prospectus - treasury portfolio - dws u.s. - dws investments

SUPPLEMENTTOTHE CURRENTLY EFFECTIVE CLASS S PROSPECTUSES OF EACH OFTHE LISTED FUNDS

DWS CaliforniaTax-Free Income FundDWS Capital Growth FundDWS Core Equity FundDWS CROCI ® Equity Dividend FundDWS CROCI ® International FundDWS CROCI ® U.S. FundDWS Emerging Markets Equity FundDWS Emerging Markets Fixed Income FundDWS Enhanced Commodity Strategy FundDWS Equity 500 Index FundDWS European Equity FundDWS Fixed Income Opportunities FundDWS Floating Rate FundDWS Global High Income FundDWS Global Income Builder FundDWS Global Macro FundDWS Global Small Cap FundDWS GNMA Fund

DWS Health and Wellness FundDWS High Conviction Global Bond FundDWS High Income FundDWS IntermediateTax-Free FundDWS International Growth FundDWS Large Cap Focus Growth FundDWS Latin America Equity FundDWS Managed Municipal Bond FundDWS MassachusettsTax-Free FundDWS Mid Cap Value FundDWS Money Market Prime SeriesDWS Multi-Asset Conservative Allocation

FundDWS Multi-Asset Global Allocation FundDWS Multi-Asset Moderate Allocation FundDWS Multisector Income FundDWS NewYorkTax-Free Income FundDWS RREEF Global Infrastructure Fund

DWS RREEF Global Real Estate SecuritiesFund

DWS RREEF MLP & Energy InfrastructureFund

DWS RREEF Real Assets FundDWS RREEF Real Estate Securities FundDWS S&P 500 Index FundDWS Science andTechnology FundDWS Short Duration FundDWS Short Duration High Income FundDWS Short-Term Municipal Bond FundDWS Small Cap Core FundDWS Small Cap Growth FundDWS Strategic HighYieldTax-Free FundDWSTax-Exempt PortfolioDWSTotal Return Bond FundDWSTreasury PortfolioDWS World Dividend Fund

The following changes are effective on or about February 11, 2019:

The following disclosure is added to the first paragraph under the “Fees and Expenses of the Fund” section of each fund’ssummary section of the prospectus.

You may be required to pay commissions and/or other forms of compensation to a broker for transactions in Class S shares,which are not reflected in the tables or the example below.

The following disclosure is added to the paragraph under the table in the “MINIMUM INITIAL INVESTMENT” sub-heading ofthe “PURCHASE AND SALE OF FUND SHARES” section of each fund’s summary section of the prospectus.

Certain intermediaries that offer Class S shares in their brokerage platforms may be eligible for an investment minimumwaiver.

The following information replaces the last sentence under the “TO PLACE ORDERS” sub-heading of the “PURCHASE ANDSALE OF FUND SHARES” section of each fund’s summary section of the prospectus.

Class S shares are only available to a limited group of investors as well as through firms with brokerage platforms that canoffer the shares on an agency basis.

The following disclosure is added in the “Class S Shares – Eligibility Requirements” subsection of the “CHOOSING A SHARECLASS” section in each fund’s prospectus:

Class S shares may also be available on brokerage platforms of firms that have agreements with DWS Distributors, Inc. tooffer such shares when acting solely on an agency basis for its customers for the purchase or sale of such shares. If youtransact in Class S shares through one of these programs, you may be required to pay a commission and/or other forms ofcompensation to your broker. Shares of a fund are available in other share classes that have different fees and expenses.

The following disclosure is added in the “Class S Shares” subsection of the “CHOOSING A SHARE CLASS” section in eachfund’s prospectus:

Investment Minimum

The minimum initial investment is waived for:� Eligible intermediaries that have agreements with DWS Distributors, Inc. to offer Class S shares in their brokerage plat-

forms when such Class S shares are held in omnibus accounts on such brokerage platforms.

Please Retain This Supplement for Future Reference

December 6, 2018PROSTKR-1095

ProspectusAugust 1, 2018

DWSTreasury Portfolio(formerly DeutscheTreasury Portfolio)

CLASS/TICKER

DWS U.S.TREASURY MONEY FUNDCLASS S(formerly DEUTSCHE U.S. TREASURY MONEY FUNDCLASS S) IUSXX

As with all mutual funds, the Securities and Exchange Commission (SEC) does not approve or disapprovethese shares or determine whether the information in this prospectus is truthful or complete. It is a criminaloffense for anyone to inform you otherwise.

Table of Contents

DWS TREASURY PORTFOLIO

Investment Objective. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Fees and Expenses of the Fund . . . . . . . . . . . . . . . . . . . . . 1Principal Investment Strategy . . . . . . . . . . . . . . . . . . . . . . . 1Main Risks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Past Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Purchase and Sale of Fund Shares. . . . . . . . . . . . . . . . . . . 3Tax Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Payments to Broker-Dealers andOther Financial Intermediaries. . . . . . . . . . . . . . . . . . . . . . . 3

FUND DETAILS

Additional Information About Fund Strategies andRisks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Other Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Who Manages and Oversees the Fund . . . . . . . . . . . . . . 7Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

INVESTING IN THE FUND

Buying, Exchanging and Selling Shares . . . . . . . . . . . . . . 9How to Buy Shares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9How to Exchange Shares . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10How to Sell Shares . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Financial Intermediary Support Payments . . . . . . . . . . . 11Policies You Should Know About . . . . . . . . . . . . . . . . . . . . . 12Policies About Transactions . . . . . . . . . . . . . . . . . . . . . . . . . . 12How the Fund Calculates Share Price . . . . . . . . . . . . . . . 15Other Rights We Reserve . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Understanding Distributions and Taxes . . . . . . . . . . . . . . 15

FINANCIAL HIGHLIGHTS . . . . . . . . . . . . . . . . . . . . . . 18

APPENDIX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Hypothetical Expense Summary. . . . . . . . . . . . . . . . . . . . . 19

YOUR INVESTMENT IN THE FUND IS NOT A BANK DEPOSIT AND IS NOT INSURED OR GUARANTEED BY THEFEDERAL DEPOSIT INSURANCE CORPORATION OR ANY OTHER GOVERNMENT AGENCY, ENTITY OR PERSON.

DWSTreasury Portfolio(formerly DeutscheTreasury Portfolio)

INVESTMENT OBJECTIVE

The fund seeks to provide maximum current incomeconsistent with stability of capital.

FEES AND EXPENSES OF THE FUND

These are the fees and expenses you may pay when youbuy and hold shares.

SHAREHOLDER FEES (paid directly from your investment)

Account Maintenance Fee (annually, for fund account balancesbelow $10,000 and subject to certain exceptions) $20

ANNUAL FUND OPERATING EXPENSES(expenses that you pay each year as a % of the value of your investment)

Management fee 0.05

Distribution/service (12b-1) fees None

Other expenses 0.30

Total annual fund operating expenses 0.35

EXAMPLEThis Example is intended to help you compare the cost ofinvesting in the fund with the cost of investing in othermutual funds. The Example assumes that you invest$10,000 in the fund for the time periods indicated and thenredeem all of your shares at the end of those periods. TheExample also assumes that your investment has a 5%return each year and that the fund’s operating expensesremain the same. Although your actual costs may behigher or lower, based on these assumptions your costswould be:

1Year 3Years 5Years 10Years

$36 $113 $197 $443

PRINCIPAL INVESTMENT STRATEGY

Main investments. The fund is a money market fund thatis managed in accordance with federal regulations whichgovern the quality, maturity, diversity and liquidity of instru-ments in which a money market fund may invest.

The fund operates as a “government money market fund,”as such term is defined under federal regulations. As agovernment money market fund, the fund is required toinvest 99.5% or more of its total assets at the time ofinvestment in cash, short-term US Treasury securities,and/or repurchase agreements that are collateralized bythese securities.

The fund follows policies designed to maintain a stable$1.00 share price.

The fund pursues its objective by investing exclusively inshort-term US Treasury securities and in repurchase agree-ments backed by these securities. In a repurchaseagreement, the fund buys securities at one price with asimultaneous agreement to sell back the securities at afuture date at an agreed upon price. The timely payment ofprincipal and interest on US Treasury securities is guaran-teed by the full faith and credit of the US government.

The fund may invest in floating and variable rate instru-ments (obligations that do not bear interest at an agreedupon price).

Management process. Working in consultation with port-folio management, a credit team screens potentialsecurities and develops a list of those that the fund maybuy. Portfolio management, looking for attractive yield andweighing considerations such as credit quality, economicoutlooks and possible interest rate movements, thendecides which securities on this list to buy.

MAIN RISKS

There are several risk factors that could reduce the yieldyou get from the fund, cause the fund’s performance totrail that of other investments, or cause you to lose money.

1Prospectus August 1, 2018 DWS Treasury Portfolio

Money market fund risk. You could lose money byinvesting in the fund. Although the fund seeks to preservethe value of your investment at $1.00 per share, it cannotguarantee it will do so. An investment in the fund is notinsured or guaranteed by the Federal Deposit InsuranceCorporation or any other government agency. The Advisorhas no legal obligation to provide financial support to thefund, and you should not expect that the Advisor willprovide financial support to the fund at any time.

