expenses reimbursed | 3861225 | 2107006 | 879512 |
| Other credits (Independent Trustee fees and expenses)<sup>1</sup> | 58952 | 39423 | 22286 |
|  **UBS Prime Reserves Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | 9571868 | 5269845 | 2656035 |
| Fee amount waived/expenses reimbursed | 0 | 0 |  |
| Other credits (Independent Trustee fees and expenses)<sup>1</sup> | 67812 | 44115 | 27174 |
|  **UBS Select Government Institutional Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | 7205745 | 5292429 | 2646424 |
| Fee amount waived/expenses reimbursed | 0 | 0 |  |
| Other credits (Independent Trustee fees and expenses)<sup>1</sup> | 53227 | 43409 | 27215 |
|  **UBS Select Government Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | 6135037 | 4843374 | 2621536 |
| Fee amount waived/expenses reimbursed | 6210085 | 4912980 | 2662124 |
| Other credits (Independent Trustee fees and expenses)<sup>1</sup> | 75047 | 66100 | 40812 |
|  **UBS Select 100% US Treasury Institutional Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | 1752404 | 0 | — \* |
| Fee amount waived | 1442637 | 893 |  |
| Expense reimbursements | 75363 | 31478 | — \* |

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| | | | |
|:---|:---|:---|:---|
|  | | **Fiscal years ended April 30,** | **Fiscal years ended April 30,** |
| | **2025** | **2024** | **2023** |
|  **UBS Select 100% US Treasury Preferred Fund** |  |  |  |
| Net fee amount actually paid after waivers, reimbursements or credits | $99914 | $0 | $— \* |
| Fee amount waived | 2135943 | 1770 | — \* |
| Expense reimbursements | 65227 | 34779 | — \* |

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<sup>1</sup> UBS AM is contractually obligated to reduce its administration fee by an amount equal to the ordinary fees and expenses payable to the Independent Trustees by the fund. 

\* UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund commenced operations on March 13, 2024. Therefore, no fees were paid by each fund for the fiscal year ended April 30, 2023. 

Each fund has entered into a Service Agreement with State Street to provide certain regulatory support services to the fund, including: website posting of required information for money market funds and Form N-MFP and Form N-CR filing services. UBS AM pays State Street for the services it provides under the Service Agreement with respect to each fund except UBS Select 100% US Treasury Preferred Fund and UBS Select 100% US Treasury Institutional Fund. UBS Select 100% US Treasury Preferred Fund and UBS Select 100% US Treasury Institutional Fund pay State Street a fee at an agreed-upon rate for the services it provides under the Service Agreement. For the fiscal year ended April 30, 2025, UBS Select 100% US Treasury Preferred Fund and UBS Select 100% US Treasury Institutional Fund paid $0 and $0, respectively, in fees under the Service Agreement.

**Proxy voting policies.** The Trust board believes that the voting of proxies on securities held by a fund is an important element of the overall investment process. As such, the board has delegated the responsibility to vote such proxies to UBS AM. Following is a summary of UBS AM's proxy voting policy.

You may obtain information about a fund's proxy voting decisions, without charge, online on the following website: https://vds.issgovernance.com/vds/#/NDQx/FundFamily=322 under the appropriate "drop down" menu category on this Web page or on the EDGAR database on the SEC's website (http://www.sec.gov) for the most recent 12-month period ending June 30th for which an SEC filing has been made.

UBS AM's proxy voting policy is based on its belief that voting rights have economic value and should be treated accordingly. Good corporate governance should in the long term, lead towards better corporate performance and improved shareholder value. Generally, UBS AM expects the boards of directors of companies issuing securities held by its clients to act in the service of the shareholders, view themselves as stewards of the company, exercise good judgment and practice diligent oversight of the management of the company. A commitment to acting in as transparent a manner as possible is fundamental to good governance. While there is no absolute set of standards that determine appropriate corporate governance under all circumstances, and no set of values that will guarantee ethical board behavior, there are certain principles, which UBS AM considers are appropriate to protect the economic value of its clients' investments. UBS AM may delegate to an independent proxy voting and research service the authority to exercise the voting rights associated with certain client holdings. Any such delegation shall be made with the direction that the votes be exercised in accordance with UBS AM's proxy voting policy.

When UBS AM's view of a company's management is favorable, UBS AM generally supports current management initiatives. When UBS AM's view is that changes to the management structure would probably increase shareholder value, UBS AM may not support existing management proposals. If management's performance has been questionable, UBS AM may abstain or vote against specific proxy proposals. In general, UBS AM generally exercises voting rights in accordance with the following principles: (1) with respect to board structure, (a) an effective chair is key, (b) the roles of chair and chief executive officer should be separated, (c) board members should have appropriate and diverse experience and be capable of providing good judgment and diligent oversight of

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management, (d) the board should include executive and non-executive members; and (2) with respect to board responsibilities, (a) the whole board should be fully involved in endorsing strategy and in all major strategic decisions, (b) the non-executive directors should provide a challenging but positive environment for the executive directors and (c) the board should ensure that at all times (i) appropriate management succession plans are in place; (ii) the interests of executives and shareholders are aligned and the financial audit is independent and accurate; (iii) the brand and reputation of the company is protected and enhanced; (iv) a constructive dialogue with shareholders is encouraged; and (v) it receives all the information necessary to hold management accountable. UBS AM exercises its voting rights in accordance with overarching rationales outlined by its proxy voting policies and procedures that are based on the principles described above.

The proxy voting policy includes guidelines regarding consideration of environmental, social and corporate governance ("ESG") factors during the exercise of voting rights on behalf of UBS AM's clients, such as the fund. Underlying UBS AM's voting and ESG guidelines are two fundamental objectives: (1) acting in the best financial interest of clients and enhancing the long term value of their investments; and (2) promoting best practice in corporate governance and ensuring that portfolio companies are sustainable and successful.

UBS AM has implemented procedures designed to address a conflict of interest in voting a particular proxy proposal, which may arise as a result of its or its affiliates' client relationships, marketing efforts or banking, investment banking and broker/dealer activities. To address such conflicts, UBS AM has imposed information barriers between it and its affiliates who conduct banking, investment banking and broker/dealer activities and has implemented procedures to prevent business, sales and marketing issues from influencing its proxy votes. Whenever UBS AM becomes aware of a conflict with respect to a particular proxy, a vote normally will be cast in line with UBS AM's proxy voting policy. If it is identified that this action would not be in the best interests of UBS AM's clients, and under certain circumstances, the relevant internal UBS AM committee may be required to review and resolve the manner in which such proxy is voted.

**Principal underwriting arrangements.** UBS AM (US), 1285 Avenue of the Americas, New York, NY 10019 and One North Wacker Drive, Chicago, IL 60606, acts as the principal underwriter for each feeder fund pursuant to principal underwriting contracts with the Trust covering those funds (each a "Principal Underwriting Contract"). Each Principal Underwriting Contract requires UBS AM (US) to use its best efforts, consistent with its other business, to sell shares of the applicable funds. UBS AM (US) enters into selling agreements and dealer agreements with other broker-dealers (affiliated and unaffiliated) and with other institutions to authorize them to sell fund shares.

**All Funds.** UBS AM (US) may make cash and non-cash payments to affiliated and unaffiliated broker-dealers and other financial intermediaries (collectively, "Financial Intermediaries") that engage in selling efforts on behalf of a fund, subject to the internal policies and procedures of UBS AM (US). The source of such payments may come from UBS AM (US)'s own resources (including through transfers from affiliates). Payments made out of its own resources are often referred to as "revenue sharing." Revenue sharing payments generally are based on the value of fund shares sold as a result of such selling efforts although they could take other forms (such as, without limitation, ticket charges or "trail" fees for servicing shareholder accounts). Revenue sharing payments are negotiated by UBS AM (US) and may also be based on such other factors as the Financial Intermediary's ability to attract and retain assets, the quality and quantity of the services provided by the Financial Intermediary, the Financial Intermediary's relationship with UBS AM (US) or the reputation of the Financial Intermediary.

