UBS Money SeriesProspectus Supplement

Supplement to the Prospectus dated August 28, 2017

Includes:‰ UBS RMA Government Money Market Fund

January 2, 2018

Dear Investor:

The purpose of this supplement is to update certain information contained in the Prospectus for UBS RMA Govern-ment Money Market Fund (the “fund”) regarding certain program account fees associated with investments in thefund.

Effective in 2018, UBS Financial Services Inc. is changing certain program account fees. As a result, theshareholder fee table included on page 3 of the “Fund summary” section in the Prospectus is revised asfollows:

Shareholder fees (fees paid directly from your investment)

Maximum front-end sales charge (load) imposed on purchases None

Maximum deferred sales charge (load) None

Maximum account fee

UBS Financial Services Inc. RMA Program $175

UBS Financial Services Inc. Business Services Account BSA Program $175

UBS Financial Services Inc. Basic Investment Account Program $100

UBS Financial Services Inc. may charge other account fees for certain other features offered through its programs.Please contact your Financial Advisor for more information, including the timing of the assessment of any applicablefee to your account.

PLEASE BE SURE TO RETAIN THIS IMPORTANT INFORMATION FOR YOUR FUTURE REFERENCE.

ZS-931

UBS RMA GovernmentMoney Market FundProspectus | August 28, 2017

Ticker symbol: (RMGXX)

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

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

Contents

The fundWhat every investor should know about the fund

Fund summaryUBS RMA Government Money Market Fund 3

More information about the fund 7

Your investmentInformation for managing your fund accountManaging your fund account 11—Buying shares—Selling shares—Additional information about your account—Market timing—Pricing and valuation

Additional informationAdditional important information about the fundManagement 16Dividends and taxes 17Disclosure of portfolio holdings and other information 19Financial highlights 20Where to learn more about the fund Back cover

Please find the UBS family of funds privacy notice on page 21. Please find the UBS Asset Man-agement business continuity planning overview on page 22.

The fund is not a complete or balanced investment program.

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UBS RMA Government Money Market FundFund summary

Investment objectiveMaximum current income consistent with liquidity and the preservation of capital.

Fees and expenses of the fundThese tables describe the fees and expenses that you may pay if you buy and hold shares of the fund.

Shareholder fees (fees paid directly from your investment)

Maximum front-end sales charge (load) imposed on purchases None

Maximum deferred sales charge (load) None

Maximum account fee

UBS Financial Services Inc. RMA Program $ 150

UBS Financial Services Inc. Business Services Account BSA Program $ 150

UBS Financial Services Inc. Basic Investment Account Program $ 75

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

Management fees 0.20%

Other expenses 0.28

Shareholder servicing fee 0.25

Miscellaneous expenses 0.03

Total annual fund operating expenses 0.48

* The fund invests in securities through an underlying master fund, Government Master Fund. This table reflects the direct expenses of the fund and itsshare of expenses of Government Master Fund, including management fees allocated from Government Master Fund. Management fees are comprisedof investment advisory and administration fees.

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ExampleThis example is intended to help you compare the cost of investing in the fund with the cost of investing inother mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indi-cated and then redeem all of your shares at the end of those periods. The example also assumes that yourinvestment 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:

1 year 3 years 5 years 10 years

UBS RMA Government Money Market Fund $49 $154 $269 $604

This example does not reflect the above referenced program fees.

Principal strategiesPrincipal investmentsThe fund is a money market fund and seeks to maintain a stable price of $1.00 per share. To do this, thefund invests in a diversified portfolio of high quality, US government money market instruments and inrelated repurchase agreements.

Money market instruments generally are short-term debt obligations and similar securities. They also mayinclude longer-term bonds that have variable interest rates or other special features that give them thefinancial characteristics of short-term debt. The fund has adopted a policy to invest 99.5% or more of itstotal assets in cash, government securities, and/or repurchase agreements that are collateralized fully (i.e.,collateralized by cash and/or government securities) in order to qualify as a “government money marketfund” under federal regulations. By operating as a government money market fund, the fund is exemptfrom requirements that permit the imposition of a liquidity fee and/or temporary redemption gates. Whilethe fund’s board may elect to subject the fund to liquidity fee and gate requirements in the future, theboard has not elected to do so at this time. Many US government money market instruments pay incomethat is generally exempt from state and local income tax, although they may be subject to corporate fran-chise tax in some states. In addition, under normal circumstances, the fund invests at least 80% of its netassets in US government securities, including government securities subject to repurchase agreements.

The fund may invest a significant percentage of its assets in repurchase agreements. Repurchase agree-ments are transactions in which the fund purchases government securities and simultaneously commits toresell them to the same counterparty at a future time and at a price reflecting a market rate of interest.Income from repurchase agreements may not be exempt from state and local income taxation. Repur-chase agreements often offer a higher yield than investments directly in government securities. In decidingwhether an investment in a repurchase agreement is more attractive than a direct investment in govern-ment securities, the fund considers the possible loss of this tax advantage.

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

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Management processUBS Asset Management (Americas) Inc. (“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 fundbased 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 buysecurities that pay the highest yield.

Principal risksAll investments carry a certain amount of risk, and the fund cannot guarantee that it will achieve its invest-ment objective.

You could lose money by investing in the fund. Although the fund seeks to preserve the value of yourinvestment at $1.00 per share, it cannot guarantee it will do so. An investment in the fund is not insuredor guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The fund’ssponsor has no legal obligation to provide financial support to the fund, and you should not expect thatthe sponsor will provide financial support to the fund at any time.

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

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

US Government securities risk: There are different types of US government securities with different lev-els of credit risk, including the risk of default, depending on the nature of the particular government sup-port for that security. For example, a US government-sponsored entity, such as Federal National MortgageAssociation (“Fannie Mae”) or Federal Home Loan Mortgage Corporation (“Freddie Mac”), although char-tered or sponsored by an Act of Congress, may issue securities that are neither insured nor guaranteed bythe US Treasury and are therefore riskier than those that are.