Interest rate risk. Rising interest rates could cause thevalue of the fund’s investments — and therefore its shareprice as well — to decline. Conversely, any decline ininterest rates is likely to cause the fund’s yield to decline,and during periods of unusually low interest rates, thefund’s yield may approach zero. A low interest rate envi-ronment may prevent the fund from providing a positiveyield or paying fund expenses out of current income and,at times, could impair the fund’s ability to maintain a stable$1.00 share price. Over time, the total return of a moneymarket fund may not keep pace with inflation, which couldresult in a net loss of purchasing power for long-term inves-tors. Recent and potential future changes in monetarypolicy made by central banks and/or their governments arelikely to affect the level of interest rates. Money marketfunds try to minimize this risk by purchasing short-termsecurities.

If there is an insufficient supply of US government securi-ties to meet investor demand, it could result in lower yieldson such securities and increase interest rate risk for thefund.

Security selection risk. Although short-term securitiesare relatively stable investments, it is possible that thesecurities in which the fund invests will not perform asexpected. This could cause the fund’s returns to lag behindthose of similar money market funds and could result in adecline in share price.

Repurchase agreement risk. If the party that sells thesecurities to the fund defaults on its obligation to repur-chase them at the agreed-upon time and price, the fundcould lose money.

Counterparty risk. A financial institution or othercounterparty with whom the fund does business, or thatunderwrites, distributes or guarantees any investments orcontracts that the fund owns or is otherwise exposed to,may decline in financial health and become unable tohonor its commitments. This could cause losses for thefund or could delay the return or delivery of collateral orother assets to the fund.

Credit risk. The fund’s performance could be hurt and thefund’s share price could fall below $1.00 if an issuer of adebt security suffers an adverse change in financial condi-tion that results in the issuer not making timely paymentsof interest or principal, a security downgrade or an inabilityto meet a financial obligation.

Because of the rising US government debt burden, it ispossible that the US government may not be able to meetits financial obligations or that securities issued by theUS government may experience credit downgrades. Sucha credit event may also adversely impact the financialmarkets and the fund.

Liquidity and transaction risk. The liquidity of portfoliosecurities can deteriorate rapidly due to credit eventsaffecting issuers or due to general market conditions and alack of willing buyers. When there are no willing buyersand an instrument cannot be readily sold at a desired timeor price, the fund may have to accept a lower price or maynot be able to sell the instrument at all. If dealer capacityin debt instruments is insufficient for market conditions, itmay further inhibit liquidity and increase volatility in thedebt markets. Additionally, market participants other thanthe fund may attempt to sell debt holdings at the sametime as the fund, which could cause downward pricingpressure and contribute to illiquidity. An inability to sell oneor more portfolio securities can adversely affect the fund’sability to maintain a $1.00 share price or prevent the fundfrom being able to take advantage of other investmentopportunities.

Unusual market conditions, an unusually high volume ofredemption requests or other similar conditions couldcause the fund to be unable to pay redemption proceedswithin a short period of time. If the fund is forced to sellsecurities at an unfavorable time and/or under unfavorableconditions, such sales may adversely affect the fund’sability to maintain a $1.00 share price.

Risks of holding cash. The fund will at times hold cashpositions, which may hurt the fund’s performance. Cashpositions may also subject the fund to additional risks andcosts, including any fees imposed by the fund’s custo-dian for large cash balances.

Market risk. The market value of the securities in whichthe fund invests may be impacted by the prospects of indi-vidual issuers, particular sectors or governments and/orgeneral economic conditions throughout the world due toincreasingly interconnected global economies and financialmarkets.

Operational and technology risk. Cyber-attacks, disrup-tions, or failures that affect the fund’s service providers orcounterparties, issuers of securities held by the fund, orother market participants may adversely affect the fundand its shareholders, including by causing losses for thefund or impairing fund operations.

PAST PERFORMANCE

How a fund’s returns vary from year to year can give anidea of its risk. Past performance may not indicate futureresults. All performance figures below assume that divi-dends were reinvested. The 7-day yield, which is oftenreferred to as the “current yield,” is the income generatedby the fund over a seven-day period. This amount is then


annualized, which means that we assume the fund gener-ates the same income every week for a year. For morerecent performance figures and the current yield, go todws.com (the Web site does not form a part of thisprospectus) or call the telephone number included in thisprospectus.

CALENDAR YEAR TOTAL RETURNS (%) (DWS U.S. Trea-

sury Money Fund Class S)

Returns for other classes were different and are not shownhere.

1.58

0.07 0.01 0.01 0.01 0.01 0.01 0.010.13

0.71

0

0.5

1.0

1.5

2.0

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Returns Period ending

Best Quarter 0.61% March 31, 2008Worst Quarter 0.00% March 31, 2010Year-to-Date 0.70% June 30, 2018

AVERAGE ANNUAL TOTAL RETURNS(For periods ended 12/31/2017 expressed as a %) (DWS U.S. Treasury

Money Fund Class S)

ClassInception

1Year

5Years

10Years

5/18/2007 0.71 0.17 0.25

Total returns would have been lower if operating expenseshad not been reduced.

For more recent performance information, contact thefinancial services firm from which you obtained thisprospectus.

MANAGEMENT

Investment Advisor

DWS Investment Management Americas, Inc.

PURCHASE AND SALE OF FUND SHARES

MINIMUM INITIAL INVESTMENT ($)

Non-IRA IRAsUGMAs/

UTMAs

AutomaticInvestment

Plans

S 2,500 1,000 1,000 1,000

For participants in all group retirement plans, and in certain fee-based andwrap programs approved by the Advisor, there is no minimum initial invest-ment and no minimum additional investment for Class S shares. ForSection 529 college savings plans, there is no minimum initial investmentand no minimum additional investment for Class S shares. The minimumadditional investment in all other instances is $50.

TO PLACE ORDERS

Mail New Accounts DWSPO Box 219356Kansas City, MO 64121-9356

Additional Investments DWSPO Box 219154Kansas City, MO 64121-9154

Exchanges andRedemptions

DWSPO Box 219557Kansas City, MO 64121-9557

Expedited Mail DWS210 West 10th StreetKansas City, MO 64105-1614

Web Site dws.com

Telephone (800) 728-3337, M – F 8 a.m. – 7 p.m. ET

TDD Line (800) 972-3006, M – F 8 a.m. – 7 p.m. ET

The fund is generally open on days when the New YorkStock Exchange is open for regular trading. Initial invest-ments must be sent by mail. You can make additionalinvestments or sell shares of the fund on any business dayby visiting our Web site, by mail, or by telephone; howeveryou may have to elect certain privileges on your initialaccount application. If you are working with a financialadvisor, contact your financial advisor for assistance withbuying or selling fund shares.

TAX INFORMATION

The fund’s distributions are generally taxable to you asordinary income or capital gains, except when your invest-ment is in an IRA, 401(k), or other tax-advantagedinvestment plan. Any withdrawals you make from suchtax-advantaged investment plans, however, may be taxableto you.

PAYMENTS TO BROKER-DEALERS AND

OTHER FINANCIAL INTERMEDIARIES

If you purchase the fund through a broker-dealer or otherfinancial intermediary (such as a bank), the fund, theAdvisor, and/or the Advisor’s affiliates may pay the inter-mediary for the sale of fund shares and related services.These payments may create a conflict of interest by influ-encing the broker-dealer or other intermediary and yoursalesperson to recommend the fund over another invest-ment. Ask your salesperson or visit your financialintermediary’s Web site for more information.


Fund Details

ADDITIONAL INFORMATION ABOUT FUND

STRATEGIES AND RISKS

INVESTMENT OBJECTIVE

The fund seeks to provide maximum current incomeconsistent with stability of capital.

PRINCIPAL INVESTMENT STRATEGY

Main investments. The fund is a money market fund thatis managed in accordance with federal regulations whichgovern the quality, maturity, diversity and liquidity of instru-ments in which a money market fund may invest. The fundfollows policies designed to seek to maintain a stable$1.00 share price:� Fund securities are denominated in US dollars and, at

the time of purchase, have remaining maturities of 397days (about 13 months) or less, or have certain maturityshortening features (such as interest rate resets anddemand features) that have the effect of reducing theirmaturities to 397 days or less.

� The fund maintains a dollar-weighted average maturityof (i) 60 days or less and (ii) 120 days or less determinedwithout regard to interest rate resets.

� The fund maintains certain minimum liquidity standardssuch that:- the fund may not purchase a security other than a

security offering daily liquidity if, immediately afterpurchase, the fund would have invested less than 10%of its total assets in securities offering daily liquidity(includes securities that mature or are subject todemand within one business day, cash or direct USgovernment obligations);

- the fund may not purchase a security other than asecurity offering weekly liquidity if, immediately afterpurchase, the fund would have invested less than 30%of its total assets in securities offering weekly liquidity(includes securities that mature or are subject todemand within five business days, cash and direct USgovernment obligations); and

- the fund may not purchase an illiquid security if, imme-diately after purchase, the fund would have investedmore than 5% of its total assets in illiquid securities(securities that cannot be sold or disposed of in theordinary course of business within seven days atapproximately the market value ascribed to them bythe fund).