Revenue sharing payments are made by UBS AM (US) out of its own resources (and not out of fund assets). The value of a shareholder's investment in one of these funds and the return on that investment will be unaffected by these revenue sharing payments, which are in addition to amounts paid by a fund in connection with the distribution and shareholder servicing arrangements discussed above, if any. The source of revenue sharing payments may come from transfers from other UBS entities, such as UBS AM. UBS AM (US) may pay Financial Intermediaries a finder's fee for a variety of reasons, including (1) where UBS AM (US) is paying shareholder servicing fees or making other payments to a separate Financial Intermediary that makes shares available to others, (2) where the assets in an account reach a certain threshold or (3) where a Financial Intermediary provides marketing support

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or access to sales platforms or personnel. UBS AM (US) provides Financial Intermediaries with sales literature and advertising materials relating to the registered investment companies advised by UBS AM. UBS AM (US) also shares expenses with Financial Intermediaries for costs incurred in hosting seminars for employees and clients of Financial Intermediaries, subject to UBS AM (US)'s internal policies and procedures governing payments for such seminars. These seminars may take place at UBS AM (US)'s headquarters or other appropriate locations and may include reimbursement of travel expenses (*i.e.*, transportation, lodging and meals) of employees of Financial Intermediaries in connection with training and education seminars. Subject to UBS AM (US)'s internal policies and procedures, UBS AM (US) may provide any or all of the following to employees of Financial Intermediaries and their guest(s): (i) an occasional meal, a sporting event or theater ticket or other comparable entertainment; (ii) gifts of less than $100 per person per year; and/or (iii) UBS AM (US)'s promotional items of nominal value (golf balls, shirts, etc.). In addition, Financial Intermediaries may maintain omnibus accounts and/or have similar arrangements with UBS AM (US) and may be paid by UBS AM (US) for providing sub-transfer agency and other services.

To the extent permitted by applicable law, revenue sharing payments may take other forms or may be paid for other reasons. Investors should note that such payments may be more or less than the compensation on similar or other investments that your Financial Intermediary receives and may thus influence your Financial Intermediary to present or recommend a fund. You should ask your Financial Intermediary about any payment it receives from UBS AM (US) and any services provided.

**Securities lending.** Pursuant to an agreement between the funds and State Street, the funds may lend their securities through State Street as securities lending agent to certain qualified borrowers (the "Securities Lending Agreement"). As securities lending agent of the funds, State Street administers the funds' securities lending program. These services include arranging the securities loans with approved borrowers and collecting fees and rebates due to the funds. State Street also collects and maintains collateral intended to secure the obligations of each borrower and marks to market daily the value of loaned securities. If a borrower defaults on a loan, State Street is authorized to exercise contractual remedies on behalf of the funds and, pursuant to the terms of the Securities Lending Agreement, has agreed to indemnify the funds for certain losses, which exclude losses associated with collateral reinvestment. State Street may also, in its capacity as securities lending agent, invest cash received as collateral in pre-approved investments in accordance with the Securities Lending Agreement. State Street, in its capacity as securities lending agent of the funds, is authorized to engage a third party bank as a special "tri-party" custodian for securities lending arrangements and enter into a separate custodial undertaking with each applicable borrower under the funds' securities lending program. State Street maintains records of loans made and income derived therefrom and makes available such records that the funds deem necessary to monitor the securities lending program.

For the fiscal year ended April 30, 2025, the funds did not earn income or incur costs and expenses as a result of their securities lending activities.

Portfolio transactions

The funds purchase portfolio securities from dealers and underwriters as well as from issuers. Securities are usually traded on a net basis with dealers acting as principal for their own accounts without a stated commission. Prices paid to dealers in principal transactions generally include a "spread," which is the difference between the prices at which the dealer is willing to purchase and sell a specific security at the time. When securities are purchased directly from an issuer, no commissions or discounts are paid. When securities are purchased in underwritten offerings, they include a fixed amount of compensation to the underwriter.

For purchases or sales with broker-dealer firms that act as principal, UBS AM seeks best execution. Although UBS AM may receive certain research or execution services in connection with these transactions, it will not purchase

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securities at a higher price or sell securities at a lower price than would otherwise be paid if no weight was attributed to the services provided by the executing dealer. UBS AM may engage in agency transactions in over-the-counter securities in return for research and execution services. These transactions are entered into only pursuant to procedures that are designed to ensure that the transaction (including commissions) is at least as favorable as it would have been if effected directly with a market-maker that did not provide research or execution services.

Research services and information received from brokers or dealers are supplemental to UBS AM's own research efforts and, when utilized, are subject to internal analysis before being incorporated into their investment processes. Information and research services furnished by brokers or dealers through which or with which the funds effect securities transactions may be used by UBS AM in advising other funds or accounts and, conversely, research services furnished to UBS AM by brokers or dealers in connection with other funds or accounts may be used in advising the funds.

During the fiscal years ended April 30, 2025, 2024, and 2023, the funds did not pay brokerage commissions. The funds did not allocate any brokerage transactions for research, analysis, advice and similar services.

Investment decisions for the funds and for other investment accounts managed by UBS AM are made independently of one another in light of differing considerations for the various accounts. However, the same investment decision may occasionally be made for the funds and one or more of such accounts. In such cases, simultaneous transactions are inevitable. Purchases or sales are then averaged as to price and allocated between the funds and such other account(s) as to amount in a manner deemed equitable to the funds and such account(s). While in some cases this practice could have a detrimental effect upon the price or value of the security as far as the funds are concerned, or upon its ability to complete its entire order, in other cases it is believed that coordination and the ability to participate in volume transactions will be beneficial to the funds.

As of April 30, 2025 the corresponding master funds for UBS Select Government Institutional Fund, UBS Select Treasury Institutional Fund, UBS Select Government Preferred Fund, UBS Select Treasury Preferred Fund, UBS Prime Reserves Fund and UBS Prime Preferred Fund owned securities issued by their regular broker-dealers or entities that may be deemed affiliates of those regular broker-dealers (as defined in Rule 10b-1 under the Investment Company Act) as follows:

**Government Master Fund** 

(corresponding master fund for UBS Select Government Institutional Fund and UBS Select Government Preferred Fund)

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| | | | |
|:---|:---|:---|:---|
| **Issuer** | **Type of security** | **Value** | **Value** |
| J.P. Morgan Securities LLC | Repurchase agreements | | 2,700,000,000 |

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**Treasury Master Fund** 

(corresponding master fund for UBS Select Treasury Institutional Fund and UBS Select Treasury Preferred Fund)

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| | | | |
|:---|:---|:---|:---|
| **Issuer** | **Type of security** | **Value** | **Value** |
| Barclays Bank PLC | Repurchase agreements | | 1,000,000,000 |

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**Prime CNAV Master Fund** 

(corresponding master fund for UBS Prime Reserves Fund and UBS Prime Preferred Fund)

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| | | |
|:---|:---|:---|
| **Issuer** | **Type of security** | **Value** |
| Barclays Bank PLC | Repurchase agreements | $2200000000 |
| Barclays Bank PLC | Commercial paper | $465412823 |
| J.P. Morgan Securities LLC | Repurchase agreements | $279000000 |

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| | | |
|:---|:---|:---|
| **Issuer** | **Type of security** | **Value** |
| BofA Securities Inc. | Repurchase agreements | $265000000 |
| Mitsubishi Ufj Securities | Certificates of deposit | $424999498 |
| ABN AMRO Bank NV | Time deposits | $650000000 |
| BNP Paribas | Repurchase agreements | $225000000 |
| Bank of Montreal | Commercial paper | $30000000 |

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As of April 30, 2025, 100% US Treasury Master Fund (corresponding master fund for UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund) did not own securities issued by its regular broker-dealers or entities that may be deemed affiliates of those regular broker-dealers (as defined in Rule 10b-1 under the Investment Company Act).