Market risk: The risk that the market value of the fund’s investments may fluctuate, sometimes rapidly orunpredictably, as the markets fluctuate, which may affect the fund’s ability to maintain a $1.00 shareprice. Market risk may affect a single issuer, industry, or sector of the economy, or it may affect the mar-ket as a whole. Moreover, changing market, economic and political conditions in one country or geo-graphic region could adversely impact market, economic and political conditions in other countries orregions.

Interest rate risk: The value of the fund’s investments generally will fall when interest rates rise, and itsyield will tend to lag behind prevailing rates. The risks associated with rising interest rates may be morepronounced going forward due to the end of an extended period of historically low rates.

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Liquidity risk: Although the fund invests in a diversified portfolio of high quality instruments, the fund’sinvestments may become less liquid as a result of market developments or adverse investor perception.

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

PerformanceThere is no performance information quoted for the fund as the fund has not yet operated for a full calen-dar year as of the date of this prospectus.

Investment advisorUBS AM serves as the investment advisor to the fund.

Purchase & sale of fund sharesYou must be a client of UBS Financial Services Inc. or a client of certain affiliated firms to purchase fundshares. You may purchase or sell fund shares by contacting your Financial Advisor. The fund has a$5,000 minimum investment requirement for investors purchasing shares of the fund by withdrawingfrom certain deposit account sweep arrangements. The fund has no minimum to add to an account.Shares of the fund may be purchased or redeemed through your Financial Advisor on any business day onwhich the Boston offices of the fund’s custodian and the New York City offices of UBS Financial ServicesInc. and its bank are all open for business.

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

Payments to broker-dealers and other financial intermediariesIf you purchase the fund through a broker-dealer or other financial intermediary (such as a bank), the fundand its related companies may pay the intermediary for the sale of fund shares and related services. Thesepayments may create a conflict of interest by influencing the broker-dealer or other intermediary and yourfinancial advisor to recommend the fund over another investment. Ask your financial advisor or visit yourfinancial intermediary’s Web site for more information.

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More information about the fund

Additional information about the investmentobjectiveThe fund’s investment objective may not bechanged without shareholder approval.

Additional information about investmentstrategiesThe fund seeks to achieve its investment objectiveby investing in a diversified portfolio of high qual-ity, US government money market instrumentsand in related repurchase agreements, which gen-erally are short-term debt obligations and similarsecurities. They also may include longer-termbonds that have variable interest rates or otherspecial features that give them the financial char-acteristics of short-term debt. Many US govern-ment money market instruments pay income thatis generally exempt from state and local incometax, although they may be subject to corporatefranchise tax in some states. The fund may invest asignificant percentage of its assets in repurchaseagreements. Repurchase agreements are transac-tions in which the fund purchases governmentsecurities and simultaneously commits to resellthem to the same counterparty at a future timeand at a price reflecting a market rate of interest.Income from repurchase agreements may not beexempt from state and local income taxation.Repurchase agreements often offer a higher yieldthan investments directly in government securities.In deciding whether an investment in a repurchaseagreement is more attractive than a direct invest-ment in government securities, the fund considersthe possible loss of this tax advantage.

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

Therefore, the fund has adopted a policy to invest99.5% or more of its total assets in cash, govern-ment securities, and/or repurchase agreements thatare collateralized fully (i.e., collateralized with cashand/or government securities). As a “governmentmoney market fund,” the fund (1) is permitted touse the amortized cost method of valuation to seekto maintain a $1.00 share price, and (2) is not sub-ject to a liquidity fee and/or a redemption gate onfund redemptions which might apply to other typesof funds should certain triggering events specifiedin Rule 2a-7 occur. (In conformance with Rule 2a-7,the fund’s board has reserved its ability to changethis policy with respect to liquidity fees and/orredemption gates, but such change would onlybecome effective after shareholders were providedwith specific advance notice of a change in thefund’s policy and have the opportunity to redeemtheir shares in accordance with Rule 2a-7 beforethe policy change became effective.)

In addition, under normal circumstances, the fundinvests at least 80% of its net assets in US govern-ment securities, including government securitiessubject to repurchase agreements. The fund’s 80%policy is a “non-fundamental” policy. This meansthat this investment policy may be changed by thefund’s board without shareholder approval. How-ever, the fund has also adopted a policy to provideits shareholders with at least 60 days’ prior writtennotice of any change to the 80% investment policy.

Like all money market funds, the fund is subject tomaturity, quality, diversification and liquidity require-ments under Rule 2a-7. The fund’s investment strat-egies are designed to comply with these requirements.The fund may invest in high quality, short-term, USdollar-denominated money market instruments payinga fixed, variable or floating interest rate.

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UBS Money Series

UBS AM may use a number of professional moneymanagement techniques to respond to changingeconomic and money market conditions and toshifts in fiscal and monetary policy. These tech-niques include varying the fund’s composition andweighted average maturity based upon UBS AM’sassessment of the relative values of various moneymarket instruments and future interest rate pat-terns. UBS AM also may buy or sell money marketinstruments to take advantage of yield differences.

The master fund in which the fund invests maymaintain a rating from one or more rating agenciesthat provide ratings on money market funds. Therecan be no assurance that the master fund willmaintain any particular rating or maintain it with aparticular rating agency. To maintain a rating, UBSAM may manage the master fund more conserva-tively or differently than if it were not rated.

Additional information about principal risksThe main risks of investing in the fund aredescribed below.

Other risks of investing in the fund, along with fur-ther details about some of the risks describedbelow, are discussed in the fund’s Statement ofAdditional Information (“SAI”). Information on howyou can obtain the SAI can be found on the backcover of this prospectus.

Credit risk. Credit risk is the risk that the issuer ofa money market instrument will not make principalor interest payments when they are due. Even if anissuer does not default on a payment, a moneymarket instrument’s value may decline if the marketbelieves that the issuer has become less able, or lesswilling, to make payments on time. Even the high-est quality money market instruments are subject tosome credit risk. The credit quality of an issuer canchange rapidly due to market developments and

may affect the fund’s ability to maintain a$1.00 share price.

