UBS Global Allocation Fund

Summary Prospectus | October 26, 2018

Before you invest, you may want to review the Fund's prospectus and statement of additional information ("SAI"), which contain more information about the Fund and its risks. You can find the Fund's prospectus, SAI and other information about the Fund online at http://www.ubs.com/us/en/asset_management/individual_investors/mutual_fund.html. You can also get this information at no cost by calling 1-800-647 1568 or by sending an email request to ubs@fundinsite.com. The current prospectus and SAI, dated October 26, 2018, are incorporated by reference into this summary prospectus (i.e., they are legally a part of this summary prospectus).

Share Class: Ticker Symbol

Class A				Class P
BNGLX					BPGLX

Investment objective

The Fund seeks to maximize total return, consisting of capital appreciation and current income.

Fees and expenses

These tables describe the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for a sales charge waiver or discount if you and your family invest, or agree to invest in the future, at least $50,000 in the Fund. More information about these and other discounts and waivers, as well as eligibility requirements for each share class, is available from your financial advisor and in "Managing your fund account" beginning on page 86 of the Fund's prospectus and in "Reduced sales charges, additional purchase, exchange and redemption information and other services" beginning on page 99 of the Fund's SAI. Different intermediaries and financial professionals may make available different sales charge waivers or discounts. These variations are described in Appendix A beginning on page A-1 of the prospectus.

Shareholder fees (fees paid directly from your investment)

	Class A			Class P
Maximum front-end sales charge (load) imposed on purchases (as a % of offering price)		5.50	%		None
Maximum contingent deferred sales charge (load) (CDSC) (as a % of purchase or sales price, whichever is less)		None¹			None

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

	Class A			Class P
Management fees		0.80	%		0.80	%
Distribution and/or service (12b-1) fees		0.25			None
Other expenses		0.35			0.34
Acquired fund fees and expenses		0.09			0.09
Total annual fund operating expenses²		1.49			1.23
Less management fee waiver/expense reimbursements³		0.20			0.19
Total annual fund operating expenses after management fee waiver/expense reimbursements^2,3		1.29			1.04

¹ Purchases of $1 million or more that were not subject to a front-end sales charge are subject to a 1% CDSC if sold within one year of the purchase date.

² Since the "Acquired fund fees and expenses" are not directly borne by the Fund, they are not reflected in the Fund's financial statements, and therefore the amounts listed in "Total annual fund operating expenses" will differ from those presented in the Financial highlights.

³ The Trust, with respect to the Fund, and UBS Asset Management (Americas) Inc., the Fund's investment advisor and administrator ("UBS AM (Americas)" or the "Advisor"), have entered into a written agreement pursuant to which the Advisor has agreed to waive a portion of its management fees and/or to reimburse expenses (excluding expenses incurred through investment in other investment companies, interest, taxes, brokerage commissions, and extraordinary expenses to the extent necessary so that the Fund's ordinary operating expenses (excluding expenses incurred through investment in other investment companies, interest, taxes, brokerage commissions, and extraordinary expenses), through the period ending October 29, 2019, do not exceed 1.20% for Class A shares and 0.95% for Class P shares. Pursuant to the written agreement, the Advisor is entitled to be reimbursed for any fees it waives and expenses it reimburses to the extent such reimbursement can be made during the three fiscal years following the date on which such fee waivers and expense reimbursements were made, provided that the reimbursement of the Advisor by the Fund will not cause the Fund 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 the recoupment. The fee waiver/expense reimbursement agreement may be terminated by the Fund's Board of Trustees at any time and also will terminate automatically upon the expiration or termination of the Fund's advisory contract with the Advisor. Upon termination of the fee waiver/expense reimbursement agreement, however, UBS AM (Americas)'s three year recoupment rights will survive.

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

	1 year		3 years		5 years		10 years
Class A	$	674	$	977	$	1,301	$	2,215
Class P		106		372		657		1,472

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 54% of the average value of its portfolio.

Principal strategies

Principal investments

In order to achieve the Fund's objective, the Fund employs an asset allocation strategy that seeks to maximize total return. The Fund's investment advisor ("UBS AM (Americas)" or the "Advisor") does not represent or guarantee that the Fund will meet this total return goal.

Under normal circumstances, the Fund will invest in securities and derivatives to gain exposure to equity, fixed income, and alternative asset class securities, including, but not limited to, convertible bonds and real estate securities, including real estate investment trusts ("REITs") and real estate operating companies. The Fund may gain exposure to issuers located within and outside the United States, including securities of issuers in both developed (including the United States) and emerging markets countries.