Additional information regarding redemptions

**Additional redemption information.** The redemption price may be more or less than the shareholder's cost, depending on the market value of each fund's portfolio at the time, although the funds attempt to maintain a constant net asset value of $1.00 per share.

If conditions exist that make cash payments undesirable, each fund reserves the right to honor any request for redemption by making payment in whole or in part in securities chosen by the fund and valued in the same way as they would be valued for purposes of computing the fund's net asset value. If payment is made in securities, the shareholder may incur expenses in converting these securities into cash.

Valuation of shares

Each feeder fund uses its best efforts to maintain its net asset value at $1.00 per share using amortized cost-based pricing. UBS Prime Reserves Fund and UBS Prime Preferred Fund are available only to investors who qualify for investments in "retail" money market funds consistent with Rule 2a-7 under the Investment Company Act and related SEC staff guidance (*e.g.*, beneficial owners who are natural persons). The funds' net asset values per share are typically determined by the funds' custodian, State Street.

Each master fund values its portfolio securities in accordance with the amortized cost method of valuation under Rule 2a-7 (the "Rule") under the Investment Company Act. To use amortized cost to value its portfolio securities, a master fund must adhere to certain conditions under the Rule relating to its investments, some of which are discussed in this SAI. Amortized cost is an approximation of market value of an instrument, whereby the difference between its acquisition cost and value at maturity is amortized on a straight-line basis over the remaining life of the instrument. The effect of changes in the market value of a security as a result of fluctuating interest rates is not taken into account, and thus the amortized cost method of valuation may result in the value of a security being higher or lower than its actual market value. If a large number of redemptions take place at a time when interest rates have increased, the master funds might have to sell portfolio securities prior to maturity and at a price that might not be desirable.

With respect to each master fund, the master funds' board has established procedures ("Procedures") for the purpose of stabilizing the value of such a master fund's net assets within 1/2 of 1% of the value determined based on amortized cost. The Procedures include a review of the extent of any deviation of net asset value, based on available market quotations. If that deviation exceeds 1/2 of 1% for a master fund, the board will promptly consider whether any action should be initiated to eliminate or reduce material dilution or other unfair results to

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shareholders. Such action may include redeeming interests in kind, selling portfolio securities prior to maturity, reducing or withholding dividends and utilizing a net asset value as determined by using available market quotations. In addition, if the master funds' board determines that a fund can no longer maintain a constant net asset value of $1.00 per share, the fund may, as part of converting to a market based net asset value, take steps to: (i) temporarily suspend the offering of fund shares; (ii) delay the payment of redemption proceeds for up to seven days, as permitted by the Investment Company Act; and (iii) price its shares once a day at the last current valuation time (e.g., 5:00 p.m., Eastern time, for UBS Select Treasury Institutional Fund, UBS Select Treasury Preferred Fund, UBS Prime Reserves Fund, UBS Prime Preferred Fund, UBS Select Government Institutional Fund and UBS Select Government Preferred Fund; and 2:30 p.m., Eastern time, for UBS Select 100% US Treasury Institutional Fund and UBS Select 100% US Treasury Preferred Fund).

The board may also reduce the number of shares outstanding on a pro rata basis through a reverse stock split to the extent permissible by applicable law and the Trust's organizational documents. The board may consider this action if a fund has a negative gross yield as a result of negative interest rates to maintain a fund's $1.00 net asset value per share. The use of such measures is subject to certain determinations by the fund's board and disclosure requirements, and may have tax implications for the fund and its shareholders. Consistent with SEC staff guidance, a reverse stock split may trigger a filing with the SEC on Form N-CR.

Rule 2a-5 ("Rule 2a-5") under the Investment Company Act provides that a market quotation is readily available only when that quotation is a quoted price (unadjusted) in active markets for identical investments that the fund can access at the measurement date, provided that a quotation will not be readily available if it is not reliable. Securities for which market quotations are not readily available must be valued at fair value as determined in good faith by or under the direction of the board or its designee. The board designated UBS AM as the valuation designee pursuant to Rule 2a-5 to perform fair value determinations for the funds. 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. Valuing securities at fair value involves greater reliance on judgment than valuing securities that have readily available market quotations. Accordingly, there can be no assurance that the determination of a security's fair value in accordance with a fund's valuation procedures will in fact approximate the price at which a fund could sell that security at that time.

Each master fund will maintain a dollar-weighted average portfolio maturity of 60 days or less and a dollar-weighted average life for its portfolio of 120 days or less, will not purchase any instrument having, or deemed to have, a remaining maturity of more than 397 days, will limit portfolio investments, including repurchase agreements, to those US-dollar denominated instruments that are of high quality under the Rule and that UBS AM, acting pursuant to the Procedures, determines present minimal credit risks, and will comply with certain reporting and recordkeeping procedures. If amortized cost ceases to represent fair value for those master funds using that method, UBS AM will take appropriate action as the funds' valuation designee pursuant to Rule 2a-5 under the Investment Company Act.

In determining the approximate market value of portfolio investments, the master funds may employ outside organizations, which may use a matrix or formula method that takes into consideration market indices, matrices, yield curves and other specific adjustments. This may result in the securities being valued at a price different from the price that would have been determined had the matrix or formula method not been used. Other assets, if any, are valued at fair value as determined in good faith by or under the direction of UBS AM as the funds' valuation designee.

The UBS AM website noted above also features additional information for each of the funds, such as historical performance information (e.g., yields) and certain additional portfolio statistics.

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Taxes

**Qualification as a regulated investment company.** Each fund intends to continue to qualify for treatment as a regulated investment company ("RIC") under Subchapter M of the Internal Revenue Code. To so qualify, each feeder fund must distribute to its shareholders in each taxable year an amount at least equal to the sum of 90% of its investment company taxable income (consisting generally of net investment income and net short-term capital gain, if any, determined without regard to any deduction for dividends paid) and any net tax-exempt income and must meet several additional requirements. Among these requirements are the following: (1) the feeder fund must derive at least 90% of its gross income each taxable year from dividends, interest, payments with respect to securities loans, gains from the sale or other disposition of securities, net income derived from an interest in a qualified publicly-traded partnership and certain other income; (2) at the close of each quarter of the feeder fund's taxable year, at least 50% of the value of its total assets must be represented by cash and cash items, US government securities, securities of other RICs and other securities that are limited, in respect of any one issuer, to an amount that does not exceed 5% of the value of the feeder fund's total assets nor 10% of the voting securities of such issuer; and (3) at the close of each quarter of the feeder fund's taxable year, not more than 25% of the value of its total assets may be invested in securities (other than US government securities or the securities of other RICs) of any one issuer, in two or more issuers that the fund controls and which are engaged in the same or similar trades or businesses or of one or more qualified publicly traded partnerships.

By qualifying for treatment as a RIC, the feeder fund (but not its shareholders) will be relieved of federal income tax on the portion of its investment company taxable income and net capital gain that it distributes to shareholders, provided that it distributes an amount at least equal to 90% of its investment company taxable income and net tax-exempt income for the taxable year. If the feeder fund failed to qualify for treatment as a RIC for any taxable year, (1) it would be taxed as an ordinary corporation on the full amount of its taxable income for that year without being able to deduct the distributions it makes to its shareholders and (2) the shareholders would treat all those distributions (including distributions that would otherwise be "exempt-interest dividends,") as dividends (that would generally be taxed as ordinary income) to the extent of the fund's earnings and profits. In addition, the feeder fund could be required to recognize unrealized gains, pay substantial taxes and interest, and make substantial distributions before requalifying for RIC treatment.