The fund operates as a “government money market fund,”as such term is defined under federal regulations. As agovernment money market fund, the fund is required toinvest 99.5% or more of its total assets at the time ofinvestment in cash, short-term US Treasury securities,and/or repurchase agreements that are collateralized bythese securities.

The fund pursues its objective by investing exclusively inshort-term US Treasury securities and in repurchase agree-ments backed by these securities. In a repurchaseagreement, the fund buys securities at one price with asimultaneous agreement to sell back the securities at afuture date at an agreed upon price. The timely payment ofprincipal and interest on US Treasury securities is guaran-teed by the full faith and credit of the US government.

The fund may invest in floating and variable rate instru-ments (obligations that do not bear interest at an agreedupon price).

Management process. Working in consultation with port-folio management, a credit team screens potentialsecurities and develops a list of those that the fund maybuy. Portfolio management, looking for attractive yield andweighing considerations such as credit quality, economicoutlooks and possible interest rate movements, thendecides which securities on this list to buy.

Portfolio management may adjust the fund’s exposure tointerest rate risk, typically seeking to take advantage ofpossible rises in interest rates and to preserve yield wheninterest rates appear likely to fall.

MAIN RISKS

There are several risk factors that could reduce the yieldyou get from the fund, cause the fund’s performance totrail that of other investments, or cause you to lose money.

4Prospectus August 1, 2018 Fund Details

Money market fund risk. You could lose money byinvesting in the fund. Although the fund seeks to preservethe value of your investment at $1.00 per share, it cannotguarantee it will do so. An investment in the fund is notinsured or guaranteed by the Federal Deposit InsuranceCorporation or any other government agency. The Advisorhas no legal obligation to provide financial support to thefund, and you should not expect that the Advisor willprovide financial support to the fund at any time.

Interest rate risk. Rising interest rates could cause thevalue of the fund’s investments — and therefore its shareprice as well — to decline. Conversely, any decline ininterest rates is likely to cause the fund’s yield to decline,and during periods of unusually low interest rates, thefund’s yield may approach zero. A low interest rate envi-ronment may prevent the fund from providing a positiveyield or paying fund expenses out of current income and,at times, could impair the fund’s ability to maintain a stable$1.00 share price. Over time, the total return of a moneymarket fund may not keep pace with inflation, which couldresult in a net loss of purchasing power for long-term inves-tors. Recent and potential future changes in monetarypolicy made by central banks and/or their governments arelikely to affect the level of interest rates. Money marketfunds try to minimize this risk by purchasing short-termsecurities.

If there is an insufficient supply of US government securi-ties to meet investor demand, it could result in lower yieldson such securities and increase interest rate risk for thefund.

Security selection risk. Although short-term securitiesare relatively stable investments, it is possible that thesecurities in which the fund invests will not perform asexpected. This could cause the fund’s returns to lag behindthose of similar money market funds and could result in adecline in share price.

Repurchase agreement risk. If the party that sells thesecurities to the fund defaults on its obligation to repur-chase them at the agreed-upon time and price, the fundcould lose money.

Counterparty risk. A financial institution or othercounterparty with whom the fund does business, or thatunderwrites, distributes or guarantees any investments orcontracts that the fund owns or is otherwise exposed to,may decline in financial health and become unable tohonor its commitments. This could cause losses for thefund or could delay the return or delivery of collateral orother assets to the fund.

Credit risk. The fund’s performance could be hurt and thefund’s share price could fall below $1.00 if an issuer of adebt security suffers an adverse change in financial condi-tion that results in the issuer not making timely paymentsof interest or principal, a security downgrade or an inabilityto meet a financial obligation.

Because of the rising US government debt burden, it ispossible that the US government may not be able to meetits financial obligations or that securities issued by theUS government may experience credit downgrades. Sucha credit event may also adversely impact the financialmarkets and the fund.

Liquidity and transaction risk. The liquidity of portfoliosecurities can deteriorate rapidly due to credit eventsaffecting issuers or due to general market conditions and alack of willing buyers. When there are no willing buyersand an instrument cannot be readily sold at a desired timeor price, the fund may have to accept a lower price or maynot be able to sell the instrument at all. If dealer capacityin debt instruments is insufficient for market conditions, itmay further inhibit liquidity and increase volatility in thedebt markets. Additionally, market participants other thanthe fund may attempt to sell debt holdings at the sametime as the fund, which could cause downward pricingpressure and contribute to illiquidity. An inability to sell oneor more portfolio securities can adversely affect the fund’sability to maintain a $1.00 share price or prevent the fundfrom being able to take advantage of other investmentopportunities.

Unusual market conditions, an unusually high volume ofredemption requests or other similar conditions couldcause the fund to be unable to pay redemption proceedswithin a short period of time. If the fund is forced to sellsecurities at an unfavorable time and/or under unfavorableconditions, such sales may adversely affect the fund’sability to maintain a $1.00 share price.

Certain shareholders, including clients or affiliates of theAdvisor, may from time to time own or control a significantpercentage of the fund’s shares. These shareholders mayinclude, for example, institutional investors and other share-holders whose buy-sell decisions are controlled by a singledecision maker. Redemptions by these shareholders, ora high volume of redemption requests generally, mayfurther increase the fund’s liquidity risk and may impactthe fund’s ability to maintain a $1.00 share price.

Risks of holding cash. The fund will at times hold cashpositions, which may hurt the fund’s performance. Cashpositions may also subject the fund to additional risks andcosts, including any fees imposed by the fund’s custo-dian for large cash balances.

Market risk. The market value of the securities in whichthe fund invests may be impacted by the prospects of indi-vidual issuers, particular sectors or governments and/orgeneral economic conditions throughout the world due toincreasingly interconnected global economies and financialmarkets.

Operational and technology risk. Cyber-attacks, disrup-tions, or failures that affect the fund’s service providers orcounterparties, issuers of securities held by the fund, or


other market participants may adversely affect the fundand its shareholders, including by causing losses for thefund or impairing fund operations.

Cyber-attacks may include unauthorized attempts by thirdparties to improperly access, modify, disrupt the opera-tions of, or prevent access to the systems of the fund’sservice providers or counterparties, issuers of securitiesheld by the fund or other market participants or data withinthem. In addition, power or communications outages, actsof god, information technology equipment malfunctions,operational errors, and inaccuracies within software or dataprocessing systems may also disrupt business operationsor impact critical data. Market events also may trigger avolume of transactions that overloads current informationtechnology and communication systems and processes,impacting the ability to conduct the fund’s operations.

Cyber-attacks, disruptions, or failures may adversely affectthe fund and its shareholders or cause reputationaldamage and subject the fund to regulatory fines, litigationcosts, penalties or financial losses, reimbursement orother compensation costs, and/or additional compliancecosts. For example, the fund’s or its service providers’assets or sensitive or confidential information may bemisappropriated, data may be corrupted, and operationsmay be disrupted (e.g., cyber-attacks or operational failuresmay cause the release of private shareholder informationor confidential fund information, interfere with theprocessing of shareholder transactions, impact the abilityto calculate the fund’s net asset value, and impedetrading). In addition, cyber-attacks, disruptions, or failuresinvolving a fund counterparty could affect suchcounterparty’s ability to meet its obligations to the fund,which may result in losses to the fund and its share-holders. Similar types of operational and technology risksare also present for issuers of securities held by the fund,which could have material adverse consequences for suchissuers, and may cause the fund’s investments to losevalue. Furthermore, as a result of cyber-attacks, disrup-tions, or failures, an exchange or market may close or issuetrading halts on specific securities or the entire market,which may result in the fund being, among other things,unable to buy or sell certain securities or financial instru-ments or unable to accurately price its investments.

While the fund and its service providers may establishbusiness continuity and other plans and processes thatseek to address the possibility of and fallout from cyber-attacks, disruptions, or failures, there are inherentlimitations in such plans and systems, including that theydo not apply to third parties, such as fund counterparties,issuers of securities held by the fund, or other marketparticipants, as well as the possibility that certain riskshave not been identified or that unknown threats mayemerge in the future and there is no assurance that suchplans and processes will address the possibility of andfallout from cyber-attacks, disruptions, or failures. In addi-tion, the fund cannot directly control any cybersecurity

plans and systems put in place by its service providers,fund counterparties, issuers of securities held by the fund,or other market participants.

OTHER POLICIES

While the previous pages describe the main points of thefund’s strategy and risks, there are a few other mattersto know about:� Although major changes tend to be infrequent, the

fund’s Board could change the fund’s investment objec-tive without shareholder approval. The Board will provideshareholders with at least 60 days’ notice prior tomaking any changes to the fund’s policy of investingexclusively in short-term US Treasury securities and inrepurchase agreements backed by these securities.

� While the fund currently does not intend to impose aliquidity fee or redemption gate in connection with theimplementation of federal regulations relating to moneymarket funds that went into effect on October 14, 2016,the fund may elect to do so in the future.

� From time to time, the fund may have a concentration ofshareholder accounts holding a significant percentageof shares outstanding. Investment activities of theseshareholders could have a material impact on the fund.