US Government securities risk. Credit risk is therisk that the issuer will not make principal or inter-est payments when they are due. There are differ-ent types of US government securities withdifferent relative levels of credit risk depending onthe nature of the particular government support forthat security. US government securities may besupported by (1) the full faith and credit of the US;(2) the ability of the issuer to borrow from the USTreasury; (3) the credit of the issuing agency, instru-mentality or government-sponsored entity; (4) poolsof assets (e.g., mortgage-backed securities); or(5) the US in some other way. In some cases, thereis even the risk of default. For example, for asset-backed securities there is the risk those assets willdecrease in value below the face value of the secu-rity. Similarly, for certain agency issued securitiesthere is no guarantee the US government will sup-port the agency if it is unable to meet its obliga-tions. Further, the US government and its agenciesand instrumentalities do not guarantee the marketvalue of their securities; consequently, the value ofsuch securities will fluctuate. This may be the caseespecially when there is any controversy or ongoinguncertainty regarding the status of negotiations inthe US Congress to increase the statutory debt ceil-ing. If the US Congress is unable to negotiate anadjustment to the statutory debt ceiling, there isalso the risk that the US government may defaulton payments on certain US government securities,including those held by the fund, which could havea material negative impact on the fund.

Interest rate risk. The value of money marketinstruments generally can be expected to fall whenshort-term interest rates rise and to rise when short-term interest rates fall. Interest rate risk is the riskthat interest rates will rise, so that the value of the

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fund’s investments will fall. Also, the fund’s yieldwill tend to lag behind changes in prevailing short-term interest rates. This means that the fund’sincome will tend to rise more slowly than increasesin short-term interest rates. Similarly, when short-term interest rates are falling, the fund’s incomegenerally will tend to fall more slowly.

The historically low interest rate environmentincreases the risk associated with rising interestrates, including the potential for periods of volatilityand increased redemptions. The fund may face aheightened level of interest rate risk since the USFederal Reserve Board has ended its quantitativeeasing program and may continue to raise rates.

Market risk. The market value of the fund’s invest-ments may fluctuate as the markets fluctuate. Mar-ket fluctuation may affect the fund’s ability tomaintain a $1.00 share price. Market risk, some-times dramatically or unpredictably, may affect asingle issuer, industry, section of the economy orgeographic region, or it may affect the market as awhole. Volatility of financial markets can expose thefund to greater market risk, possibly resulting ingreater illiquidity and valuation risks. Moreover,market, economic and political conditions in onecountry or geographic region could adversely impactmarket, economic and political conditions in othercountries or regions, including countries and regionsin which the fund invests, due to increasingly inter-connected global economies and financial markets.Additionally, market conditions and legislative, regu-latory, or tax developments may affect the invest-ment techniques available to the advisor inconnection with managing the fund and may resultin increased regulation of the fund or its invest-ments and, in turn, may adversely affect the abilityof the fund to achieve its investment objective andthe fund’s performance.

Liquidity risk. The fund’s investments may becomeless liquid due to market developments or adverseinvestor perception. When there is no willing buyerand investments cannot be readily sold at thedesired time or price, the fund may have to accepta lower price or may not be able to sell an instru-ment at all. The inability to sell an instrument couldadversely affect the fund’s ability to maintain a$1.00 share price or prevent the fund from beingable to take advantage of other investment oppor-tunities. This risk may increase during an unusuallyhigh volume of redemption requests by even a fewlarge investors or unusual market conditions.

Management risk. There is the risk that the invest-ment strategies, techniques and risk analysesemployed by the advisor may not produce thedesired results. The advisor may be incorrect in itsassessment of a particular security or assessment ofmarket, interest rate or other trends, which canresult in losses to the fund.

Additional (non-principal) risksSecurities lending risk. Securities lending involvesthe lending of portfolio securities owned by thefund to qualified broker-dealers and financial insti-tutions. When lending portfolio securities, the fundinitially will require the borrower to provide thefund with collateral, most commonly cash, whichthe fund will invest. Although the fund invests thiscollateral in a conservative manner, it is possiblethat it could lose money from such an investmentor fail to earn sufficient income from its investmentto cover the fee or rebate that it has agreed to paythe borrower. Loans of securities also involve a riskthat the borrower may fail to return the securitiesor deliver the proper amount of collateral, whichmay result in a loss to the fund. In addition, in theevent of bankruptcy of the borrower, the fundcould experience losses or delays in recovering theloaned securities. In some cases, these risks may be

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mitigated by an indemnification provided by thefund’s lending agent.

Temporary defensive positioning. Duringadverse market conditions or when the advisorbelieves there is an insufficient supply of appropri-ate money market securities in which to invest, the

fund may temporarily hold uninvested cash in lieuof such investments. During periods when suchtemporary or defensive positions are held, the fundmay not be able to fully pursue its investmentobjective. Such positions may also subject the fundto additional costs and risks, such as increasedexposure to cash held at a custodian bank.

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Managing your fund account

Buying SharesIntroduction. You must be a client of UBS Finan-cial Services Inc. or a client of a UBS Financial Ser-vices Inc. correspondent firm to purchase fundshares. Shares of the funds are available primarilythrough the UBS Financial Services Inc. ResourceManagement Account® (RMA®) Program, the UBSFinancial Services Inc. Business Services Account(BSA®) Program, the UBS Financial Services Inc.Basic Investment Account Program and certain UBSFinancial Services Inc. advisory programs.

The RMA and Business Services Account BSA pro-grams are more fully described in separate materialsyour Financial Advisor can provide you (the “UBSAccount Agreements”). Not all correspondent firmshave arrangements with UBS Financial Services Inc.to make fund shares available to their customers.

Automatic sweep programs. UBS Financial Ser-vices Inc. administers bank deposit sweep programsunder which free cash balances in certain clientsecurities accounts are automatically swept intointerest-bearing deposit accounts at UBS affiliatedbanks and non-affiliated banks (the “Bank SweepPrograms”). The terms and eligibility requirementsfor the Bank Sweep Programs are described in theUBS Bank Sweep Programs Disclosure Statementand the UBS FDIC-Insured Deposit Program Disclo-sure Statement (collectively, the “DisclosureStatements”), which are part of the UBS AccountAgreements.