**Taxes on fund distributions and redemptions.** Distributions of investment company taxable income are taxable to you, whether paid in cash or reinvested in fund shares. Distributions of net investment income received by each fund from investments in debt securities and any net realized short-term capital gains distributed by each fund will be taxable to shareholders as ordinary income (except to the extent that such dividends are reported as exempt-interest dividends) and will not be eligible for the dividends-received deduction for corporations. Due to their investment strategies, each feeder fund will not typically derive material amounts of net long-term capital gains.

Although current tax law generally provides for a minimum tax rate for individual taxpayers of 15% or 20% (depending on whether the individual's income exceeds certain threshold amounts) on certain qualifying dividend income, distributions from funds such as these feeder funds investing primarily in bonds and other debt instruments via the master funds will not generally qualify for the lower tax rates.

An additional 3.8% Medicare tax is imposed on certain net investment income (including ordinary dividends and capital gain distributions received from a 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.

Certain distributions reported by a fund as Section 163(j) interest dividends under the Internal Revenue Code may be treated as interest income by shareholders for purposes of the tax rules applicable to interest expense limitations

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under Internal Revenue Code Section 163(j). Such treatment by the shareholder is generally subject to holding period requirements and other potential limitations, although the holding period requirements are generally not applicable to dividends declared by money market funds and certain other funds that declare dividends daily and pay such dividends on a monthly or more frequent basis. The amount that a fund is eligible to report as a Section 163(j) dividend for a tax year is generally limited to the excess of a fund's business interest income over the sum of a fund's (i) business interest expense and (ii) other deductions properly allocable to a fund's business interest income.

Taxable distributions to non-US shareholders will generally be subject to a 30% withholding tax (or lower applicable treaty rate). Distributions to non-residents 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. However, certain properly reported distributions paid by the funds 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 funds properly report 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 funds are a 10-percent shareholder or is contingent interest, and (4) any interest-related dividend from another regulated investment company. 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 funds' transfer agent, or a financial intermediary through whom an investor owns fund shares, may withhold US federal income tax on an entire dividend if a fund reports that less than all of the dividend is an interest-related dividend. Similarly, it is possible that a financial intermediary may withhold US federal income tax on a dividend even if a fund reports that all of the dividend is an interest-related dividend. In such scenarios, tax withheld by the transfer agent or intermediary would generally be refundable, but would generally require the non-US shareholder to file a US income tax return to claim the refund.

Each 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 funds to enable the funds 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 funds.

Non-US shareholders may also be subject to US estate tax with respect to their shares of a fund.

Each fund will be subject to a nondeductible 4% excise tax to the extent it fails to distribute by the end of any calendar year substantially all its ordinary (*i.e.*, taxable) income (taking into account certain deferrals and elections) for that year and any capital gain net income for the one-year period ending October 31 of that year, plus certain other amounts.

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. However, a liquidity fee imposed by a fund will reduce the amount you will receive upon the redemption of your shares, and will decrease the amount of any capital gain or increase the amount of any capital loss you will recognize from such redemption. There is some degree of uncertainty with respect to the tax treatment of liquidity fees received by money market funds, and such tax treatment may be the subject of future guidance issued by the Internal Revenue Service ("IRS"). If a fund receives liquidity fees, it will consider the appropriate tax treatment of such fees to the fund at such time.

Further, with respect to any capital gain or loss recognized on the sale or exchange of shares of a fund, unless a shareholder chooses to adopt a simplified "NAV method" of accounting (described below), such capital gain or loss

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generally will be treated either as short-term if you held your shares as capital assets for one year or less, or long-term if you held your shares longer. Other restrictions may be applicable with respect to losses on the sale of fund shares.

Alternatively, if a shareholder elects to adopt the simplified "NAV method" of accounting, rather than compute gain or loss on every taxable sale or other disposition of shares of a fund as described above, a shareholder would determine gain or loss based on the change in the aggregate value of fund shares during a computation period (such as the shareholder's taxable year), reduced by the shareholder's net investment (i.e., purchases minus sales) in those fund shares during the computation period. Under the simplified "NAV method," any resulting capital gain or loss would be reportable on a net basis and would generally be treated as a short-term capital gain or loss.

Please be advised that abandoned or unclaimed property laws for certain states (to which your account may be subject) require financial organizations to transfer (escheat) unclaimed property (including shares of a fund) to the appropriate state if no activity occurs in an account for a period of time specified by state law. For IRA accounts escheated to a state under these abandoned property laws, the escheatment will generally be treated as a taxable distribution to you; federal and any applicable state income tax will be withheld. This may apply to your Roth IRA as well.

The foregoing is a general, abbreviated summary of certain provisions of the federal tax laws currently in effect as they directly govern the taxation of shareholders of each fund. These provisions are subject to change by legislative or administrative action, and any such change may be retroactive with respect to fund transactions. Shareholders are advised to consult with their own tax advisers for more detailed information concerning federal tax matters.

**Tax treatment of master funds.** Each master fund will be treated as a non-publicly traded partnership for federal income tax purposes rather than as a RIC or a corporation under the Internal Revenue Code. Under the rules applicable to a non-publicly traded partnership, a proportionate share of any interest, dividends, gains and losses of a corresponding master fund will be deemed to have been realized (*i.e.*, "passed through") to its interest holders (including a fund) regardless of whether any amounts are actually distributed by the master fund. Each interest holder in a master fund will be taxed on such proportionate share, as determined in accordance with the governing instruments of the master fund, the Internal Revenue Code and applicable regulations, in determining such interest holder's federal income tax liability. Therefore, to the extent that a master fund were to accrue but not distribute any income or gains, a fund investing in the master fund would be deemed to have realized its proportionate share of such income or gains without receipt of any corresponding distribution. However, each of the master funds will seek to minimize recognition by its interestholders (including the funds) of income and gains without a corresponding distribution. Furthermore, each master fund's assets, income and distributions will be managed in such a way that an interestholder in a master fund will be able to continue to qualify as a RIC by investing its assets through the master fund.

**Backup withholding.** Each fund is required to withhold 24% of all dividends payable to individuals and certain other non-corporate shareholders who do not provide the fund or UBS Financial Services Inc. with a correct taxpayer identification number or who are otherwise subject to backup withholding.

Potential conflicts of interest

**Activities of UBS Asset Management (Americas) LLC and its affiliates (collectively, "UBS Asset Management"), UBS Securities LLC and UBS Financial Services Inc. and their affiliates (collectively, "UBS") and other accounts managed by UBS** 

UBS Asset Management is a large asset management firm with approximately $2.0 trillion in assets under management worldwide as of September 30, 2025.<sup>1</sup> UBS Asset Management offers investment capabilities and investment styles across

<sup>1</sup> UBS AM managed approximately $590 billion as of September 30, 2025. 

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all major traditional and alternative asset classes, including equity, fixed income, currency, hedge fund, real estate, infrastructure and private equity investment capabilities that can also be combined in multi-asset strategies. UBS Asset Management has nine main hubs globally: Chicago, Hong Kong, London, New York, Shanghai, Singapore, Sydney, Tokyo and Zurich.

UBS is a worldwide full-service investment banking, broker-dealer, asset management and financial services organization. As a result, UBS Asset Management and UBS (including, for these purposes, their directors, partners, officers and employees) worldwide, including the entities and personnel who may be involved in the investment activities and business operations of the funds, are engaged in businesses and have interests other than that of managing the funds. These activities and interests include potential multiple advisory, transactional, financial, consultative, and other interests in transactions, companies, securities and other instruments that may be engaged in, purchased or sold by the funds. This section sets forth considerations of which investors in the funds should be aware, and which may cause conflicts of interest on the part of UBS and UBS Asset Management that could disadvantage the funds. To address these potential conflicts, UBS and UBS Asset Management have established various policies and procedures that are reasonably designed to detect and prevent these potential conflicts of interest and prevent the funds from being disadvantaged.