Investments in fixed income securities may include, but are not limited to, debt securities of governments throughout the world (including the United States), their agencies and instrumentalities, debt securities of corporations, mortgage-backed securities and asset-backed securities. The Fund may invest in securities of any maturity greater than one year and such securities may be either investment grade or high yield (lower-rated or

"junk bonds") securities. Investments in equity securities may include, but are not limited to, common stock and preferred stock. The Fund may invest in other open-end investment companies advised by the Advisor and third-party passively managed exchanged-traded funds ("ETFs") to gain exposure to certain asset classes. The Fund may also take active positions on volatility to generate returns or to hedge the Fund's portfolio.

The Fund may, but is not required to, use exchange-traded or over-the-counter derivative instruments for risk management purposes or as part of the Fund's investment strategies. Generally, derivatives are financial contracts whose value depends upon, or is derived from, the value of an underlying asset, reference rate, index or other market factor and may relate to stocks, bonds, interest rates, credit, currencies or currency exchange rates, commodities and related indexes. The derivatives in which the Fund may invest include index options, futures, forward agreements, swap agreements (including, interest rate, credit default and inflation swaps), equity participation notes and equity linked notes. All of these derivatives may be used for risk management purposes, such as hedging against a specific security or currency (except with respect to equity participation notes and equity linked notes), or to manage or adjust the risk profile of the Fund. In addition, all of the derivative instruments listed above may be used for investment (non-hedging) purposes to earn income; to enhance returns; to replace more traditional direct investments; to obtain exposure to certain markets; or to establish net short positions for individual markets, currencies or securities. Futures on indices, forward agreements, interest rate swaps and credit default swaps may also be used to adjust the Fund's portfolio duration.

Management process

The Advisor will manage the Fund's portfolio using the following investment process as described below:

The strategy invests in the full spectrum of instruments and markets globally. The Advisor believes that the Advisor is able to improve the return outcome and risk management of the Fund by employing a well diversified strategy across a broad global opportunity set. Returns are generated from asset allocation across markets, currency and security selection.

Asset allocation decisions are primarily driven by UBS AM (Americas)'s assessment of valuation and prevailing market conditions in the United States and around the world. Using a systematic approach, the portfolio management team analyzes the asset classes and investments across equities, fixed income, and alternative asset classes (including currency), considering both fundamental valuation, economic and other market indicators. Regarding valuation, the Advisor evaluates whether asset classes and investments are attractively priced relative to fundamentals. The starting point is to assess the

intrinsic value of an asset class, as determined by the fundamentals that drive an asset class' future cash flow. The intrinsic value represents a long term anchor point to which the Advisor believes the asset class will eventually revert.

Fair value estimates of asset classes and markets are an output of UBS AM (Americas)'s proprietary valuation models. Discounting the asset's future cash flow using a discount rate that appropriately reflects the inherent investment risk associated with holding the asset gives the asset's fair value. The competitive advantage of the Advisor's models lies in the quality and consistency of the inputs used and, therefore, the reliability of valuation conclusions. The discrepancy between actual market level and fair value (the price/value discrepancy) is the primary valuation signal used in identifying investment opportunities.

Next, the Advisor assesses additional market indicators and considers the effect that other determinants of economic growth and overall market volatility will have on each asset class. While in theory price/value discrepancies may resolve themselves quickly and linearly, in practice price/value discrepancy can grow larger before it resolves. While valuation models have proven effective at identifying longer-term price/value discrepancies, in the shorter term other factors can swamp valuation considerations. Thus, the Advisor incorporates an additional discipline in our idea generation process. The Advisor refers to this additional step in its idea generation process as market behavior analysis. Adding this step helps the Advisor to understand what other market indicators might drive the market towards or away from fundamental value. The Advisor performs systematic analysis of non-valuation drivers using models measuring sentiment, momentum and flows, market stress, the stage of the economic cycle, as well as an assessment of the general macroeconomic landscape. Conversely, valuation considerations tend to dominate when an asset class is substantially above or below fair value, but the Advisor recognizes that the use of market behavior analysis during these periods is very important to helping improve the timing in and out of these asset classes with very stretched valuations.