Investors who are eligible to participate in the BankSweep Programs are referred to as “eligible partici-pants” below to distinguish them from other inves-tors in the fund.

Free cash balances (that is, immediately availablefunds) of certain eligible participants automatically

default to one or more interest-bearing depositaccounts (based on account type) as a primarysweep option.

Accounts participating in the Bank Sweep Programsare generally subject to an automatic dollar limit or“cap,” which will apply to the amount that can beswept into bank deposit accounts under the appli-cable Bank Sweep Program (cap levels may vary perBank Sweep Program). Available balances in excessof a program’s cap will be automatically invested ina “secondary sweep option,” which may be depositaccounts at UBS AG (Stamford Branch) or an avail-able money market fund, including this fund.

Certain non-eligible participants may be eligible tohave free cash balances in their securities accountsautomatically invested in shares of this fund as their“primary sweep option.” Please refer to the UBSAccount Agreements for more information.

Selecting and changing your sweep option.Please refer to the UBS Account Agreements forinformation on available sweep options, includingrestrictions and eligibility requirements. If youwould like to change your sweep option, pleasecontact your Financial Advisor at UBS Financial Ser-vices Inc.

Background information. Your order to purchasethe fund’s shares will be effective on the business dayon which federal funds become available to the fund.Federal funds are funds deposited by a commercialbank in an account at a Federal Reserve Bank thatcan be transferred to a similar account of anotherbank in one day and thus can be made immediatelyavailable to the fund. A business day is any day thatthe Boston offices of the fund’s custodian and theNew York City offices of UBS Financial Services Inc.

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UBS Money Series

and its bank are all open for business. One or moreof these institutions will be closed on the observanceof the following holidays: New Year’s Day, MartinLuther King, Jr. Day, Presidents’ Day, Good Friday,Memorial Day, Independence Day, Labor Day,Columbus Day, Veterans Day, Thanksgiving Day andChristmas Day.

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

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

Buying shares automaticallyNon-eligible participants. All free cash balancesin securities accounts of $1.00 or more (or for IRAs,of $0.01 or more), including proceeds from thesecurities you have sold, are automatically investedin your sweep option on a daily basis for settlementthe same day.

(Federal funds normally are available to be sweptinto your sweep option on the next business day.Federal funds availability can sometimes take longerfor cash balances arising from the sale of securitiesin your brokerage account.)

Fund shares will be purchased only after all debitsand charges to your brokerage account are satis-fied. See “Selling shares automatically” below.

Eligible participants for the Bank Sweep Pro-grams. Please refer to the Disclosure Statementsfor more information about eligible participants inthe Bank Sweep Programs.

Buying shares by check or electronic fundstransfer credit. RMA and Business Service AccountBSA participants may purchase shares of, as applica-ble, their primary sweep money fund or anotherfund by placing an order with their Financial Advisorand providing a check from a US bank. You shouldinclude your UBS Financial Services Inc. accountnumber on the check. Only non-eligible participants(and eligible participants who are purchasing fundshares in excess of the automatic dollar limit cap oninvestments in a Bank Sweep Program) may buyshares by check or electronic funds transfer credit.

Federal funds are deemed available to a fund twobusiness days after the deposit of a personal checkor an Electronic Funds Transfer credit initiated byUBS Financial Services Inc. and one business dayafter deposit of a cashier’s or certified check. UBSFinancial Services Inc. may benefit from the tempo-rary use of the proceeds of personal checks andElectronic Funds Transfer credits if they are con-verted to federal funds in less than two businessdays.

Buying shares by wire. You may purchase fundshares by placing an order through your FinancialAdvisor and instructing your bank to transferfederal funds by wire to:

UBS AGABA 026007993UBS Financial Services Inc.—RMAA/C 101WA258640000Account Name/Brokerage Account Number

The wire must include your name and UBS FinancialServices Inc. brokerage account number. Only non-eligible participants (and eligible participants whoare purchasing fund shares in excess of the auto-matic dollar limit cap on investments in a BankSweep Program) may buy shares by wire.

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If UBS Financial Services Inc. receives funds in theaccount for a purchase of fund shares by 12:00noon, Eastern time, on a business day, UBS FinancialServices Inc. will execute the purchase on that day.Otherwise, UBS Financial Services Inc. will executethe order on the next business day. UBS FinancialServices Inc. and/or your bank may impose a servicecharge for wire transfers/purchases.

Buying shares of the fund by certain eligibleparticipants. Certain eligible participants maywithdraw available balances in the Bank Sweep Pro-grams in order to directly purchase shares of thefund. The fund has a $5,000 minimum investmentrequirement for such purchases. For more informa-tion, please contact your Financial Advisor at UBSFinancial Services Inc.

Minimum investment. The fund has no minimumfor initial investments or to add an account, butreserves the right to establish minimum investmentrequirements at any time.

Additional compensation to affiliated dealerUBS AM has entered into an agreement with itsaffiliate, UBS Financial Services Inc., under whichUBS AM (or its affiliate UBS Asset Management(US) Inc., the fund’s distributor (“UBS AM (US)”))pays UBS Financial Services Inc. additional compen-sation in connection with the sale of fund sharesand the provision of administrative and shareholderservices.

The aggregate amount of these payments may besubstantial and may represent a significant portionof the advisory and administrative fees charged byUBS AM. These payments do not increase theexpenses of a fund, but are made by UBS AM (or itsaffiliate UBS AM (US)) out of its own legitimateprofits or other resources. The payments mayinclude amounts that are sometimes referred to as“revenue sharing” payments.

Selling sharesYou may sell your shares by contacting your Finan-cial Advisor in person or by telephone or mail. Youmay also be able to use the check-writing service tosell your shares, where applicable. You may notclose your account by check.

Your sales proceeds will be paid in federal funds ordi-narily on the same day. If you sell all the shares youown, dividends accrued for the month to date will bepaid in federal funds and wired or deposited intoyour account on the same day.