Prospective investors should carefully review the following, which more fully describes these and other potential conflicts of interest presented by UBS Asset Management's and UBS' other businesses and interests.

**Potential conflicts relating to portfolio decisions, the sale of fund shares and the allocation of investment opportunities UBS' other activities may have an impact on the funds.** UBS Asset Management makes decisions for the funds in accordance with its obligations as investment advisor to the funds. However, UBS' other activities may, at the same time, have a negative impact on the funds. As a result of the various activities and interests of UBS, it is likely that the funds will have multiple business relationships with, engage in transactions with, make voting decisions with respect to, or obtain services from UBS and other entities for which UBS performs or seeks to perform investment banking or other services. It is also likely that the funds will undertake transactions in securities in which UBS makes a market or otherwise has other direct or indirect interests.

UBS conducts extensive broker-dealer, banking and other activities around the world and provides investment banking, broker-dealer, prime brokerage, administrative and other services to clients which may involve markets and securities in which the funds invest. These activities will give UBS broad access to the current status of certain markets and investments. As a result of the activities described in this paragraph and the access and knowledge arising from those activities, parts of UBS may be in possession of information in respect of markets and investments, which, if known to UBS Asset Management, might cause UBS Asset Management to seek to dispose of, retain or increase interests in investments held by a fund or acquire certain positions on behalf of a fund. UBS will be under no duty to make any such information available to the funds or personnel of UBS Asset Management making investment decisions on behalf of the funds and maintains information barriers designed to prevent the misuse of such information. In general, personnel of UBS Asset Management making investment decisions will make decisions based solely upon information known by such decision makers without regard to information known by other UBS personnel.

In conformance with a fund's investment objective and subject to compliance with applicable law, UBS Asset Management may purchase securities for a fund during an underwriting or other offering of securities in which a broker/dealer affiliate acts as a manager, co-manager, underwriter or placement agent, or receives a benefit in the form of management, underwriting, or other fees. Affiliates of UBS Asset Management may act in other capacities in such offerings for which a fee, compensation, or other benefit will be received. From time to time, affiliates of UBS Asset Management will be current investors in companies engaged in an offering of securities which UBS Asset Management may purchase on behalf of its clients. Such purchases may provide a direct or indirect benefit to UBS Asset Management affiliates acting as a selling shareholder. UBS Asset Management may also participate in structured fixed income offerings of securities in which a related person may serve as trustee, depositor, originator,

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service agent or other service provider in which fees will be paid to such related person. Further, a related person may act as originator and/or servicing agent of loans or receivables for a structured fixed income offering in which UBS Asset Management may invest fund assets. Participation in such offering may directly or indirectly relieve financial obligations of related persons.

UBS Asset Management may purchase or sell, or recommend for purchase or sale, for its investment advisory clients securities of companies: (i) with respect to which its affiliates act as an investment banker or financial adviser; (ii) with which its affiliates have other confidential relationships; (iii) in which its affiliates maintain a position or (iv) for which its affiliates make a market; or in which it or its officers, directors or employees or those of its affiliates own securities or otherwise have an interest. Except to the extent prohibited by law or regulation or by client instruction, UBS Asset Management may recommend to its clients, or purchase for its clients, securities of issuers in which UBS has an interest as described in this paragraph.

**UBS' financial and other interests and relationships may incentivize UBS to promote the sale of fund shares.** UBS, its personnel and other financial service providers, have interests in promoting sales of the funds. UBS Asset Management may also make cash and non-cash payments to banks, broker-dealers, insurance companies, financial planning firms and other financial intermediaries, that sell shares of the funds, subject to UBS Asset Management's internal policies and procedures. The source of such payments may come from sales charges on such shares, 12b-1 fees collected from the fund and/or from the underwriter's own resources (including through transfers from affiliates). Payments made out of the underwriter's own resources are often referred to as "revenue sharing." Please read the section entitled "Investment advisory, administration and principal underwriting arrangements" for more information.

With respect to both UBS and its personnel, the remuneration and profitability relating to services to and sales of the funds or other products may be greater than the remuneration and profitability relating to services to and sales of other products that might be provided or offered by UBS or other third parties. UBS and its sales personnel may directly or indirectly receive a portion of the fees and commissions charged to the funds or their shareholders. UBS and its advisory or other personnel may also benefit from increased amounts of assets under management. Fees and commissions charged to the funds may also be higher than for other products or services, and the remuneration and profitability to UBS and such personnel resulting from transactions on behalf of or management of the funds may be greater than the remuneration and profitability resulting from similar transactions for other funds or products.

UBS also may have relationships with, and purchase, or distribute or sell, services or products from or to, distributors, consultants and others who recommend the funds, or who engage in transactions with or for the funds. For example, UBS regularly participates in industry and consultant sponsored conferences and may purchase educational, data or other services from consultants or other third parties that it deems to be of value to its personnel and its business. The products and services purchased from consultants may include, but are not limited to, those that help UBS understand the consultant's points of view on the investment management process. Consultants and other parties that provide consulting or other services to potential investors in the funds may receive fees from UBS or the funds in connection with the distribution of shares in the funds or other UBS products. For example, UBS may enter into revenue or fee sharing arrangements with consultants, service providers, and other intermediaries relating to investments in mutual funds, collective trusts, or other products or services offered or managed by UBS Asset Management. UBS may also pay a fee for membership in industry-wide or state and municipal organizations or otherwise help sponsor conferences and educational forums for investment industry participants including, but not limited to, trustees, fiduciaries, consultants, administrators, state and municipal personnel and other clients. UBS' membership in such organizations allows UBS to participate in these conferences and educational forums and helps UBS interact with conference participants and to develop an understanding of the points of view and challenges of the conference participants. In addition, UBS' personnel, including employees of UBS, may have board, advisory, brokerage or other relationships with issuers, distributors, consultants and others that may have investments in the funds or that may recommend investments in the funds. In addition, UBS, including UBS Asset Management, may make charitable contributions to institutions, including those that have

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relationships with clients or personnel of clients. UBS' personnel may also make political contributions. As a result of the relationships and arrangements described in this paragraph, consultants, distributors and other parties may have conflicts associated with their promotion of the funds or other dealings with the funds that create incentives for them to promote the funds or certain portfolio transactions.

To the extent permitted by applicable law, UBS Asset Management may make payments to authorized dealers and other financial intermediaries ("Intermediaries") from time to time to promote the funds. The additional payments by UBS Asset Management may also compensate Intermediaries for subaccounting, administrative and/or shareholder processing services that are in addition to the fees paid for these or similar services by the funds. Payments made by UBS Asset Management may vary between different Intermediaries. Please read the section entitled "Investment advisory, administration and principal underwriting arrangements" for more information.

**Potential conflicts relating to the allocation of investment opportunities among the funds and other UBS accounts.** UBS Asset Management provides investment advisory services to certain accounts, including through model based programs, UBS Asset Management may have investment discretion ("Discretionary Accounts") or may not have investment discretion ("Non-Discretionary Accounts"). In the case of Non-Discretionary Accounts, the account will typically be notified of recommended changes to a model simultaneously with the Discretionary Accounts. With respect to the funds, UBS Asset Management may follow a strategy that is expected to be similar over time to that utilized by those accounts. The funds and the Non-Discretionary Account clients are subject to independent management and, given the independence in the implementation of advice to these accounts, there can be no assurance that such investment advice will be implemented simultaneously. Neither UBS Asset Management nor its affiliates will know when advice issued has been executed (if at all) and, if so, to what extent. Therefore, it is possible that prior execution by Non-Discretionary Accounts could adversely affect the prices and availability of the securities, currencies and instruments in which a fund invests.