� Your fund assets may be at risk of being transferred tothe appropriate state if you fail to maintain a validaddress and/or if certain activity does not occur in youraccount within the time specified by state law. Contactyour financial advisor or the transfer agent for additionalinformation.

For More Information

This prospectus doesn’t tell you about every policy or riskof investing in the fund. If you want more information onthe fund’s allowable securities and investment practicesand the characteristics and risks of each one, you maywant to request a copy of the Statement of AdditionalInformation (the back cover tells you how to do this).

Keep in mind that there is no assurance that the fund willachieve its objective.

A schedule of the fund’s portfolio holdings, including infor-mation required by applicable regulations, is posted onceeach month on dws.com (the Web site does not form apart of this prospectus). Portfolio holdings as of eachmonth-end are posted to the Web site within five businessdays of the date of the applicable portfolio holdings infor-mation. More frequent posting of portfolio holdingsinformation may be made from time to time on dws.com.The posted portfolio holdings information is available byfund and generally remains accessible for a period of notless than six months. The fund also may post on the Website, on the same or a more frequent basis, various depic-tions of portfolio characteristics such as the allocation ofthe portfolio across various security types, market sectorsand sub-sectors and maturities, liquidity and risk charac-teristics of the portfolio. The fund’s Statement of Additional


Information includes a description of the fund’s policiesand procedures with respect to the disclosure of the fund’sportfolio holdings.

WHO MANAGES AND OVERSEES THE FUND

The Investment Advisor

DWS Investment Management Americas, Inc. (“DIMA” orthe “Advisor”), with headquarters at 345 Park Avenue,New York, NY 10154, is the investment advisor for thefund. Under the oversight of the Board, the Advisor makesinvestment decisions, buys and sells securities for thefund and conducts research that leads to these purchaseand sale decisions. Deutsche Bank AG reorganized itsasset management division, Deutsche Asset Manage-ment, into a separate financial services firm, DWS GroupGmbH & Co. KGaA (“DWS Group”). DWS Group is nowa separate, publicly-listed financial services firm that is anindirect, majority-owned subsidiary of Deutsche Bank AG.The Advisor is an indirect, wholly-owned subsidiary ofDWS Group. The Advisor and its predecessors have morethan 90 years of experience managing mutual funds andprovide a full range of global investment advisory servicesto institutional and retail clients.

DWS represents the asset management activitiesconducted by DWS Group or any of its subsidiaries,including DIMA, other affiliated investment advisors andDWS Distributors, Inc. (“DDI” or the “Distributor”). DWSis a global organization that offers a wide range of investingexpertise and resources, including hundreds of portfoliomanagers and analysts and an office network that reachesthe world’s major investment centers. This well-resourcedglobal investment platform brings together a wide varietyof experience and investment insight across industries,regions, asset classes and investing styles.

Management Fee. The Advisor receives a managementfee from the fund. Below is the actual rate paid by the fundfor the most recent fiscal year, as a percentage of thefund’s average daily net assets.

Fund Name Fee Paid

DWS Treasury Portfolio 0.04%*

* Reflecting the effect of expense limitations and/or fee waivers then ineffect.

From time to time, the Advisor may voluntarily waive aportion of its fees and/or reimburse certain operatingexpenses of the fund. These voluntary waivers and/orreimbursements may be terminated at any time at theoption of the Advisor.

A discussion regarding the basis for the Board’s approvalof the fund’s investment management agreement iscontained in the most recent shareholder report for theannual period ended March 31 or semi-annual periodended September 30 (see “Shareholder reports” on theback cover).

Under a separate administrative services agreementbetween the fund and the Advisor, the fund pays theAdvisor a fee of 0.10% of the fund’s average daily netassets for providing most of the fund’s administrativeservices. The administrative services fee discussed aboveis included in the fees and expenses table under “Otherexpenses.”

Multi-Manager Structure. The Advisor, subject to theapproval of the Board, has ultimate responsibility tooversee any subadvisor to the fund and to recommend thehiring, termination and replacement of subadvisors. Thefund and the Advisor have received an order from the SECthat permits the Advisor to appoint or replace certainsubadvisors, to manage all or a portion of the fund’s assetsand enter into, amend or terminate a subadvisory agree-ment with certain subadvisors, in each case subject to theapproval of the fund’s Board but without obtaining share-holder approval (“multi-manager structure”). The multi-manager structure applies to subadvisors that are notaffiliated with the fund or the Advisor (“nonaffiliatedsubadvisors”), as well as subadvisors that are indirect ordirect, wholly-owned subsidiaries of the Advisor or that areindirect or direct, wholly-owned subsidiaries of the samecompany that, indirectly or directly, wholly owns theAdvisor (“wholly-owned subadvisors”). Pursuant to theSEC order, the Advisor, with the approval of the fund’sBoard, has the discretion to terminate any subadvisor andallocate and reallocate the fund’s assets among any othernonaffiliated subadvisors or wholly-owned subadvisors(including terminating a nonaffiliated subadvisor andreplacing it with a wholly-owned subadvisor). The fund andthe Advisor are subject to the conditions imposed by theSEC order, including the condition that within 90 days ofhiring a new subadvisor pursuant to the multi-managerstructure, the fund will provide shareholders with an infor-mation statement containing information about the newsubadvisor. The shareholders of the fund have approvedthe multi-manager structure described herein.

MANAGEMENT

A group of investment professionals is responsible for theday-to-day management of the fund. These investmentprofessionals have a broad range of experience managingmoney market funds.


Investing in the Fund

Your financial advisor may also charge you additional fees,commissions or other charges.

The following pages tell you how to invest in the fund andwhat to expect as a shareholder. The following pages alsotell you about many of the services, choices and benefitsof being a shareholder. You’ll also find information on howto check the status of your account.

If you’re investing directly with DWS, all of this informationapplies to you. If you’re investing through a “third partyprovider” — for example, a workplace retirement plan,financial supermarket or financial advisor — your providermay have its own policies or instructions and you shouldfollow those.

You can find out more about the topics covered here byspeaking with your financial advisor or a representative ofyour workplace retirement plan or other investmentprovider. For an analysis of the fees associated with aninvestment in the fund or similar funds, please refer toapps.finra.org/fundanalyzer/1/fa.aspx (this Web site doesnot form a part of this prospectus).

Class S Shares

Class S shares have no initial sales charge, deferred salescharge or 12b-1 fees.

Class S shares are principally available to new investorsthrough fee-based programs of investment dealers thathave special agreements with the fund’s distributor,through certain group retirement plans and through certainregistered investment advisors. These dealers and advi-sors typically charge ongoing fees for services theyprovide.

Eligibility Requirements. Class S shares of a fund areoffered at net asset value without a sales charge to certaineligible investors as described below. The following inves-tors may purchase Class S shares of DWS funds either(i) directly from DDI, the fund’s principal underwriter; or (ii)through an intermediary relationship with a financialservices firm established with respect to the DWS fundsas of December 31, 2004:

� Existing shareholders of Class S shares of any DWSfund and household members residing at the sameaddress may purchase Class S shares of such fund andmay open new individual accounts for Class S sharesof any DWS fund. (This provision applies to persons whoin the future become Class S shareholders under oneof the eligibility provisions in this paragraph but is notapplicable to investors or participants holding Class Sshares through the fee-based, retirement or otherprograms or plans referred to in the next paragraphunless otherwise provided below.)

� A person who certifies that they are a participant in a“DWS retirement plan” may purchase Class S sharesapart from the participant’s plan. For this purpose, aDWS retirement plan is defined as (i) an employer spon-sored employee benefit plan made available throughADP, Inc. and/or its affiliates under an alliance betweenADP, Inc. and DWS or its affiliates; or (ii) a 403(b) plan forwhich Ascensus, Inc. provides recordkeeping servicesand DWS Trust Company acts as the custodian.

� A person who certifies that they are a participant whoowns Class S shares of any DWS fund through a retire-ment, employee stock, bonus, pension or profit sharingplan may purchase Class S shares apart from the partici-pant’s plan.

� Any participant in any employer sponsored retirement,employee stock, bonus, pension or profit sharing planmay purchase Class S shares in connection with a roll-over of a distribution from a plan to a DWS IRA madethrough a rollover facilitator having a relationship withDWS.

� Any person that has an existing account with DeutscheBank Wealth Management (“Deutsche Bank WM”) butwho no longer meets the eligibility requirements tomaintain an account with Deutsche Bank WM may opena new account in Class S shares of any DWS fund.

� Class S shares are available to accounts managed by theAdvisor, any advisory products offered by the Advisoror DDI and to funds-of-funds managed by the Advisor orits affiliates.

� A person who certifies that they are a former employeeof the Advisor or one of its affiliates may purchase ClassS shares in connection with a rollover of a distributionfrom a Deutsche Bank employee benefit plan to a DWSIRA.

8Prospectus August 1, 2018 Investing in the Fund

� Fund Board Members and their family members and full-time employees of the Advisor and its affiliates and theirfamily members may purchase Class S shares.

The following additional investors may purchase Class Sshares of DWS funds in connection with certain programsor plans:� Broker-dealers, banks and registered investment advi-

sors (“RIAs”) in connection with a comprehensive or“wrap” fee program or other fee-based program.

� Any group retirement, employee stock, bonus, pensionor profit-sharing plans.