Typically, redemptions of fund shares will be madeby the fund wiring a cash payment or deposit intoyour account. The fund typically expects to meetredemption requests by using holdings of cash orcash equivalents and/or proceeds from the sale ormaturity of portfolio holdings. However, if conditionsexist that make cash payments undesirable, the fundreserves the right to honor any request for redemp-tion by making payments in whole or in part in secu-rities, to the extent permitted under applicable law.

Selling shares automatically. Subject to, and inthe order described in, the terms of the UBSAccount Agreements, your fund shares will be soldautomatically to settle any outstanding securitiespurchases, charges or other debits to your UBSFinancial Services Inc. securities account, unless youinstruct your Financial Advisor otherwise.

More information regarding “EligibleParticipants.” For eligibility requirements for theBank Sweep Programs, please refer to the Disclo-sure Statements.

Additional information regarding sweep options forinvestors participating in the PACESM Select AdvisorsProgram and PACESM Multi Advisor Program: Theseprograms may provide for an allocation to anothermoney market fund as part of an investment allocation

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plan; however, since your PACE investment is heldwithin a UBS Financial Services brokerage account(e.g., an RMA account, a basic investment account,etc.), available cash balances in the brokerage portionof RMA accounts and basic investment accounts areautomatically swept to the applicable Bank Sweep Pro-gram in accordance with the terms of your brokerageaccount agreement, which terms differ from thoseapplicable to advisory accounts.

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

Temporary sweep option. If you are an eligibleparticipant, in the event that the bank offering theinterest-bearing deposit accounts into which yourfree cash balances are swept elects to stop takingdeposits at its discretion or if it is prohibited fromdoing so by its banking regulators, your free cashbalances will be swept to a temporary sweepoption. The fund will be a temporary sweep optionfor certain eligible participants. Please refer to theDisclosure Statements for more information regard-ing the temporary sweep option and how it may beimplemented.

Additional information about your account. Itcosts the fund money to maintain shareholderaccounts. Therefore, the fund reserves the right torepurchase all shares in any account that has a netasset value of less than $500. If the fund elects todo this with your account, it will notify you that youcan increase the amount invested to $500 or morewithin 60 days. This notice may appear on youraccount statement. Participants in a Bank SweepProgram who wish to increase their fund accountbalance to $500 or more will need to add sufficientcash to their securities accounts so that the BankSweep Program cap and this minimum are bothmet. If the Bank Sweep Program cap and fund min-imum are not met, the proceeds from the sale of

fund shares will be deposited in the investor’s secu-rities account and swept into one or more bankdeposit accounts until the program cap is reached.

If you want to sell shares that you purchasedrecently, a fund may delay payment to assure that ithas received good payment. If you purchasedshares by check, this can take up to 15 days.

UBS Financial Services Inc. has the right to termi-nate your securities account for any reason. In thatcase, UBS Financial Services Inc. will sell all of thefund shares held in the account and will send youthe proceeds within three business days.

To help the government fight the funding of terror-ism and money laundering activities, federal lawrequires all financial institutions to obtain, verifyand record information that identifies each personwho opens an account. If you do not provide theinformation requested, the fund may not be able tomaintain your account. If the fund is unable to ver-ify your identity or that of another person(s) autho-rized to act on your behalf, the fund and UBS AM(US) reserve the right to close your account and/ortake such other action they deem reasonable orrequired by law. Fund shares will be redeemed andvalued in accordance with the net asset value nextcalculated after the determination has been madeto close the account.

You will receive confirmation of your purchases andsales of fund shares on periodic account state-ments. These periodic statements may be sentmonthly except that, if your only fund activity in aquarter was reinvestment of dividends, the activitymay be reported on a quarterly rather than amonthly statement.

Upon receipt of a proper redemption request sub-mitted in a timely manner and otherwise in accor-dance with the redemption procedures set forth in

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this prospectus, the fund will redeem the requestedshares and make a payment. The fund may post-pone and/or suspend redemption and paymentbeyond one business day (but within seven calendardays) for any period during which there is a non-routine closure of the Fedwire or applicable FederalReserve Banks. In addition, the fund may also post-pone or suspend redemption and payment as fol-lows: (1) for any period (a) during which the NewYork Stock Exchange (“NYSE”) is closed other thancustomary weekend and holiday closings or(b) during which trading on the NYSE is restricted;(2) for any period during which an emergency existsas a result of which (a) disposal by the fund ofsecurities owned by it is not reasonably practicableor (b) it is not reasonably practicable for the fundfairly to determine the net asset value of shares ofthe fund; (3) for any period during which the SEChas, by rule or regulation, deemed that (a) tradingshall be restricted or (b) an emergency exists; (4) forany period that the SEC may by order permit foryour protection; or (5) for any period during whichthe fund, as part of a necessary liquidation of thefund, has properly postponed and/or suspendedredemption of shares and payment in accordancewith federal securities laws.

Please note that additional fees may apply foroptional RMA/Business Services Account BSA pro-gram services. Please refer to the UBS AccountAgreements or speak with your Financial Advisor forinformation regarding program fees.

Market timing. Frequent purchases and redemp-tions of fund shares could increase the fund’s trans-action costs, such as market spreads and custodialfees, and may interfere with the efficient manage-ment of the fund’s portfolio, which could impactthe fund’s performance. However, money marketfunds are generally used by investors for short-terminvestments, often in place of bank checking or sav-ings accounts or for cash management purposes.

Investors value the ability to add and withdraw theirfunds quickly, without restriction. UBS AM (US)anticipates that shareholders will purchase and sellfund shares frequently because the fund isdesigned to offer investors a liquid cash option.

UBS AM (US) also believes that money marketfunds, such as the fund offered in this prospectus,are not targets of abusive trading practices. Forthese reasons, the fund’s board has not adoptedpolicies and procedures, or imposed redemptionfees or other restrictions such as minimum holdingperiods, to discourage excessive or short-term trad-ing of fund shares.

Other UBS funds that are managed by UBS AM thatare not money market funds have approved policiesand procedures designed to discourage and preventabusive trading practices. For more informationabout market timing policies and procedures forthese funds, please see the funds’ prospectuses.

