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Class P2 Prospectus | UBS Sustainable Development Bank Bond Fund

UBS Sustainable Development Bank Bond Fund

Investment objective

The Fund seeks current income.

Fees and expenses

These tables describe the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. Shares of Class P2 are available for purchase on behalf of clients of a fee-based program or certain other advisory programs in which UBS Asset Management (Americas) Inc., the Fund's investment advisor and administrator ("UBS AM (Americas)" or the "Advisor"), exercises investment discretion. Clients pay a wrap fee or a similar advisory fee to participate in such programs. Shares of Class P2 are also available for purchase on behalf of institutional clients with which the Advisor or its affiliates has signed a separate investment management agreement, pursuant to which such clients pay an advisory fee.

Shareholder fees (fees paid directly from your investment)

Shareholder Fees	Class P2 Prospectus UBS Sustainable Development Bank Bond Fund Class P2
Maximum front-end sales charge (load) imposed on purchases (as a % of offering price)	none
Maximum contingent deferred sales charge (load) (CDSC) (as a % of purchase or sales price, whichever is less)	none

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

Annual Fund Operating Expenses	Class P2 Prospectus UBS Sustainable Development Bank Bond Fund Class P2
Management fees	0.15%
Distribution and/or service (12b-1) fees	none
Other expenses	0.53%	[1]
Total annual fund operating expenses	0.68%
Less management fee waiver/expense reimbursements	0.53%	[2]
Total annual fund operating expenses after management fee waiver/expense reimbursement	0.15%	[2]

Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the Fund for the time periods indicated and then sell all of your shares at the end of those periods unless otherwise stated. The example also assumes that your investment has a 5% return each year and that the Fund's operating expenses remain the same. The costs described in the example reflect the expenses of the Fund that would result from the contractual fee waiver and expense reimbursement agreement with the Advisor for the first year only. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:

Expense Example	1 year	3 years	5 years	10 years
Class P2 Prospectus | UBS Sustainable Development Bank Bond Fund | Class P2 | USD ($)	15	164	326	796

Portfolio turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate

higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund's performance. During the most recent fiscal year, the Fund's portfolio turnover rate was 16% of the average value of its portfolio.

Principal strategies

Principal investments

Under normal circumstances, the Fund invests at least 80% of its net assets (plus borrowings for investment purposes, if any) in bonds and/or instruments that provide exposure to bonds issued by development banks. Development banks are financial organizations formed by government entities to promote economic and social development. The Fund invests in multilateral development bank bonds but may also invest in regional or national development bank obligations. The Fund's investment in obligations issued by the International Bank for Reconstruction and Development and the Inter-American Development Bank may be significant, but the Fund normally will not invest more than 25% of its net assets in either issuer.

Under normal circumstances, the Fund will invest in securities that, at the time of purchase, possess a minimum rating of A3 by Moody's Investors Service, Inc. ("Moody's") or A- by Standard & Poor's Financial Services LLC ("S&P") or Fitch Ratings, Inc. ("Fitch"), comparably rated by another nationally recognized statistical rating organization, or, if unrated, are determined by the Advisor to be of comparable quality.

The Fund's investments in fixed income securities may have all types of interest rate payment and reset terms. The Fund generally invests only in US dollar-denominated securities.

The Fund may, but is not required to, engage in derivatives transactions. Derivatives instruments such as futures may be used for risk management purposes to hedge against a specific security or for investment (non-hedging) purposes to earn income or adjust portfolio duration. The Fund does not seek to use derivatives extensively.

The Fund may invest in exchange-traded funds ("ETFs") to gain exposure to certain asset classes.

The Fund is a non-diversified fund, which means that the Fund may invest more of its assets in a smaller number of issuers than a diversified investment company.

Management process

The Advisor seeks to invest in bonds issued by development banks. The Advisor constructs the portfolio consisting of multilateral and regional development banks.

The Advisor focuses primarily on bonds issued by multilateral development banks which may include, but are not limited to, the International Bank for Reconstruction and Development and other member institutions of the World Bank Group, the Inter-American Development Bank, the Asian Development Bank, the African Development Bank, and the European Bank for Reconstruction and Development. Development banks are formed by their member states with the objective to provide financial and technical assistance to improve overall living standards through sustainable economic development and growth. While each development bank has a distinct focus, development banks generally use their capital for projects that seek to improve the state of the developing world, promote sustainable growth and raise living standards.