� Plans administered as college savings plans underSection 529 of the Internal Revenue Code.

� Persons who purchase shares through a Health SavingsAccount or a Voluntary Employees’ Benefit Association(“VEBA”) Trust.

DDI may, at its discretion, require appropriate documenta-tion that shows an investor is eligible to purchase ClassS shares.

BUYING, EXCHANGING AND SELLING SHARES

To contact DWS

BY PHONE(800) 728-3337

BY MAIL

Type Address

Expedited mail

All Requests DWS210 West 10th StreetKansas City, MO 64105-1614

Regular mail

New Accounts DWSP.O. Box 219356Kansas City, MO 64121-9356

AdditionalInvestments

DWSP.O. Box 219154Kansas City, MO 64121-9154

Exchanges andRedemptions

DWSP.O. Box 219557Kansas City, MO 64121-9557

HOWTO BUY SHARES

Please note that your account cannot be opened until wereceive a completed account application.

MINIMUM INITIAL INVESTMENT ($)

Non-IRA IRAsUGMAs/

UTMAs

AutomaticInvestment

Plans

S 2,500 1,000 1,000 1,000

For participants in all group retirement plans, and in certain fee-based andwrap programs approved by the Advisor, there is no minimum initial invest-ment and no minimum additional investment for Class S shares. ForSection 529 college savings plans, there is no minimum initial investmentand no minimum additional investment for Class S shares. The minimumadditional investment in all other instances is $50.

Through a Financial Advisor

Contact your financial advisor to obtain a new accountapplication or for instructions about how to set up a newaccount. Your financial advisor can also assist with makingadditional investments into an existing account.

By Mail or Expedited Mail

To establish an account, simply complete the appropriateapplication and mail it to the address provided on the form.With your application, include your check made payableto “DWS” for the required initial minimum investment.

Once your account is established, to make additional invest-ments, send a check made payable to “DWS” and aninvestment slip to the appropriate address. If you do nothave an investment slip, include a letter with your name,account number, the full fund name and share class, andyour investment instructions. If your check fails to clear,the fund has the right to cancel your order, hold you liableor charge you or your account for any losses or fees thefund or its agents have incurred.

By Automatic Investment Plan

If you wish to take advantage of the lower initial invest-ment minimums by establishing an Automatic InvestmentPlan, make sure to complete that section on the newaccount application and attach a voided check for the bankaccount from which the funds will be drawn. Subsequentinvestments are made automatically from the sharehold-er’s account at a bank, savings and loan or credit union intothe shareholder’s fund account. The maximum AutomaticInvestment Plan investment is $250,000. Termination bya shareholder will become effective within thirty days afterDWS has received the request. The fund may immedi-ately terminate a shareholder’s Automatic Investment Planin the event that any item is unpaid by the shareholder’sfinancial institution.

Other Ways to Buy Shares

The following privileges must be established on youraccount before an investment request is made. This caneither be done by completing the applicable section(s) onthe new account application or by contacting a customerservice representative for instructions.

By Phone Using QuickBuy (for additional investments

only). Call DWS and use our automated system to placeyour QuickBuy purchase using the Automated ClearingHouse system (ACH) or choose to be transferred to acustomer service representative to complete your request.Transactions take two to three days to be completed andthere is a $50 minimum and a $250,000 maximum.


On the Internet (for additional investments only).

Register at dws.com to set up on-line access to youraccount(s), or log in to the Web site if you have previouslyregistered. Follow the instructions on the Web site torequest a purchase with money from the bank accountyou have established on your DWS fund account(s).

HOWTO EXCHANGE SHARES

REQUIREMENTS AND LIMITS

Class Exchanging into Another Fund ($)

S 2,500 minimum into new non-IRA accounts perfund1,000 minimum into new IRA and UTMA/UGMAaccounts per fund50 minimum into all existing accounts per fund

Exchanges between funds are allowed between like share classes only.


In addition to what is detailed below, your financial advisorcan assist you with exchanging shares. Please contactyour financial advisor using the method that is most conve-nient for you.

By Phone

Call DWS and use our automated system to place yourexchange or choose to be transferred to a customerservice representative to complete your request. Foraccounts with $5,000 or more, you may also establish aSystematic Exchange Plan of a minimum of $50 to anotherDWS fund on a regular basis. A representative can assistyou with establishing this privilege.

On the Internet

Register at dws.com to set up on-line access to youraccount(s), or log in to the Web site if you have previouslyregistered. Follow the instructions on the Web site torequest an exchange to another DWS fund.


Write a letter that includes the following information: thename(s) of all owners and address as they appear on youraccount, the fund name, share class, and account numberfrom which you want to exchange, the dollar amount ornumber of shares you wish to exchange, and the name ofthe fund into which you want to exchange. Also includea daytime telephone number if we have any questions. Allowners should sign the letter and it should be mailed tothe appropriate address for exchanges and redemptions.

HOWTO SELL SHARES

REQUIREMENTS AND LIMITS

Class Selling Shares ($)

S Check redemption:Up to 100,000. More than 100,000 see“Signature Guarantee”QuickSell to your bank: Minimum 50, maximum250,000Wire redemption to your bank: Minimum 1,000Checkwriting:Minimum 100, maximum 5,000,000


In addition to what is detailed below, your financial advisorcan assist you with selling shares. Please contact yourfinancial advisor using the method that is most convenientfor you.

By Phone

Call DWS and use our automated system or choose to betransferred to a customer service representative tocomplete your request. You may request a check for theredemption amount sent to the address on the account.You may elect overnight delivery of your check for a $20fee ($25 for Saturday delivery), which will be paid byredeeming a portion of your shares equal to the amount ofthe fee. Overnight delivery is not available to a P.O. Box.


Write a letter that includes the following information: thename(s) of all owners and address as they appear on youraccount, the fund name, share class, and account numberfrom which you want to sell shares, the dollar amount ornumber of shares you wish to sell, and a daytime tele-phone number if we have questions. All owners shouldsign the letter and it should be mailed to the appropriateaddress. You may elect overnight delivery of your check fora $20 fee ($25 for Saturday delivery), which will be paidby redeeming a portion of your shares equal to the amountof the fee. Overnight delivery is not available to a P.O. Box.

Some redemptions can only be ordered in writing with aMedallion Signature Guarantee. For more information,please contact DWS (see phone number on the backcover).

Other Ways to Sell Shares

The following privileges must be established on youraccount before a redemption request is made. This caneither be done by completing the applicable section(s) onthe new account application when you establish youraccount or by contacting a customer service representa-tive for instructions. Depending on the method you chooseto request these redemptions, different transaction maxi-mums may apply.


By Phone Using QuickSell. Call DWS and use our auto-mated system to request a QuickSell redemption orchoose to be transferred to a customer service represen-tative (see table for applicable minimum and maximumamounts). The proceeds are sent via the AutomatedClearing House system (ACH) to your bank. Transactionsgenerally take two to three days to be completed. Foraccounts with $5,000 or more, you may also establish aSystematic Withdrawal Plan of a minimum of $50 to besent on a regular basis as you direct. The $5,000 valuedoes not apply to IRA accounts.

On the Internet. Register at dws.com to set up on-lineaccess to your account(s), or log in to the Web site if youhave previously registered. Follow the instructions on theWeb site to request a redemption from your account usingthe desired method from your available options.

By Wire. You may sell shares by wire only if your accountis authorized to do so. You will be paid for redeemedshares by wire transfer of funds to your financial advisor orbank upon receipt of a duly authorized redemptionrequest. For your protection, you may not change thedestination bank account over the phone.

By Writing a Check. You may sell shares of the fund bywriting a check drawn from your account (see table forapplicable minimum and maximum amounts). Your invest-ment will keep earning dividends until your check clears.It is not a good idea to close out your account using acheck because your account balance could changebetween the time you write the check and the time it isprocessed. You should also keep in mind that if you make apurchase by check and that check has not yet cleared yourbank account, that purchase amount will not be availablefor immediate redemption.

FINANCIAL INTERMEDIARY SUPPORT

PAYMENTS

The Advisor, the Distributor and/or their affiliates may payadditional compensation, out of their own assets and notas an additional charge to the fund, to selected affiliatedand unaffiliated brokers, dealers, participating insurancecompanies or other financial intermediaries (“financialadvisors”) in connection with the sale and/or distributionof fund shares or the retention and/or servicing of fundinvestors and fund shares (“revenue sharing”). Suchrevenue sharing payments are in addition to any distribu-tion or service fees payable under any Rule 12b-1 orservice plan of the fund, any recordkeeping/sub-transferagency/networking fees payable by the fund (generallythrough the Distributor or an affiliate) and/or the Distributoror Advisor to certain financial advisors for performing suchservices and any sales charges, commissions, non-cashcompensation arrangements expressly permitted underapplicable rules of the Financial Industry RegulatoryAuthority or other concessions described in the fee tableor elsewhere in this prospectus or the Statement of Addi-tional Information as payable to all financial advisors. For

example, the Advisor, the Distributor and/or their affiliatesmay, using their legitimate profits, compensate financialadvisors for providing the fund with “shelf space” oraccess to a third party platform or fund offering list or othermarketing programs, including, without limitation, inclu-sion of the fund on preferred or recommended sales lists,mutual fund “supermarket” platforms and other formalsales programs; granting the Distributor access to the finan-cial advisor’s sales force; granting the Distributor access tothe financial advisor’s conferences and meetings; assis-tance in training and educating the financial advisor’spersonnel; and obtaining other forms of marketing support.In addition, revenue sharing payments may consist of theDistributor’s and/or its affiliates’ payment or reimburse-ment of ticket charges that would otherwise be assessedby a financial advisor on an investor’s fund transactions.