Pricing and valuationThe price of fund shares is based on net asset value.The net asset value per share is equal to the valueof all the assets of the fund, minus the liabilities ofthe fund divided by the number of shares outstand-ing. In determining net asset value, the master fundvalues its securities at their amortized cost (unlessthe fund’s board (or its delegate) determines thatthis does not represent fair value), and the fundbuys the master fund’s interests at the masterfund’s net asset value. The amortized cost methoduses a constant amortization to maturity of the dif-ference between the cost of the instrument to thefund and the amount due at maturity. The fund’snet asset value per share is expected to be $1.00,although this value is not guaranteed.

The fund typically calculates net asset value pershare once each business day as of 12:00 noon,Eastern time. Your price for buying or selling shares

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UBS Money Series

will be the net asset value that is next calculatedafter the fund receives your order in good form.

Your Financial Advisor is responsible for makingsure that your order is promptly sent to the fundwhen shares are purchased other than through theautomatic program described above.

The fund’s board has delegated to a UBS AM valua-tion committee the responsibility for making fairvalue determinations with respect to the fund’sportfolio securities. The types of securities andother instruments for which such fair value pricingmay be necessary include, but are not limited to:securities of an issuer that has entered into arestructuring; fixed-income securities that havegone into default and for which there is no currentmarket value quotation; Section 4(a)(2) commercialpaper; securities or instruments that are restrictedas to transfer or resale; illiquid instruments; andinstruments for which the prices or values availabledo not, in the judgment of UBS AM, represent cur-rent market value. The need to fair value the fund’sportfolio securities may also result from low tradingvolume in foreign markets or thinly traded securitiesor instruments. Various factors may be reviewed inorder to make a good faith determination of asecurity’s or instrument’s fair value. These factorsinclude, but are not limited to, fundamental analyti-cal data relating to the investment; the nature andduration of restrictions on disposition of the securi-ties or instruments; and the evaluation of forceswhich influence the market in which the securitiesor instruments are purchased and sold.

The fund’s portfolio holding consists of an interest inthe master fund in which the fund invests. The valueof such portfolio holding reflects the fund’sproportionate interest in the net assets of the masterfund. The master fund generally values securities andother instruments in a manner as described in themaster fund’s prospectus or similar document.

ManagementInvestment advisorUBS Asset Management (Americas) Inc. (“UBS AM”)acts as the investment advisor and administrator forGovernment Master Fund which is the master fund inwhich the fund invests its assets. UBS AM also acts asthe administrator for the fund. As investment advisor,UBS AM makes the master fund’s investment deci-sions. It buys and sells securities for the master fundand conducts the research that leads to the purchaseand sale decisions.

UBS AM is a Delaware corporation with its principalbusiness offices located at One North Wacker Drive,Chicago, IL 60606 and at 1285 Avenue of theAmericas, New York, New York, 10019-6028. UBSAM is an investment advisor registered with the SEC.UBS AM is an indirect asset management subsidiaryof UBS Group AG (“UBS”). As of June 30, 2017, UBSAM had approximately $155.7 billion in assets undermanagement. UBS AM is a member of the UBS AssetManagement Division, which had approximately$732.2 billion in assets under management world-wide as of June 30, 2017. UBS is an internationallydiversified organization headquartered in Zurich,Switzerland and with operations in many areas ofthe financial services group of industries.

Advisory and administration feesUBS AM’s contract fee for the advisory and admin-istrative services it provides to the Master Fund isbased on the following fee schedule:

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

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UBS Money Series

UBS AM’s contract fee for the administrative ser-vices it provides to the fund is 0.10% of the fund’saverage daily net assets.

UBS AM received an effective fee of 0.16% of theaverage daily net assets of the fund for its services inthe fund’s last fiscal period which ended April 30,2017 (includes fees allocated from related MasterFund, net of voluntary fee waivers/expense reim-bursements, if any). The effective fee for the fundreflects voluntary waivers.

UBS AM may voluntarily waive fees and/or reimburseexpenses from time to time. For example, UBS AMmay voluntarily undertake to waive fees and/or reim-burse expenses in the event that fund yields dropbelow a certain level. Once started, there is no guar-antee that UBS AM would continue to voluntarilywaive a portion of its fees and/or reimburseexpenses. Waivers/reimbursements may impact afund’s performance.

A discussion regarding the basis for the masterfund’s board’s approval of the Management Agree-ment between UBS AM and Master Trust withrespect to the master fund is available in the fund’ssemiannual report to shareholders for the fiscalperiod ended October 31, 2016.

Master-feeder structureThe fund is a “feeder fund” that invests all of itsassets in a “master fund”—Government MasterFund. The fund and the master fund have the sameinvestment objective.

The master fund may accept investments from otherfeeder funds. Each feeder fund bears the masterfund’s expenses in proportion to its investment in themaster fund. Each feeder fund can set its own trans-action minimums, feeder fund-specific expenses andother conditions. This arrangement allows each

feeder fund’s trustees to withdraw the feeder fund’sassets from the master fund if they believe doing sois in the shareholders’ best interests. If the trusteeswithdraw the feeder fund’s assets, they would thenconsider whether the feeder fund should hire itsown investment advisor, invest in a different masterfund or take other action.

Other informationTo the extent authorized by law, the fund reservesthe right to discontinue offering shares at any timemerge, reorganize itself or cease operations andliquidate.

Dividends and taxesDividendsThe fund declares dividends daily and pays themmonthly. Dividends accrued during a given monthare paid on the first business day of the next monthor upon the sale of all the fund shares in a share-holder’s account.

The fund may distribute all or a portion of its capitalgains (if any) to the extent required to ensure thatthe fund maintains its federal tax law status as aregulated investment company. The fund will alsodistribute all or a portion of its capital gains to theextent necessary to maintain its share price at $1.00.

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

You will receive dividends in additional sharesunless you elect to receive them in cash. If you pre-fer to receive dividends in cash, contact your Finan-cial Advisor.