The asset allocation process is structured around the Investment Solutions Investment Committee (the "ISIC Committee") meetings, which provides a forum for debate and the exploration of all ramifications of any investment decision, rather than aiming for a consensus to be reached. Instead, any voting member of the ISIC Committee can sponsor a trade idea, preparing a detailed investment thesis to support the view. An investment thesis has to define the investment rationale based on valuation and market behavioral influences, the time scale for it being realized, the transaction costs and the potential milestones the Advisor would expect to evaluate whether or not the view is correct. The

sponsor is then responsible for convincing another member of the ISIC Committee to support the idea as co-sponsor.

Bottom up selection across active equity and fixed income markets can be utilized as part of the asset allocation process at the asset class level. With respect to specific equity securities for inclusion in the Fund's equity asset classes, the Advisor may utilize fundamental valuation, quantitative and growth-oriented strategies. The Advisor's bottom up fixed income security selection strategy combines judgments about the absolute value of the fixed income universe and the relative value of issuer sectors, maturity intervals, security durations, credit qualities and coupon segments, as well as specific circumstances facing the issuers of fixed income securities.

The Advisor uses both fundamental valuation and market behavior analysis to make the two-pronged determination of risk budget and risk allocation. The Advisor works closely with the Risk Management team, members of which attend the ISIC Committee meetings, to determine the appropriate amount of risk capital to allocate to the underlying trade ideas given the strategy's risk budget and objectives, prevailing investment opportunities, and other strategy exposures. To assist in this process the Risk Management team performs scenario and correlation analysis to better understand the risk and diversification of the overall strategy, and attempts to ensure that unintended factor exposures are identified, managed and monitored.

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.

Asset allocation risk: The risk that the Fund may allocate assets to an asset category that performs poorly relative to other asset categories.

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.

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 securities. Derivatives relating to fixed income markets are especially susceptible to interest rate risk and credit risk. In addition, many types of swaps and other non-exchange traded derivatives may be subject to liquidity risk, credit risk and mispricing or valuation complexity. These derivatives risks are different from, and may be greater than, the risks associated with investing directly in securities and other instruments.

Emerging market risk: There are additional risks inherent in investing in less developed countries that are applicable to the Fund. Compared to the United States and other developed countries, investments in emerging market issuers may decline in value because of unfavorable foreign government actions, greater risks of political instability or the absence of accurate information about emerging market issuers. Further, emerging countries may have economies based on only a few industries and securities markets that trade only a small number of securities and employ settlement procedures different from those used in the United States. Prices on these exchanges tend to be volatile and, in the past, securities in these countries have offered greater potential for gain (as well as loss) than securities of companies located in developed countries. Further, investments by foreign investors are subject to a variety of restrictions in many emerging countries. Countries such as those in which the Fund may invest may experience high rates of inflation, high interest rates, exchange rate fluctuations or currency depreciation, large amounts of external debt, balance of payments and trade difficulties and extreme poverty and unemployment.

Foreign investing risk: The value of the Fund's investments in foreign securities may fall due to adverse political, social and economic developments abroad and due to decreases in foreign currency values relative to the US dollar. Investments in foreign government bonds involve special risks because the Fund may have limited legal recourse in the event of default. Also, foreign securities are sometimes less liquid and more difficult to sell and to value than securities of US issuers. These risks are greater for investments in emerging market issuers.

High yield bond risk: The risk that the issuer of bonds with ratings of Ba1 or lower by Moody's Investors Service, Inc. ("Moody's") or BB+ or lower 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 to be of comparable quality by the Advisor, will default or otherwise be unable to honor a

financial obligation (also known as lower-rated or "junk bonds"). These securities are considered to be predominately speculative with respect to an issuer's capacity to pay interest and repay principal in accordance with the terms of the obligations. Lower-quality bonds are more likely to be subject to an issuer's default or downgrade than investment grade (higher quality) bonds.

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 risks associated with rising interest rates may be more pronounced in the near future as interest rates rise from historically low rates.

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; or an ETF may not replicate exactly the performance of the benchmark index it 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.

Investing in other funds risk: The Fund's investment performance is affected by the investment performance of the underlying funds in which the Fund may invest, including ETFs. Through its investment in the underlying funds, the Fund is subject to the risks of the underlying funds' investments and subject to the underlying funds' expenses.

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.

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.

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

Market risk: The risk that 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.

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

Passive investment risk: ETFs purchased by the Fund are not actively managed and may be affected by general decline in market segments relating to their respective indices. An ETF typically invests in securities included in, or representative of, its index regardless of their investment merits and does not attempt to take defensive positions in declining markets.