The level of revenue sharing payments made to financialadvisors may be a fixed fee or based upon one or more ofthe following factors: gross sales, current assets and/ornumber of accounts of the fund attributable to the financialadvisor, the particular fund or fund type or other measuresas agreed to by the Advisor, the Distributor and/or theiraffiliates and the financial advisors or any combinationthereof. The amount of these payments is determined atthe discretion of the Advisor, the Distributor and/or theiraffiliates from time to time, may be substantial, and maybe different for different financial advisors based on, forexample, the nature of the services provided by the finan-cial advisor.

The Advisor, the Distributor and/or their affiliates currentlymake revenue sharing payments from their own assetsin connection with the sale and/or distribution of DWSfund shares or the retention and/or servicing of investorsto financial advisors in amounts that generally range from0.01% up to 0.52% of assets of the fund serviced andmaintained by the financial advisor, 0.05% to 0.25% ofsales of the fund attributable to the financial advisor, a flatfee of up to $143,750, or any combination thereof. Theseamounts are annual figures typically paid on a quarterlybasis and are subject to change at the discretion of theAdvisor, the Distributor and/or their affiliates. Receipt of, orthe prospect of receiving, this additional compensationmay influence your financial advisor’s recommendation ofthe fund or of any particular share class of the fund. Youshould review your financial advisor’s compensation disclo-sure and/or talk to your financial advisor to obtain moreinformation on how this compensation may have influ-enced your financial advisor’s recommendation of thefund. Additional information regarding these revenuesharing payments is included in the fund’s Statement ofAdditional Information, which is available to you on requestat no charge (see the back cover of this prospectus formore information on how to request a copy of the State-ment of Additional Information).


The Advisor, the Distributor and/or their affiliates may alsomake such revenue sharing payments to financial advi-sors under the terms discussed above in connection withthe distribution of both DWS funds and non-DWS funds byfinancial advisors to retirement plans that obtainrecordkeeping services from ADP, Inc. or to 403(b) plansthat obtain recordkeeping services from Ascensus, Inc. onthe DWS-branded retirement plan platform (the “Plat-form”). The level of revenue sharing payments is basedupon sales of both the DWS funds and the non-DWS fundsby the financial advisor on the Platform or current assetsof both the DWS funds and the non-DWS funds servicedand maintained by the financial advisor on the Platform.

It is likely that broker-dealers that execute portfolio transac-tions for the fund will include firms that also sell sharesof the DWS funds to their customers. However, theAdvisor will not consider sales of DWS fund shares as afactor in the selection of broker-dealers to execute portfoliotransactions for the DWS funds. Accordingly, the Advisorhas implemented policies and procedures reasonablydesigned to prevent its traders from considering sales ofDWS fund shares as a factor in the selection of broker-dealers to execute portfolio transactions for the fund. Inaddition, the Advisor, the Distributor and/or their affiliateswill not use fund brokerage to pay for their obligation toprovide additional compensation to financial advisors asdescribed above.

POLICIES YOU SHOULD KNOW ABOUT

Along with the information on the previous pages, the poli-cies below may affect you as a shareholder. Some of thisinformation, such as the section on distributions and taxes,applies to all investors, including those investing througha financial advisor.

If you are investing through a financial advisor or through aretirement plan, check the materials you received fromthem about how to buy and sell shares because particularfinancial advisors or other intermediaries may adopt poli-cies, procedures or limitations that are separate fromthose described in this prospectus. Please note that afinancial advisor or other intermediary may charge feesseparate from those charged by the fund and may becompensated by the fund.

Keep in mind that the information in this prospectusapplies only to the shares offered herein. Other shareclasses are described in separate prospectuses and havedifferent fees, requirements and services.

POLICIES ABOUT TRANSACTIONS

In accordance with requirements under anti-money laun-dering regulations, we may request additional informationand/or documents to verify your identity. This informationincludes, but is not limited to, your name, address, date ofbirth and other identifying documentation. If after reason-able effort we are unable to obtain this information toverify your identity, in accordance with federal regulations,

within the time frames established by the fund, we willprovide you with written notification and we may rejectyour application and order.

The fund will not invest your purchase until all required andrequested identification information has been providedand your application has been submitted in “good order.”The specific requirements for good order depend on thetype of account and transaction and the method ofpurchase. Contact the transfer agent if you have any ques-tions. After we receive all the information, your applicationis deemed to be in good order and we accept yourpurchase, you will receive the share price next calculated.

In the exercise of its sole discretion, the fund at any timemay, without prior notice, refuse, cancel, limit or rescindany purchase; cancel or rescind any purchase order placedthrough a financial intermediary no later than the busi-ness day after the order is received by the financialintermediary; freeze account activity; and/or involuntarilyredeem and close an existing account. Specifically, thefund reserves the right to involuntarily redeem an account(i) in case of actual or suspected fraudulent, illegal or suspi-cious activity by the account owner or any other individualassociated with the account; or (ii) if the account ownerfails to provide legally required information, including infor-mation and/or documentation related to identityverification, to the fund. The fund is not required to providejustification to a potential or existing shareholder for takingany such action. Please be advised that if the fund invol-untarily redeems and closes your account, under tax laws,you may be required to recognize a gain or a loss or other-wise incur tax consequences.

With certain limited exceptions, only US residents mayinvest in the fund.

Because orders placed through a financial advisor must beforwarded to the transfer agent, you’ll need to allow extratime for your order to be processed. Your financial advisorshould be able to tell you approximately when your orderwill be processed. It is the responsibility of your financialadvisor to forward your order to the transfer agent in atimely manner.

Transaction Processing. Orders for the purchase ofshares by wire transfer will normally be effective at theshare price next computed after receipt of the wiretransfer of the amount to be invested. If a wire transferpurchase order is received in good order before 5:00 p.m.Eastern time, it will normally receive the dividend for thatday.

Investments by check will be effective on the business dayfollowing receipt and will earn dividends the following busi-ness day.

Please contact your financial advisor for wire instructionsand purchase orders.

Orders processed through dealers or other financialservices firms via Fund/SERV will be effected at the shareprice calculated on the trade day (normally the date the


order is received). Purchases processed via Fund/SERVwill begin earning dividends on the day a fund receives thepayment (typically the next business day). For redemp-tions processed via Fund/SERV, you generally will receivedividends accrued up to, but not including, the businessday that payment for your shares is made.

When selling shares, shareholders generally receive divi-dends up to, but not including, the business day followingthe day on which the shares were sold. To sell shares,you must state whether you would like to receive theproceeds by wire or check.

In order to receive proceeds by wire, contact the transferagent before 5:00 p.m. Eastern time. After you inform thetransfer agent of the amount of your redemption, you willreceive a trade confirmation number. If the fund receives asell request before 5:00 p.m. Eastern time and the requestcalls for proceeds to be sent out by wire, the proceeds willnormally be wired on the same day. However, the sharessold will not earn that day’s dividend.

As noted below, proceeds of a redemption may bedelayed. The ability to receive “same day” wire redemp-tion proceeds can be affected by a variety ofcircumstances including the time that the request is made,the level of redemption requests and purchase orders andgeneral market conditions. A request for a same day wireredemption that is received earlier in the day will be givenpriority over a request received later in the day in the eventthat it is necessary to limit the amount of same day wireredemptions.

Sub-Minimum Balances for Class S. The fund may closeyour account and send you the proceeds if your balancefalls below $2,500 ($1,000 with an Automatic InvestmentPlan funded with $50 or more per month in subsequentinvestments); or below $250 for retirement accounts. Wewill give you 60 days’ notice (90 days for retirementaccounts) so you can either increase your balance or closeyour account (these policies don’t apply to investors with$100,000 or more in DWS fund shares, investors in certainfee-based and wrap programs offered through certain finan-cial intermediaries approved by the Advisor, or groupretirement plans and certain other accounts having lowerminimum share balance requirements).

Account Maintenance Fee. The fund charges a $20account maintenance fee for each fund account that has abalance below $10,000. Except as otherwise noted below,fund accounts are not aggregated by share class or fund.The assessment will occur once per calendar year and maybe assessed through the automatic redemption of fundshares in your account. The fee will be assessed on eachfund account that falls below the minimum for any reason,including market value fluctuations, redemptions orexchanges.