The Advisor selects investments for the Fund based on available supply and liquidity parameters (including, for example, such factors as evaluating amounts outstanding, available dealer inventory, and volumes traded in the secondary market) utilizing a stratified sampling approach (investing in a representative cross-section of the investment universe) to optimize tracking error and minimize transaction cost. The Fund will be managed relative to a composite index, which is a blend of two market indexes designed to measure the performance of the US dollar denominated multilateral development bank bond market. The Fund does not seek to directly replicate the index. The Fund's composite index is the Solactive Global Multilateral Development Bank Bond USD 40% 1-5 Year 60% 5-10 Year Total Return Index. (The Fund reserves the right in its discretion to change the index.) The Fund's development bank bond investments may include issuers that are not part of the composite index. The Fund will seek to maintain a concentrated portfolio of development bank bonds emphasizing multilateral development banks. The portfolio management team will select the bonds in the market that meet their selection criteria with intention to provide similar risk/return characteristics as the broader development bank bond market.

The Fund may engage in active trading to adjust the portfolio in response to investor activity and to rebalance the portfolio as new development bank issuers come to the market and existing issuers enter the index or mature.

Main risks

All investments carry a certain amount of risk, and the Fund cannot guarantee that it will achieve its investment objective. You may lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Below are some of the specific risks of investing in the Fund.

Risks of development bank bonds: The value of the Fund's investments in bonds issued by development banks may fall due to adverse financial market developments in the United States and abroad. Borrowers from development banks include foreign countries, which may include emerging market countries, and borrowers of specific development banks also include the private sector with or without government guarantee. Therefore, negative economic, social and political developments could affect the ability of a borrower to repay its loan to the development bank and thus affect its financial condition. In addition, investments in such development bank bonds may involve special risks because the Fund may have limited legal recourse in the event of default. Also, development bank bonds may sometimes be less liquid and more difficult to sell and to value than high-quality securities of US issuers. Bonds issued by a development bank are backed by the shareholders of the development bank. The development bank may be supported via various mechanisms including, preferred creditor status, equity injections by its shareholders and callable capital, even though the latter may have never been tested with respect to an issuer. Changes in the shareholder structure of a development bank or changes in the strength of the support by its shareholders could affect the credit rating and thus the value of the bonds issued by the development bank.

Interest rate risk: An increase in prevailing interest rates typically causes the value of fixed income securities to fall. Changes in interest rates will likely affect the value of longer-duration fixed income securities more than shorter-duration securities and higher quality securities more than lower quality securities. When interest rates are falling, some fixed income securities provide that the issuer may repay them earlier than the maturity date, and if this occurs the Fund may have to reinvest these repayments at lower 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. During periods when interest rates are low or there are negative interest rates, the Fund's performance may be negatively impacted, and the Fund may experience increased volatility of its net asset value per share.

Concentration risk: The Fund concentrates in the bonds of development banks. The risk is that if the Fund has most of its investments in a single industry, its portfolio will be more susceptible to factors adversely affecting that industry than would a more diverse portfolio of securities.

Credit risk: The risk that the Fund could lose money if the issuer or guarantor of a fixed income security, or the counterparty to or guarantor of a derivative contract, is unable or unwilling to meet its financial obligations. This

risk is likely greater for lower quality investments than for investments that are higher quality.

Liquidity risk: The risk that investments cannot be readily sold at the desired time or price, and the Fund may have to accept a lower price or may not be able to sell the security at all. An inability to sell securities can adversely affect the Fund's value or prevent the Fund from taking advantage of other investment opportunities. Liquid portfolio investments may become illiquid or less liquid after purchase by the Fund due to low trading volume, adverse investor perceptions and/or other market developments. In recent years, the number and capacity of dealers that make markets in fixed income securities has decreased. Consequently, the decline in dealers engaging in market making trading activities may increase liquidity risk, which can be more pronounced in periods of market turmoil. Liquidity risk may be magnified in a rising interest rate environment or when investor redemptions from fixed income funds may be higher than normal, causing increased supply in the market due to selling activity. Liquidity risk includes the risk that the Fund will experience significant net redemptions at a time when it cannot find willing buyers for its portfolio securities or can only sell its portfolio securities at a material loss.

Non-diversification risk: The Fund is a non-diversified investment company, which means that the Fund may invest more of its assets in a smaller number of issuers than a diversified investment company. As a non-diversified fund, the Fund's share price may be more volatile, and the Fund has a greater potential to realize losses upon the occurrence of adverse events affecting a particular issuer.

Portfolio turnover risk: High portfolio turnover from frequent trading will increase the Fund's transaction costs and may increase the portion of the Fund's capital gains that are realized for tax purposes in any given year. The Fund does not restrict the frequency of trading in order to limit expenses or the tax effect that its distributions may have on shareholders.