**Other potential conflicts relating to the management of the funds by UBS Asset Management** 

**Potential restrictions and issues relating to information held by UBS.** From time to time and subject to UBS Asset Management's policies and procedures regarding information barriers, UBS Asset Management may consult with personnel in other areas of UBS, or with persons unaffiliated with UBS. The performance by such persons of obligations related to their consultation with personnel of UBS Asset Management could conflict with their areas of primary responsibility within UBS or elsewhere. There will be no obligation on the part of such persons to make available for use by the funds any information or strategies known to them or developed in connection with their own client, proprietary or other activities. In addition, UBS will be under no obligation to make available any research or analysis prior to its public dissemination.

In connection with its management of the funds, UBS Asset Management may have access to certain fundamental analysis and proprietary technical models developed by UBS Asset Management or its affiliates (including UBS). UBS Asset Management will not be under any obligation, however, to effect transactions on behalf of the funds in accordance with such analysis and models. In addition, neither UBS Asset Management nor any of its affiliates (including UBS) will have any obligation to make available any information regarding their proprietary activities or strategies, or the activities or strategies used for other accounts managed by them, for the benefit of the management of the funds, and it is not anticipated that UBS Asset Management will have access to such information for the purpose of managing the funds. The proprietary activities or portfolio strategies of UBS Asset Management and its affiliates (including UBS) or the activities or strategies used for accounts managed by them or other client accounts could conflict with the transactions and strategies employed by UBS Asset Management, and have adverse effects on the funds.

**Potential conflicts relating to UBS' and UBS Asset Management's proprietary activities and activities on behalf of other accounts.** Transactions undertaken by UBS or client accounts managed by UBS ("Client Accounts") may adversely impact the funds. UBS and one or more Client Accounts may buy or sell positions while a

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fund is undertaking the same or a differing, including potentially opposite, strategy, which could disadvantage the fund. For example, an equity fund (but not these money market funds) may establish a short position in a security and UBS or other Client Accounts may buy that same security. The subsequent purchase may result in an increase of the price of the underlying position in the short sale exposure of the equity fund and such increase in price would be to the equity fund's detriment. Conversely, the equity fund may buy a security, and UBS or Client Accounts may establish a short position in that same security. The subsequent short sale may result in impairment of the price of the security which the equity fund holds. Conflicts may also arise because portfolio decisions regarding the equity fund may benefit UBS or other Client Accounts. For example, the sale of a long position or establishment of a short position by the equity fund may impair the price of the same security sold short by (and therefore benefit) UBS or other Client Accounts, and the purchase of a security or covering of a short position in a security by the equity fund may increase the price of the same security held by (and therefore benefit) UBS or other Client Accounts.

The directors, officers and employees of UBS and UBS Asset Management may buy and sell securities or other investments for their own accounts or for seed capital accounts (including through investment funds managed by UBS and UBS Asset Management). As a result of differing trading and investment strategies or constraints, positions may be taken by directors, officers and employees that are the same, different from or made at different times than positions taken for a fund. To reduce the possibility that a fund will be materially adversely affected by the personal or proprietary trading described above, the funds, UBS and UBS Asset Management have established policies and procedures that restrict securities trading in the personal accounts of investment professionals and others who normally come into possession of information regarding the funds' portfolio transactions.

UBS Asset Management's affiliates have direct or indirect interests in electronic communication networks and alternative trading systems (collectively "ECNs"). UBS Asset Management, in accordance with its fiduciary obligation to seek to obtain best execution, may execute client trades through ECNs in which its related persons have, or may acquire, an interest. A related person may receive compensation based upon its ownership percentage in relation to the transaction fees charged by the ECNs. UBS Asset Management will execute through an ECN in which a related person has an interest only in situations where it reasonably believes such transactions will be in the best interests of its clients and the requirements of applicable law have been satisfied.

In accordance with Section 11(a) of the Securities Exchange Act of 1934, as amended, and the rules thereunder, UBS Asset Management's affiliates may effect transactions for funds or advisory client accounts on a national securities exchange of which an affiliate is an equity owner and/or a member and may retain compensation in connection with those transactions.

**Gifts and entertainment.** From time to time, directors, officers and employees of UBS and UBS Asset Management may receive gifts and/or entertainment from clients, intermediaries, or service providers to the funds, UBS and UBS Asset Management, which could have the appearance of affecting or may potentially affect the judgment of the directors, officers and employees or the manner in which they conduct business on behalf of the funds, UBS and UBS Asset Management. To reduce the appearance of impropriety and the possibility that the funds may be materially adversely affected by such gifts and entertainment, UBS and UBS Asset Management have established policies and procedures that restrict the receipt of gifts and entertainment from clients, intermediaries, or service providers to the funds, UBS and UBS Asset Management.

**UBS may in-source or outsource.** Subject to applicable law, UBS, including UBS Asset Management, may from time to time and without notice to investors in-source or outsource certain processes or functions in connection with a variety of services that it provides to the funds in its administrative or other capacities. Such in-sourcing or outsourcing may give rise to additional conflicts of interest.

**Selection of brokers and dealers and commission rates** 

While UBS Asset Management selects brokers primarily on the basis of the execution capabilities, UBS Asset Management, in its discretion, may cause a client to pay a commission to brokers or dealers for effecting a

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transaction for that client in excess of the amount another broker or dealer would have charged for effecting that transaction. This may be done when UBS Asset Management has determined in good faith that the commission is reasonable in relation to the value of the execution, brokerage and/or research services provided by the broker. UBS Asset Management's arrangements for the receipt of research services from brokers may create conflicts of interest, in that UBS Asset Management has an incentive to choose a broker or dealer that provides research services, instead of one that charges a lower commission rate but does not provide any research.

UBS Asset Management does not allocate the relative costs or benefits of research received from brokers or dealers among clients because UBS Asset Management believes that the research received is, in the aggregate, of assistance in fulfilling UBS Asset Management's overall responsibilities to clients. The research may be used in connection with the management of accounts other than those for which trades are executed by the brokers or dealers providing the research. UBS Asset Management may receive a variety of research services and information on many topics, which UBS Asset Management can use in connection with its management responsibilities with respect to the various accounts over which it exercises investment discretion or otherwise provides investment advice. These topics include: issuers, industries, securities, economic factors and trends, portfolio strategy, the performance of accounts, statistical information, market data, earnings estimates, credit analysis, pricing, risk measurement analysis, and other information that may affect US or foreign economies, security prices, or management of the portfolio.

The research services may include written reports, pricing and appraisal services, market data services, analysis of issues raised in proxy statements, educational seminars, subscriptions to trade journals, portfolio attribution and monitoring services and computer software and access charges which are directly related to investment research. Research services may be received in the form of written reports, online services, telephone contacts and personal meetings with security analysts, economists, corporate and industry spokespersons, investment consultants and government representatives. Research services are either provided directly by broker-dealers or generated by third parties and are provided by the brokerage firm to which the commissions are paid including commission sharing arrangements.

Certain services may be mixed use, or used for research purposes as well as other purposes. Payment for these services is made as follows: the portion allocated to research is paid for through commissions, and the portion allocated to other purposes is paid for by UBS Asset Management. This allocation is determined by UBS Asset Management's Best Execution and Trading Committee in good faith and based on objective criteria, to the extent available, of the amounts used for research and non-research purposes; however, the decision regarding what amounts are paid by UBS Asset Management versus paid by clients through commissions presents a conflict of interest. Research services received from brokers and dealers may be supplemental to UBS Asset Management's own research efforts and, when utilized, are subject to internal analysis before being incorporated into UBS Asset Management's investment process. As a practical matter, it would not be possible for UBS Asset Management to generate all of the information presently provided by brokers and dealers.