Real estate securities and REITs risk: The risk that the Fund's performance will be affected by adverse developments in the real estate industry. Real estate values may be affected by a variety of factors, including: local, national or global economic conditions; changes in zoning or other property-related laws; environmental regulations; interest rates; tax and insurance considerations; overbuilding; property taxes and operating expenses; or declining values in a neighborhood. Similarly, a REIT's performance depends on the types, values, locations and management of the properties it owns. In addition, a REIT may be more susceptible to adverse developments affecting a single project or market segment than a more diversified investment. Loss of status as a qualified REIT under the US federal tax laws could adversely affect the value of a particular REIT or the market for REITs as a whole.

Small- and mid-capitalization risk: The risk that securities of smaller capitalization companies tend to be more volatile and less liquid than securities of larger capitalization companies. This can have a disproportionate effect on the market price of smaller capitalization companies and affect the Fund's ability to purchase or sell these securities. In general, smaller capitalization companies are more vulnerable than larger companies to adverse business or economic developments, and they may have more limited resources.

Tracking error risk for ETFs and derivatives: Imperfect correlation between a derivative or ETF's portfolio securities and those in its index, rounding of prices, the timing of cash flows, the ETF's size, changes to the index and regulatory requirements may cause tracking error, which is the divergence of an ETF's performance from that of its underlying index. This risk may be heightened during times of increased market volatility or other unusual market conditions. Tracking error also may result because an ETF incurs fees and expenses while its underlying index does not.

US Government securities risk: There are different types of US government securities with different levels of credit risk, including risk of default, depending on the nature of the particular government support for that security. For example, a US government-sponsored entity, although chartered or sponsored by an Act of Congress, may issue securities that are neither insured nor guaranteed by the US Treasury and are therefore riskier than those that are.

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. The information provides some indication of the risks of investing in the Fund by showing changes in 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 MSCI All Country World Index (net) shows how the Fund's performance compares to an index that is designed to measure the equity market performance of developed and emerging markets. The FTSE World Government Bond Index (Hedged in USD) shows how the Fund's performance compares to an index composed of straight (i.e., not floating rate or index-linked) government bonds with a one-year minimum maturity that is hedged back to the US dollar. The Fund's secondary benchmark index is a blend of 60% MSCI All Country World Index (net)/40% FTSE World Government Bond Index (Hedged in USD) and shows how the Fund's performance compares with a blend of prominent industry indices that better reflect the asset allocation of the Fund's portfolio. Indices reflect no deduction for fees, expenses or taxes, except for the MSCI All Country World Index (net) which reflects no deduction for fees and expenses. 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 after-tax 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)

Total return January 1 - September 30, 2018: 1.13%
Best quarter during calendar years shown—2Q 2009: 23.56%
Worst quarter during calendar years shown—4Q 2008: (21.44)%

Average annual total returns
(figures reflect sales charges) (for the periods ended December 31, 2017)

Class (inception date)	1 year			5 years			10 years
Class A (6/30/97) Return before taxes		10.19	%		5.12	%		2.55	%
Class P (8/31/92) Return before taxes		17.09			6.61			3.44
Return after taxes on distributions		16.51			6.02			2.17
Return after taxes on distributions and sale of fund shares		9.91			4.97			2.20
MSCI All Country World Index (net)		23.97			10.80			4.65
FTSE World Government Bond Index (Hedged in USD)		2.14			3.11			3.89
60% MSCI All Country World Index (net)/40% FTSE World Government Bond Index (Hedged in USD)		14.79			7.80			4.75

Investment advisor

UBS Asset Management (Americas) Inc. serves as the investment advisor to the Fund.

Portfolio managers

• Philip Brides, portfolio manager of the Fund since 2014.

• Gian Plebani, portfolio manager of the Fund since 2017.

Purchase & sale of Fund shares

You may purchase, redeem or exchange shares of the Fund on any business day, which is any day the New York Stock Exchange is open for business. You may purchase, redeem or exchange Class A or P shares of the Fund either through a financial advisor or directly from the Fund. In general, the minimum initial investment for Class A shares is $1,000, and the minimum subsequent investment is $100; and the minimum investment for Class P shares is $5 million ($1,000 for investors who are clients of wrap fee advisory programs (with a minimum subsequent investment of $100)).

Tax information

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

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), the Fund and its related companies may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the 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 Web site for more information.