Market risk: The market value of the Fund's investments may fluctuate, sometimes rapidly or unpredictably, as the stock and bond markets fluctuate. Market risk may affect a single issuer, industry, or sector of the economy, or it may affect the market as a whole.

Leverage risk associated with financial instruments: The use of financial instruments to increase potential returns, including derivatives used for investment (non-hedging) purposes, may cause the Fund to be more volatile than if it had not been leveraged. The use of leverage may also accelerate the velocity of losses and can result in losses to the Fund that exceed the amount originally invested.

Derivatives risk: The value of "derivatives"—so called because their value "derives" from the value of an underlying asset, reference rate or index—may rise or fall more rapidly than other investments. It is possible for the Fund to lose more than the amount it invested in the derivative. The risks of investing in derivative instruments also include market risk, management risk, counterparty risk (which is the risk that a counterparty to a derivative contract is unable or unwilling to meet its financial obligations) and the risk that changes in the value of a derivative may not correlate perfectly with the underlying asset, rate, index or overall market security. Derivatives relating to fixed income markets are especially susceptible to interest rate risk and credit risk. These derivatives risks are different from, and may be greater than, the risks associated with investing directly in securities and other instruments.

Investing in ETFs risk: The Fund's investment in ETFs may subject the Fund to additional risks than if the Fund would have invested directly in the ETF's underlying securities. These risks include the possibility that an ETF may experience a lack of liquidity that can result in greater volatility than its underlying securities; an ETF may trade at a premium or discount to its net asset value; an ETF may not replicate exactly the performance of the benchmark index it seeks to track; trading an ETF's shares may be halted if the listing exchange's officials deem such action appropriate; and a passively managed ETF would not necessarily sell a security because the issuer of the security was in financial trouble unless the security is removed from the index that the ETF seeks to track. In addition, investing in an ETF may also be more costly than if a Fund had owned the underlying securities directly. The Fund, and indirectly, shareholders of the Fund, bear a proportionate share of the ETF's expenses, which include management and advisory fees and other expenses. In addition, the Fund will pay brokerage commissions in connection with the purchase and sale of shares of the ETF.

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

Performance

The performance information that follows shows the Fund's Class P performance information in a bar chart and an average annual total returns table. There is no performance information quoted for the Class P2 shares of the Fund as the Class P2 shares have not completed a full calendar year of operations as of the date of this prospectus. Although the Class P2 shares are invested in the same portfolio of securities as the Class P shares, returns for the Class P2 shares will differ from the Class P shares to the extent that the Class P2 shares are subject to different expenses. The information provides some indication of the risks of investing in the Fund by showing the Fund's performance from year to year and

by showing how the Fund's average annual total returns compare with those of a broad measure of market performance. The Bloomberg U.S. Treasury Index shows how the Fund's performance compares to an index that is designed to measure US dollar-denominated, fixed-rate, nominal debt issued by the US Treasury. The Solactive Global Multilateral Development Bank Bond USD 40% 1-5 Year 60% 5-10 Year Total Return Index is a composite index, constructed from a blend of two market indexes designed to measure the performance of the US dollar-denominated multilateral development bank bond market. Indices reflect no deduction for fees, expenses or taxes. The Fund's past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. Updated performance for the Fund is available at www.ubs.com/us-mutualfundperformance.

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

Total return (Class P)*

* 2019 is the Fund's first full year of operations.

Total return January 1 - September 30, 2021: (1.78)%
Best quarter during calendar year shown—1Q 2020: 5.50%
Worst quarter during calendar year shown—4Q 2019: (0.44)%

Average annual total returns (for the periods ended December 31, 2020)

Average Annual Returns - Class P2 Prospectus - UBS Sustainable Development Bank Bond Fund	Average Annual Returns, 1 Year	Average Annual Returns, Life of class	Average Annual Returns, Inception Date
Class P	6.80%	7.23%	Oct. 24, 2018
After Taxes on Distributions | Class P	5.28%	5.89%
After Taxes on Distributions and Sale of Fund Shares | Class P	4.24%	5.03%
Bloomberg U.S. Treasury Index (reflects no deduction for fees, expenses or taxes)	8.00%	8.15%
Solactive Global Multilateral Development Bank Bond USD 40% 1-5 Year 60% 5-10 Year Total Return Index	6.89%	7.49%

[1] "Other expenses" include "Acquired fund fees and expenses," which were less than 0.01% of the average net assets of the Fund.

[2] The Trust, with respect to the Fund, and the Advisor, have entered into a written agreement pursuant to which the Advisor has agreed to waive its management