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UBS Money Series

While the fund declares dividends daily and paysthem monthly, the amounts are rounded to thenearest $0.01 on a daily basis with respect to eachinvestor’s fund account. As a result, investorswhose fund account balances earn daily dividendsthat total less than one half a cent on any given daywill not accrue any dividends on that day.

TaxesThe dividends that you receive from the fund gen-erally are subject to federal income tax regardless ofwhether you receive them in additional fund sharesor in cash, and are expected to be taxed as ordinaryincome. Such dividends are not eligible for thereduced rate of tax that may apply to certain quali-fying dividends on corporate stock.

Although dividends are generally treated as taxableto you in the year they are paid, dividends declaredin October, November or December but paid inJanuary are taxable as if they were paid inDecember.

Shareholders not subject to tax on their income willnot be required to pay tax on amounts distributedto them. If you hold fund shares through a tax-exempt account or plan such as an IRA or401(k) plan, dividends on your shares generally willnot be subject to tax until proceeds are withdrawnfrom the plan.

Some states and localities do not tax dividends thatare attributable to interest on certain governmentsecurities under certain circumstances. However,these dividends may be subject to corporate fran-chise tax in some states.

The fund will tell you annually the character of divi-dends for tax reporting purposes. You will generallynot recognize any gain or loss on the sale orexchange of your fund shares as long as the fundmaintains a share price of $1.00.

An additional 3.8% Medicare tax is imposed on cer-tain net investment income (including ordinary divi-dends and capital gain distributions received fromthe fund and net gains from redemptions or othertaxable dispositions of fund shares) of U.S. individu-als, estates and trusts to the extent that such per-son’s “modified adjusted gross income” (in the caseof an individual) or “adjusted gross income” (in thecase of an estate or trust) exceeds certain thresholdamounts.

The fund may be required to withhold a 28%federal tax on all dividends payable to you

• if you fail to provide the fund with your correcttaxpayer identification number on Form W-9 (forUS citizens and resident aliens) or to makerequired certifications, or

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

Taxable distributions to non-residents will generallybe subject to a 30% withholding tax (or lowerapplicable treaty rate).

The fund is required to withhold US tax (at a 30%rate) on payments of taxable dividends and (effec-tive January 1, 2019) redemption proceeds and cer-tain capital gains dividends made to certain non-USentities that fail to comply (or be deemed compli-ant) with extensive new reporting and withholdingrequirements designed to inform the US Depart-ment of the Treasury of US-owned foreign invest-ment accounts. Shareholders may be requested toprovide additional information to the fund toenable the fund to determine whether withholdingis required.

The above is a general and abbreviated discussionof certain tax considerations, and each investor is

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UBS Money Series

advised to consult with his or her own tax advisor.There is additional information on taxes in thefund’s SAI.

Disclosure of portfolioholdings and otherinformationThe fund is a “feeder fund” that invests in securi-ties through an underlying master fund. The fundand the master fund have the same investmentobjective.

The fund will file its complete schedule of portfolioholdings with the SEC for the first and third quar-ters of each fiscal year on Form N-Q. The fund’scomplete schedule of portfolio holdings for the sec-ond and fourth quarters of each fiscal year will beincluded in its semiannual and annual reports toshareholders and will be filed with the SEC onForm N-CSR. The fund’s Forms N-Q andForms N-CSR are available on the SEC’s Web site athttp://www.sec.gov. The fund’s Forms N-Q andForms N-CSR may also be reviewed and copied atthe SEC’s Public Reference Room in Washington,D.C. Information on the operation of the SEC’sPublic Reference Room may be obtained by calling1-202-551 8090. Additionally, you may obtain cop-ies of Forms N-Q and semiannual and annualreports to shareholders from the fund upon requestby calling 1-800-647 1568. The semiannual andannual reports for the fund will be posted on thefund’s Web site athttps://www.ubs.com/usmoneymarketfunds.

The fund will disclose on UBS AM’s Web site, withinfive business days after the end of each month, acomplete schedule of the Master Fund’s portfolioholdings and information regarding the weightedaverage maturity and weighted average life of theMaster Fund. This information will be posted on theUBS Web site at the following internet address:https://www.ubs.com/usmoneymarketfunds. In addi-tion, the fund will file with the SEC on Form N-MFP,within five business days after the end of eachmonth, more detailed portfolio holdings information.The fund’s Forms N-MFP will be available on theSEC’s Web site; UBS AM’s Web site will also containa link to these filings. The UBS AM Web site will alsodisclose the following information for the fund as ofthe end of each business day for the previous sixmonths: (1) the percentage of the fund’s total assetsinvested in daily and weekly liquid assets; (2) thefund’s daily net inflows and outflows; and (3) thefund’s current market-based net asset value pershare to four decimal places, which is calculatedusing current market quotations (or an appropriatesubstitute that reflects current market conditions).(For purposes of transactions in shares of the fund,the price for shares will be the net asset value pershare, calculated using the amortized cost method totwo decimal places as further described in this pro-spectus and the related SAI.) Investors also may findadditional information about the fund at the abovereferenced UBS Web site internet address.

Please consult the fund’s SAI for a description ofthe policies and procedures that govern disclosureof the fund’s portfolio holdings.

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UBS Money Series

Financial highlights

The following financial highlights table is intendedto help you understand the financial performancefor the fund since it commenced operations onJune 24, 2016, through April 30, 2017. Certaininformation reflects financial results for a singlefund share. In the table, “total investment return”represents the rate that an investor would haveearned on an investment in a fund (assuming rein-vestment of all dividends and other distributions).

The information in the financial highlights has beenderived from the financial statements audited byErnst & Young LLP, an independent registered pub-lic accounting firm, whose report appears in theAnnual Report to Shareholders of the fund. Youmay obtain copies of the fund’s Annual Reportwithout charge by calling 1-888-647 1568.