The account maintenance fee will not apply to: (i) accountswith an automatic investment plan; (ii) accounts held inan omnibus account through a financial services firm; (iii)

accounts maintained on behalf of participants in certainfee-based and wrap programs offered through certain finan-cial intermediaries approved by the Advisor; (iv) participantlevel accounts in group retirement plans held on therecords of a retirement plan record keeper; (v) accountsheld by shareholders who maintain $50,000 or more inaggregate assets in DWS fund shares; (vi) shareholderswho consent to electronic delivery for all documents(which include statements, prospectuses, annual andsemi-annual reports, and other materials), except for taxforms; (vii) Uniform Gift to Minors (UGMA) and UniformTransfer to Minors (UTMA) accounts; (viii) Coverdell Educa-tion Savings Account (ESA) accounts; and (ix) IRAaccounts for shareholders beginning in the year in whichthey turn age 70 1/2. You may elect to receive electronicdelivery of DWS fund materials by registering on dws.comor by calling the telephone number on the back cover.

Checkwriting enables you to sell shares of the fund bywriting a check. Your investment keeps earning dividendsuntil your check clears. Please note that we will not acceptchecks for less than $100. Please note that you shouldnot write checks for more than $5,000,000. Note as wellthat we can’t honor any check larger than your balanceat the time the check is presented to us. It is not a goodidea to close out an account using a check because theaccount balance could change between the time you writethe check and the time it is processed. Please keep inmind that if you make a purchase by check and that checkhas not yet cleared, those funds will not be available forimmediate redemption.

Overnight delivery of DWS fund materials. You mayrequest to receive a paper copy of any DWS fund mate-rials via overnight delivery by calling the telephone numberon the back cover. If you request an overnight deliveryyou will be charged a $20 fee ($25 for Saturday delivery)for each request, which will be paid by redeeming a portionof your shares equal to the amount of the fee. Overnightdelivery is not available to a P.O. Box.

The automated information line is available 24 hours aday by calling DWS at the phone number on the backcover. You can use our automated phone service to getinformation on DWS funds generally and on accounts helddirectly at DWS. You can also use this service to requestshare transactions.

Telephone and electronic transactions. Generally, youare automatically entitled to telephone redemption andexchange privileges, but you may elect not to have themwhen you open your account or by calling the appropriatephone number on the back cover.

Since many transactions may be initiated by telephone orelectronically, it’s important to understand that as longas we take reasonable steps to ensure that an order topurchase or redeem shares is genuine, such as recordingcalls or requesting personal security information, we arenot responsible for any losses that may occur as a result.


For transactions conducted over the Internet, we recom-mend the use of a secure Internet browser. In addition,you should verify the accuracy of your confirmation state-ments immediately after you receive them.

The fund accepts Automated Clearing House (“ACH”)

debit entries for accounts that have elected thecheckwriting redemption privilege. Upon receipt of an ACHdebit entry referencing your account number you autho-rize us to redeem shares in your account to pay the entryto the third party originating the debit. Your fund accountstatement will show all ACH debit entries in your account.In case of errors or questions about your transactions

or pre-authorized transfers please contact your financialadvisor as soon as possible if you believe your statementreflects an improper charge or if you need more informa-tion about an ACH debit entry transaction. Your financialadvisor must contact the Shareholder Service Agent withinsixty (60) days of the fund sending you the first fundaccount statement on which an improper charge appears.

The fund does not issue share certificates.

When you ask us to send or receive a wire, please notethat while we don’t charge a fee to send or receive wires,it’s possible that your bank may do so. Wire transactionsare generally completed within 24 hours. The fund can onlysend wires of $1,000 or more and accept wires of $50 ormore.

The fund accepts payment for shares only in US

dollars by a check drawn on a US bank, a bank or FederalFunds wire transfer or an electronic bank transfer. The funddoes not accept third party checks. A third party check isa check made payable to one or more parties and offeredas payment to one or more other parties (e.g., a checkmade payable to you that you offer as payment tosomeone else). Checks should be payable to DWS anddrawn by you or a financial institution on your behalf withyour name or account number included with the check.If you pay for shares by check and the check fails to clear,we have the right to cancel your order, hold you liable orcharge you or your account for any losses or fees the fundor its agents have incurred.

Signature Guarantee. When you want to sell more than$100,000 worth of shares or send proceeds to a third partyor to a new address, you’ll usually need to place yourorder in writing and have your signature guaranteed.However, if you want money transferred electronically to abank account that is already on file with us, you don’t needa signature guarantee. Also, generally you don’t need asignature guarantee for an exchange, although we mayrequire one in certain other circumstances.

A signature guarantee is simply a certification of your signa-ture — a valuable safeguard against fraud. DWS acceptsMedallion Signature Guarantees, which can be obtainedfrom an eligible guarantor. Eligible guarantor institutionsinclude commercial banks, savings and loans, trust compa-nies, credit unions, member firms of a national stock

exchange or any member or participant of an approvedsignature guarantor program. A notarized document cannotbe accepted in lieu of a signature guarantee.

Selling shares of trust accounts and business or orga-

nization accounts may require additional documentation.Please call DWS (see phone number on the back cover) orcontact your financial advisor for more information.

Money from shares you sell is sent out within one busi-ness day of the business day that your redemption order iseffective except as discussed below. In addition, asdescribed above under “Transaction Processing,” requestsfor redemptions by wire received before the daily cut-offtime will normally result in proceeds being sent out by wireon the same day. Redemption proceeds could be delayedwhen you are selling shares you bought recently by checkor ACH (the funds will be placed under a 10 calendar dayhold to ensure good funds) or when unusual circum-stances prompt the SEC to allow further delays. Certainexpedited redemption processes (e.g., redemptionproceeds by wire) may also be delayed or unavailablewhen you are selling shares recently purchased or in theevent of a non-routine closure of the Federal Reserve wirepayment system.

Redemptions will generally be in the form of cash and thefund typically expects to satisfy redemption requests byusing available cash or by selling portfolio securities if avail-able cash is not sufficient to meet redemptions. The fundmay also utilize inter-fund lending, though such use isexpected to be rare. The fund may use any of thesemethods of satisfying redemption requests under normalor stressed market conditions.

The fund reserves the right to suspend or postponeredemptions as permitted pursuant to Section 22(e) of the1940 Act. Those circumstances are when 1) the New YorkStock Exchange is closed other than customary weekendor holiday closings; 2) the SEC determines that tradingon the New York Stock Exchange is restricted; 3) the SECdetermines that an emergency exists which makes thedisposal of securities owned by the fund or the fair deter-mination of the value of the fund’s net assets notreasonably practicable; or 4) the SEC, by order or rule,permits the suspension of the right of redemption.Redemption payments by wire may also be delayed in theevent of a non-routine closure of the Federal Reserve wirepayment system. For additional rights reserved by thefund, please see “Other Rights We Reserve.”

Short-TermTrading. Since money market funds hold short-term instruments and are intended to provide liquidity toshareholders, the Advisor does not monitor or limit short-term or excessive trading activity in the fund and,accordingly, the Board of the fund has not approved anypolicies and procedures designed to limit this activity.However, the fund reserves the right to and may reject orcancel a purchase or exchange order into the fund for any


reason, including if, in the opinion of the Advisor, thereappears to be a pattern of short-term or excessive tradingby an investor in another DWS fund.

HOW THE FUND CALCULATES SHARE PRICE

To calculate net asset value, or NAV, the fund uses thefollowing equation:

( TotalAssets

−Total

Liabilities ) ÷Total Number of

Shares Outstanding= NAV

The price at which you buy and sell shares is based on theNAV per share next calculated after the order is receivedand accepted by the transfer agent.

In valuing securities, we typically use amortized cost toaccount for any premiums or discounts above or below theface value of any securities the fund buys, and round theper share NAV to the nearest whole cent.

The fund is open for business each day the New YorkStock Exchange (the “Exchange”) is open. Normally, thefund calculates its share price once every business day at5:00 p.m. Eastern time. The close of regular trading onthe Exchange is typically 4:00 p.m. Eastern time, but some-times earlier, as in the case of scheduled half-day tradingor unscheduled suspensions of trading. In the event ofscheduled partial day trading or unscheduled suspensionsof trading on the Exchange, the calculation of share priceshall be as of the close of trading on the Exchange. In suchinstances, the latest time for receipt of wire purchase trans-actions entitled to receive same day dividend treatmentand for receipt of redemption orders for same day wiretransfer of proceeds will be the earlier of: (a) 5:00 p.m.Eastern time or (b) the early closing time of the Exchange.

The fund may, but is not required to, accept certain typesof purchase and redemption orders (not includingexchanges) on days that the Exchange is closed, or beyondan Exchange early closing time (referred to as a ”LimitedTrading Period”) if: (a) the Federal Reserve system is open,(b) the primary trading markets for the fund’s portfolioinstruments are open and (c) the Advisor believes therewill be adequate liquidity in the short-term markets. Duringany such Limited Trading Period, the fund will only acceptpurchase orders by wire and telephone redemption orderswith proceeds to be sent by wire, ACH or check and willnot accept orders by any other means. (Automated Tele-phone Line orders are not permitted.) If redemptionproceeds are requested by ACH or check, the transmissionof the ACH payment or the mailing of the check, as thecase may be, will be delayed by at least one business dayin comparison to normal trading periods. Orders submittedby other means will be processed on the next day that theExchange is open. The calculation of share price will beas set forth in the prospectus for normal trading days.Orders must be submitted by the cut-off times for receiptof wire purchases entitled to that day’s dividend and forreceipt of telephone redemption orders for same day wiretransfer, which will be the earlier of: (a) the times set forth

in the prospectus for normal trading days or (b) such earliertimes that the fund determines based on the criteriadescribed above. If redemption proceeds are requested byACH or check, orders must be received prior to the calcu-lation of share price. Please call (877) 237-1131 or visit ourWeb site at dws.com for additional information aboutwhether the fund will be open for business on a particularday. Information concerning the intention of the fund tobe open for a Limited Trading Period will be available atleast one business day prior to the applicable day that theExchange is closed or is closing early in the case of sched-uled closings and as soon as practical in the case ofunscheduled closings.