UBS Asset Management may receive in-house or proprietary research from dealers that execute trades on a principal basis for its clients. The research received will be of the type described above, excluding third-party research services.

**Potential regulatory restrictions on investment advisor activity** 

From time to time, the activities of the funds may be restricted because of regulatory requirements applicable to UBS and/or its internal policies designed to comply with, limit the applicability of, or otherwise relate to such requirements. A client not advised by UBS would not be subject to some of those considerations. There may be periods when UBS Asset Management may not initiate or recommend certain types of transactions, or may otherwise restrict or limit its advice with respect to certain securities or instruments issued by or related to companies for which UBS is performing investment banking, market making or other services or has proprietary positions or otherwise has come into possession of material inside information. For example, when UBS is engaged in an underwriting or other distribution of securities of, or advisory services for, a company, the funds may be prohibited from or limited in purchasing or selling securities of that company. Similar situations could arise if UBS personnel serve as directors of companies the securities of which a fund wishes to purchase or sell. The larger UBS

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Asset Management's investment advisory business and UBS' businesses, the larger the potential that these restricted list policies will impact investment transactions. However, if permitted by applicable law, a fund may purchase securities or instruments that are issued by such companies or are the subject of an underwriting, distribution, or advisory assignment by UBS, or in cases in which UBS personnel are directors or officers of the issuer.

The investment activities of UBS for its proprietary accounts and for Client Accounts may also limit the investment strategies and rights of the funds. For example, in regulated industries, in certain emerging or international markets, in corporate and regulatory ownership definitions, and in certain futures and derivative transactions, there may be limits on the aggregate amount of investment by affiliated investors that may not be exceeded without the grant of a license or other regulatory or corporate consent or, if exceeded, may cause UBS, the funds or other Client Accounts to suffer disadvantages or business restrictions. If certain aggregate ownership thresholds are reached or certain transactions undertaken, the ability of UBS Asset Management on behalf of a fund to purchase or dispose of investments, or exercise rights or undertake business transactions, may be restricted by regulation or otherwise impaired. As a result, UBS Asset Management on behalf of a fund may limit purchases, sell existing investments, or otherwise restrict or limit the exercise of rights (including voting rights) when UBS Asset Management, in its sole discretion, deems it appropriate.

UBS Asset Management and its affiliates, including, without limitation, UBS and its advisory affiliates, have proprietary interests in, and may manage or advise with respect to, accounts or funds (including separate accounts, other funds and collective investment vehicles) that have investment objectives similar to those of the funds and/or that engage in transactions in the same types of securities, currencies and instruments as the funds. UBS and its affiliates are also major participants in the global currency, equities, swap and fixed income markets, in each case both on a proprietary basis and for the accounts of customers. As such, UBS and its affiliates may be actively engaged in transactions in the same securities, currencies, and instruments in which the funds invest. Such activities could affect the prices and availability of the securities, currencies, and instruments in which the funds invest, which could have an adverse impact on a fund's performance. Such transactions, particularly in respect of most proprietary accounts or client accounts, will be executed independently of the funds' transactions and thus at prices or rates that may be more or less favorable than those obtained by the funds. UBS Asset Management has developed policies and procedures consistent with regulatory requirements that provide that it will allocate investment opportunities and make purchase and sale decisions among the funds and other client accounts in a manner that it considers, in its sole discretion and consistent with its fiduciary obligation to each account, to be reasonable. Allocations may be based on numerous factors and may not always be pro rata based. Thus, this system may adversely affect the size or price of the assets purchased or sold for the funds.

The results of the funds' investment activities may differ significantly from the results achieved by UBS Asset Management and its affiliates for their proprietary accounts or other accounts (including investment companies or collective investment vehicles) managed or advised by them. It is possible that UBS Asset Management and its affiliates and such other accounts will achieve investment results that are substantially more or less favorable than the results achieved by the funds. Moreover, it is possible that a fund will sustain losses during periods in which UBS Asset Management and its affiliates achieve significant profits on their trading for proprietary or other accounts. The opposite result is also possible.

The investment activities of UBS Asset Management and its affiliates for their proprietary accounts and accounts under their management may also limit the investment opportunities for a fund in certain emerging and other markets in which limitations are imposed upon the amount of investment, in the aggregate or in individual issuers, by affiliated foreign investors.

From time to time, the funds' activities may also be restricted because of regulatory restrictions applicable to UBS Asset Management and its affiliates, and/or their internal policies designed to comply with such restrictions. As a result, there may be periods, for example, when UBS Asset Management, and/or its affiliates, will not initiate or recommend certain types of transactions in certain securities or instruments with respect to which UBS Asset

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Management and/or its affiliates are performing services or when position limits have been reached where such securities or instruments otherwise would have been permissible investments for the funds. Additionally, the funds or certain accounts may be licensed to trade securities or engage in transactions in certain jurisdictions while other funds and accounts are not licensed.

In addition, certain officers and certain employees of UBS Asset Management are also officers or employees of UBS, or its affiliated entities. As a result, the performance by these officers and employees of their obligations to such other entities may be a consideration of which investors in the funds should be aware.

UBS Asset Management may enter into transactions and invest in securities, instruments and currencies on behalf of a fund where customers of UBS or, to the extent permitted by the SEC, UBS itself, serves as the counterparty, principal or issuer. In such cases, such party's interests in the transaction will be adverse to the interests of the fund, and such party may have no incentive to assure that the fund obtains the best possible prices or terms in connection with the transaction. In addition, the purchase, holding and sale of such investments by the fund may enhance the profitability of UBS Asset Management and/or UBS. UBS and its affiliates may also create, write or issue derivative instruments for customers of UBS or its affiliates, the underlying securities, currencies or instruments of which may be those in which a fund invests or which may be based on the performance of a fund. The funds may, subject to applicable law, purchase investments that are the subject of an underwriting or other distribution by UBS or its affiliates and may also enter into transactions with other clients of UBS Asset Management or its affiliates where such other clients have interests adverse to those of the funds. At times, these activities may cause UBS Asset Management or its affiliates to give advice to clients that may cause these clients to take actions adverse to the interests of the funds. To the extent affiliated transactions are permitted, the funds will deal with UBS Asset Management, UBS and its affiliates on an arms-length basis. UBS Asset Management or UBS may also have an ownership interest in certain trading or information systems used by the funds. The fund's use of such trading or information systems may enhance the profitability of UBS Asset Management and its affiliates.

It is also possible that, from time to time, UBS Asset Management or any of its affiliates may, although they are not required to, purchase and hold shares of the funds for UBS proprietary accounts and for Client Accounts. Increasing a fund's assets may enhance investment flexibility and diversification and may contribute to economies of scale that tend to reduce the expense ratio of certain types of funds. UBS Asset Management and its affiliates reserve the right to redeem at any time some or all of the shares of the funds acquired for UBS proprietary accounts and for Client Accounts. A large redemption of shares of a fund by UBS Asset Management or its affiliates or Client Accounts could significantly reduce the asset size of the fund, which might have an adverse effect on the fund's investment flexibility, portfolio diversification, expense ratio and may result in significant transaction costs. UBS Asset Management will consider the effect of redemptions on the fund and other shareholders in deciding whether and when to redeem its shares. UBS Asset Management's ability to allocate investments for UBS proprietary accounts and Client Accounts among the funds and unaffiliated investment companies and other investments may create conflicts of interest. For example, a fund's portfolio managers may manage certain Client Accounts. Because they have access to the holdings of the funds and knowledge of the investment strategies and techniques of the funds they could be subject to conflicts of interest in timing and amount of allocations of Client Account investments to or redemptions from a fund. Further, a situation could occur where an action for a fund could be adverse to the interest of such a Client Account or vice versa.