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

For theperiod from

June 24, 20161 toApril 30, 2017

Net asset value, beginning of period $1.00

Net investment income 0.001Net realized gains 0.0002

Net increase from operations 0.001

Dividends from net investment income (0.001)Distributions from net realized gains (0.000)2

Total dividends and distributions (0.001)

Net asset value, end of period $1.00

Total investment return3 0.07%

Ratios to average net assets:Expenses before fee waivers and/or expense reimbursements4 0.48%5

Expenses after fee waivers and/or expense reimbursements4 0.41%5

Net investment income4 0.08%5

Supplemental data:Net assets, end of period (OOO’s) $8,216,903

1 Commencement of operations.2 Amount represents less than $0.0005 per share.3 Total investment return is calculated assuming a $10,000 investment on the first day of the period reported, reinvestment of all dividends and other distri-

butions, if any, at net asset value on the payable dates, and a sale at net asset value on the last day of the period reported. Total investment return for theperiod 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.

4 Ratios include the fund’s share of income, expenses and expense waivers allocated from Government Master Fund.5 Annualized.

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UBS Money Series

Privacy noticeThis privacy notice is not a part of the prospectus.

UBS family of funds privacy notice

This notice describes the privacy policy of the UBS Family of Funds and the PACE® Funds managed by UBSAsset Management (collectively, the “Funds”). The Funds are committed to protecting the personal infor-mation that they collect about individuals who are prospective, current or former investors.

The Funds collect personal information in order to process requests and transactions and to provide cus-tomer service. Personal information, which is obtained from applications and other forms or correspon-dence submitted to the Funds, may include name(s), address, e-mail address, telephone number, date ofbirth, social security number or other tax identification number, bank account information, informationabout your transactions and experiences with the Funds, and any affiliation a client has with UBS FinancialServices Inc. or its affiliates (“Personal Information”).

The Funds limit access to Personal Information to those individuals who need to know that information inorder to process transactions and service accounts. These individuals are required to maintain and protectthe confidentiality of Personal Information and to follow established procedures. The Funds maintain phys-ical, electronic and procedural safeguards to protect Personal Information and to comply with applicablelaws and regulations.

The Funds may share Personal Information with their affiliates to facilitate the servicing of accounts and forother business purposes, or as otherwise required or permitted by applicable law. The Funds may alsoshare Personal Information with non-affiliated third parties that perform services for the Funds, such asvendors that provide data or transaction processing, computer software maintenance and development,and other administrative services. When the Funds share Personal Information with a non-affiliated thirdparty, they will do so pursuant to a contract that includes provisions designed to ensure that the thirdparty will uphold and maintain privacy standards when handling Personal Information. In addition to shar-ing information with non-affiliated third parties to facilitate the servicing of accounts and for other busi-ness purposes, the Funds may disclose Personal Information to non-affiliated third parties as otherwiserequired or permitted by applicable law. For example, the Funds may disclose Personal Information tocredit bureaus or regulatory authorities to facilitate or comply with investigations; to protect against orprevent actual or potential fraud, unauthorized transactions, claims or other liabilities; or to respond tojudicial or legal process, such as subpoena requests.

Except as described in this privacy notice, the Funds will not use Personal Information for any other pur-pose unless the Funds describe how such Personal Information will be used and clients are given an oppor-tunity to decline approval of such use of Personal Information relating to them (or affirmatively approvethe use of Personal Information, if required by applicable law). The Funds endeavor to keep their customerfiles complete and accurate. The Funds should be notified if any Personal Information needs to be cor-rected or updated. Please call 1-800-647 1568 with any questions or concerns regarding your PersonalInformation or this privacy notice.

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UBS Money Series

UBS Asset Management, Americas Region

Business continuity planning overview

UBS Asset Management affiliates UBS Asset Management (US) Inc. and UBS Asset Management(Americas) Inc. protect information assets, processes, and customer data from unpredictable eventsthrough preparation and testing of a comprehensive business continuity capability. This capability seeksrecovery of the technology infrastructure and information, and prevention of the loss of company or cus-tomer information and transactions. In the event of a crisis scenario, we will recover those functionsdeemed to be critical to our business and our clients, and strive to resume processing within predefinedtime frames following a disaster declaration (typically 4-6 hours). Business continuity processes provide usthe ability to continue critical business functions regardless of the type, scope, or duration of a localizedevent. However, these processes are dependent upon various external resources beyond our control, suchas regional telecommunications, transportation networks, and other public utilities.

Essential elements of the business continuity plan include:

• Crisis communication procedures—Action plans for coordinating essential communications for crisismanagement leaders, employees, and key business partners

• Information technology backup and recovery procedures—Comprehensive technology and datamanagement plans designed to protect the integrity and quick recovery of essential technology infra-structure and data

• Disaster recovery site—Alternative dedicated workspace, technology infrastructure, and systems sup-port that is designed to be fully operational within 2-4 hours of a disaster declaration

• Testing regimen—The business continuity plan is reviewed on a quarterly basis and tested on anannual basis, including full activation of the disaster recovery facility. In addition, all IT application recov-ery plans are updated and tested annually.

This business continuity planning overview is not a part of the prospectus.

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

Annual/semiannual reportsAdditional information about the fund’s investments isavailable in the fund’s annual and semiannual reports toshareholders.

Statement of Additional Information (SAI)The fund’s SAI provides more detailed information about thefund 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 contactingyour Financial Advisor. You may obtain free copies of the fund’sannual and semiannual reports and its SAI by contacting the funddirectly at 1-800-647 1568. The fund’s annual and semiannualreports and its SAI will also be posted on the UBS Web site at thefollowing internet address:https://www.ubs.com/usmoneymarketfunds. You may alsorequest other information about the fund and make shareholderinquiries via the telephone number above.

You will be able to review and copy information about thefund, including shareholder reports and the SAI, at the PublicReference Room of the Securities and Exchange Commission.You may obtain information about the operations of the SEC’sPublic Reference Room by calling the SEC at 1-202-551 8090.You can get copies of reports and other information about thefund:

• For a fee, by electronic request at publicinfo@sec.gov or bywriting the SEC’s Public Reference Section, Washington,D.C. 20549-1520; or

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

UBS Money Series—UBS RMA Government Money Market FundInvestment Company Act File No. 811-08767©UBS 2017. All rights reserved.S1631

UBS RMA GovernmentMoney Market FundProspectus | August 28, 2017