It is possible that the funds may invest in securities of companies with which UBS has or is trying to develop investment banking relationships as well as securities of entities in which UBS Asset Management or UBS has significant debt or equity investments or in which UBS makes a market. The funds also may invest in securities of companies to which UBS Asset Management or UBS provides or may someday provide research coverage. Such investments could cause conflicts between the interests of the funds and the interests of other UBS Asset Management or UBS clients. In making investment decisions for the funds, UBS Asset Management is not permitted to obtain or use material non-public information acquired by any division, department or affiliate of UBS Asset Management in the course of these activities. In addition, from time to time, UBS' activities may limit the funds'

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flexibility in purchases and sales of securities. When UBS is engaged in an underwriting or other distribution of securities of an entity, UBS Asset Management may be prohibited from purchasing or recommending the purchase of certain securities of that entity for the funds.

Present and future activities of UBS Asset Management and its affiliates, in addition to those described in this section, may give rise to additional conflicts of interest.

UBS AM may buy for a fund securities or obligations of issuers in which UBS or other funds or accounts have made, or are making, an investment in securities or obligations that are subordinate or senior to securities of the fund. For example, a fund may invest in debt securities of an issuer at the same time that UBS or other funds or accounts are investing, or currently have an investment, in equity securities of the same issuer. To the extent that the issuer experiences financial or operational challenges which may impact the price of its securities and its ability to meet its obligations, decisions by UBS (including UBS AM) relating to what actions to be taken may also raise conflicts of interests, and UBS may take actions for certain accounts that have negative impacts on other advisory accounts.

While UBS AM will make proxy voting decisions as it believes appropriate and in accordance with UBS AM's policies designed to help avoid conflicts of interest, proxy voting decisions made by UBS AM with respect to a fund's portfolio securities may have the effect of favoring the interests of other clients or businesses of other divisions or units of UBS. UBS AM's proxy voting policy is discussed in more detail in the section entitled "Proxy voting policies and procedures."

As a registered investment adviser under the Advisers Act, UBS AM is required to file a Form ADV with the SEC. Form ADV Part 2 contains information about assets under management, types of fee arrangements, types of investments, potential conflicts of interest, and other relevant information regarding UBS AM. A copy of UBS AM's Form ADV Parts 1 and 2 is available on the SEC's website (www.adviserinfo.sec.gov).

Other information

**Delaware statutory trust.** Although Delaware law statutorily limits the potential liabilities of a Delaware statutory trust's shareholders to the same extent as it limits the potential liabilities of a Delaware corporation's shareholders, shareholders of a fund could, under certain conflicts of laws jurisprudence in various states, be held personally liable for the obligations of the Trust or the funds. However, the Trust's Trust Instrument disclaims shareholder liability for acts or obligations of the Trust or its funds. The Trust Instrument provides for indemnification from each fund's property for all losses and expenses of any fund shareholder held personally liable for the obligations of a fund. Thus, the risk of a shareholder's incurring financial loss on account of shareholder liability is limited to circumstances in which a fund itself would be unable to meet its obligations, a possibility which UBS AM believes is remote and not material. Upon payment of any liability incurred by a shareholder solely by reason of being or having been a shareholder of a fund, the shareholder paying such liability will be entitled to reimbursement from the general assets of the fund. The trustees intend to conduct the operations of the funds in such a way as to avoid, as far as possible, ultimate liability of the shareholders for liabilities of the funds.

**Classes of shares.** UBS Select 100% US Treasury Preferred Fund offers Class T shares and Class P shares and UBS Select 100% US Treasury Institutional Fund offers Institutional shares and Token-Enabled shares. A share of each class of the fund represents an identical interest in the fund's investment portfolio and has the same rights, privileges and preferences. However, each class may differ with respect to expenses, including service fees, if any, other expenses allocable exclusively to each class, voting rights on matters exclusively affecting that class, and its exchange privilege, if any. Also, different share classes may have different investor eligibility requirements and different minimum initial investment requirements. The different expenses applicable to the different classes of shares of the fund will affect the performance of those classes. Each share of the fund is entitled to participate

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equally in dividends, other distributions and the proceeds of any liquidation of that fund. To the extent that there may be any differing expenses of the classes, dividends and liquidation proceeds on Class T shares, Class P shares, Institutional shares, and Token-Enabled shares will differ.

**Voting rights.** Shareholders of each fund are entitled to one vote for each full share held and fractional votes for fractional shares held. Voting rights are not cumulative and, as a result, the holders of more than 50% of all the shares of the Trust may elect all its board members. The shares of each series of the Trust will be voted separately, except when an aggregate vote of all the shares is required by law.

UBS Series Funds does not hold annual meetings. There normally will be no meetings of shareholders to elect trustees unless fewer than a majority of the trustees holding office have been elected by shareholders. Shareholders of record holding no less than two-thirds of the outstanding shares of UBS Series Funds may remove a board member by vote cast in person or by proxy at a meeting called for that purpose. A meeting will be called to vote on the removal of a board member at the written request of holders of record of at least 10% of the outstanding shares of UBS Series Funds.

**Prior names.** Prior to March 9, 2018, UBS Series Funds was known as UBS Money Series. Prior to August 28, 2007, UBS Select Treasury Institutional Fund was known as "UBS Select Treasury Fund." Prior to April 8, 2002, UBS Series Funds was known as Brinson Money Series, and UBS Select Money Market Fund was known as "Brinson Select Money Market Fund." Prior to May 9, 2001, UBS Series Funds was known as "Mitchell Hutchins LIR Money Series," and UBS Select Money Market Fund was known as "Mitchell Hutchins LIR Select Money Fund." Prior to July 28, 1999, UBS Series Funds was known as "Mitchell Hutchins Institutional Series." Prior to August 28, 2007, the shares issued by UBS Select Treasury Institutional Fund had the designation "Institutional shares."

**Custodian; transfer and dividend agent.** State Street, located at One Congress Street, Suite 1, Boston, MA 02114, is custodian of the master funds' assets and provides other services to the funds. BNY Mellon Investment Servicing (US) Inc. ("BNY Mellon"), a subsidiary of BNY Mellon Bank, N.A., serves as each fund's transfer and dividend disbursing agent. BNY Mellon is located at 400 Bellevue Parkway, Wilmington, DE 19809.

**Counsel.** The law firm of Dechert LLP, Three Bryant Park, 1095 Avenue of the Americas, New York, NY 10036, serves as counsel to the funds. Dechert LLP also has acted as counsel to UBS AM in connection with other matters. Stradley Ronon Stevens & Young, LLP, 100 Park Avenue, Suite 2000, New York, NY 10017, serves as independent counsel to the Independent Trustees.

**Independent registered public accounting firm.** Ernst & Young LLP, One Manhattan West, New York, NY 10001, serves as independent registered public accounting firm for the funds.

Financial statements

The funds' [financial statements](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/0001060517/000119312525156261/d920425dncsr.htm) for the fiscal year ended April 30, 2025 and the report thereon of the funds' independent registered public accounting firm, which are contained in the funds' [Form N-CSR](http://www.sec.gov/Archives/edgar/data/1060517/000119312525156261/d920425dncsr.htm) dated April 30, 2025, are incorporated by this reference in this SAI. The funds' semi-annual financial statements as of and for the fiscal period ended October 31, 2025 are unaudited and are incorporated herein by reference to the funds' most recent [Form N-CSR](http://www.sec.gov/Archives/edgar/data/../../../ix?doc=/Archives/edgar/data/1060517/000119312526008851/d31005dncsrs.htm) for their fiscal period ended October 31, 2025.

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**You should rely only on the information contained or referred to in the prospectus for a particular fund and this Statement of Additional Information. The funds and their principal underwriter have not authorized anyone to provide you with information that is different. The prospectuses and this Statement of Additional Information are not an offer to sell shares of the funds in any jurisdiction where the funds or their principal underwriter may not lawfully sell those shares.**© UBS 2026. All rights reserved.

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