OTHER RIGHTS WE RESERVE

You should be aware that we may do any of the following:� withdraw or suspend the offering of shares at any time� withhold a portion of your distributions and redemption

proceeds if we have been notified by the InternalRevenue Service that you are subject to backup with-holding, if you fail to provide us with the correct taxpayerID number and certain certifications, including certifica-tion that you are not subject to backup withholding, or ifyou are otherwise subject to withholding

� reject a new account application if you don’t provide anyrequired or requested identifying information, or for anyother reason

� refuse, cancel, limit or rescind any purchase or exchangeorder, without prior notice; freeze any account (meaningyou will not be able to purchase fund shares in youraccount); suspend account services; and/or involuntarilyredeem your account if we think that the account isbeing used for fraudulent or illegal purposes; one ormore of these actions will be taken when, at our solediscretion, they are deemed to be in the fund’s best inter-ests or when the fund is requested or compelled to doso by governmental authority or by applicable law

� close and liquidate your account if we are unable toverify your identity, or for other reasons; if we decide toclose your account, your fund shares will be redeemedat the net asset value per share next calculated after wedetermine to close your account; you may recognize again or loss on the redemption of your fund shares andyou may incur a tax liability

� change, add or withdraw various services, fees andaccount policies (for example, we may adjust the fund’sinvestment minimums at any time). All orders topurchase shares of the fund are subject to acceptanceand are not binding until confirmed or accepted inwriting

UNDERSTANDING DISTRIBUTIONS AND

TAXES

The fund intends to distribute to its shareholders virtuallyall of its net earnings. The fund can earn money in twoways: by receiving interest, dividends or other income


from securities it holds and by selling securities for morethan it paid for them. (The fund’s earnings are separatefrom any gains or losses stemming from your ownpurchase and sale of shares.) The fund may not always paya dividend or distribution for a given period.

The fund’s income dividends are declared daily and

paid monthly to shareholders. The fund may take intoaccount capital gains and losses (other than net long-termcapital gains) in its daily dividend declarations. The fundmay make additional distributions for tax purposes, ifnecessary.

Dividends declared and payable to shareholders of recordin the last quarter of a given calendar year are treated forfederal income tax purposes as if they were received byshareholders and paid by the fund on December 31 of thatyear, if such dividends are actually paid in January of thefollowing year.

You can choose how to receive your dividends and

distributions. You can have them all automatically rein-vested in fund shares (at NAV), all deposited directly toyour bank account or all sent to you by check, by wire, haveone type reinvested and the other sent to you by checkor have them invested in a different fund. Tell us your pref-erence on your application. If you don’t indicate apreference, your dividends and distributions will all be rein-vested. You will receive any unpaid dividends uponredeeming your entire account, unless you elect to receiveunpaid dividends on the next monthly dividend paymentdate.

Dividends and distributions are treated the same forfederal income tax purposes whether you receive them incash or reinvest them in additional shares.

Because the fund seeks to maintain a stable share price,you are unlikely to have capital gains or losses when yousell fund shares.

However, there can be no assurance that the fund will beable to maintain a stable share price. If the fund is not ableto maintain a stable share price or your basis in your fundshares differs from the amount received for the shareswhen the shares are sold, the sale may result in a taxablegain or loss for federal income tax purposes. Unless youelect the simplified NAV method of accounting (discussedbelow), you will generally recognize gain or loss equal tothe difference between the amount realized on the saleand your basis in your shares that were sold. In general,any gain or loss realized upon a taxable disposition ofshares will be treated for federal income tax purposes aslong-term capital gain or loss if the shares have been heldfor more than twelve months. Otherwise, the gain or losson the taxable disposition of shares of the fund will gener-ally be treated for federal income tax purposes as short-term capital gain or loss. Corporations are taxed at thesame rates on ordinary income and capital gains.

Capital losses may be subject to limitations on their use bya shareholder. For federal income tax purposes, anexchange is treated the same as a sale.

If you elect to adopt the simplified NAV method ofaccounting, rather than computing gain or loss on everytaxable disposition of fund shares as described above, youwould recognize gain or loss based on the aggregate valueof your fund shares during the computation period. Yourgain or loss would generally equal (i) the aggregate fairmarket value of your shares in the fund at the end of thecomputation period, (ii) minus the aggregate fair marketvalue of your shares at the end of the prior computationperiod, (iii) minus your “net investment” in the fund for thecomputation period. Your net investment is the aggregatecost of fund shares purchased during the computationperiod (including reinvested dividends) minus the aggre-gate amount received in taxable redemptions of fundshares during the same period. The computation periodmay be your taxable year or a shorter period, as long as allcomputation periods contain days from only one taxableyear and every day during the taxable year falls within oneand only one computation period. Any capital gain or lossrealized under the NAV method will be a short-term capitalgain or loss. Please consult your own tax advisor to deter-mine if the NAV method is appropriate for your individualcircumstances.

For federal income tax purposes, distributions of net invest-ment income are taxable as ordinary income. The funddoes not expect to make distributions that are eligible fortaxation as long-term capital gains or as qualified dividendincome.

For most shareholders, a portion of the dividends from thefund is generally exempt from state and local incometaxes. However, a portion of the fund’s dividends may betaxable as ordinary income if it came from investmentsin taxable securities, tax-exempt market discount bonds, oras the result of short or long-term capital gains.

Your fund will send you detailed federal income tax

information early each year. These statements tell youthe amount and the federal income tax classification of anydividends or distributions you received.

A 3.8% Medicare contribution tax is imposed on the “netinvestment income” of individuals, estates and trusts tothe extent their income exceeds certain thresholdamounts. For this purpose, net investment income gener-ally includes dividends that are taxable for federal incometax purposes and net gains recognized on the sale,redemption or exchange of fund shares.

If the fund’s distributions exceed its current and accumu-lated earnings and profits, the excess will be treated forfederal income tax purposes as a return of capital to theextent of your basis in your shares and thereafter as acapital gain. A return of capital distribution reduces thebasis of your shares. As a result, even though the fund


seeks to maintain a stable share price, you may recognizea capital gain when you sell your shares if you havereceived a return of capital distribution.

Because each shareholder’s tax situation is unique, askyour tax professional about the tax consequences of yourinvestment, including any state and local taxconsequences.

The above discussion summarizes certain federal incometax consequences for shareholders who are US persons. Ifyou are a non-US person, please consult your own taxadvisor with respect to the US and foreign tax conse-quences to you of an investment in the fund. For moreinformation, see “Taxes” in the Statement of AdditionalInformation.


Financial Highlights

The financial highlights are designed to help you under-stand recent financial performance. The figures in the firstpart of the table are for a single share. The total returnfigures represent the percentage that an investor in thefund would have earned (or lost), assuming all dividends

and distributions were reinvested. This information hasbeen audited by Ernst & Young LLP, independent registeredpublic accounting firm, whose report, along with thefund’s financial statements, is included in the fund’s annualreport (see “Shareholder reports” on the back cover).

DWSTreasury Portfolio — DWS U.S.Treasury Money Fund Class S

Years Ended March 31,2018 2017 2016 2015 2014

Selected Per Share Data

Net asset value, beginning of period $ 1.00 $ 1.00 $ 1.00 $ 1.00 $ 1.00

Income (loss) from investment operations:Net investment income .009 .002 .000* .000* .000*

Net realized and unrealized gain (loss) (.000)* .000* .000* .000* (.000)*

Total from investment operations .009 .002 .000* .000* .000*

Less distributions from:Net investment income (.009) (.002) (.000)* (.000)* (.000)*

Net realized gains — (.000)* (.000)* — —

Total distributions (.009) (.002) (.000)* (.000)* (.000)*

Net asset value, end of period $ 1.00 $ 1.00 $ 1.00 $ 1.00 $ 1.00

Total Return (%)a .93 .21 .02 .01 .01

Ratios to Average Net Assets and Supplemental Data

Net assets, end of period ($ millions) 100 105 91 95 102

Ratio of expenses before expense reductions (%) .35 .31 .29 .29 .30

Ratio of expenses after expense reductions (%) .21 .21 .12 .04 .06

Ratio of net investment income (%) .92 .21 .02 .01 .01

a Total return would have been lower had certain expenses not been reduced.* Amount is less than $.0005.

18Prospectus August 1, 2018 Financial Highlights

Appendix

HYPOTHETICAL EXPENSE SUMMARY

Using the annual fund operating expense ratios presentedin the fee tables in the fund prospectus, the HypotheticalExpense Summary shows the estimated fees andexpenses, in actual dollars, that would be charged on ahypothetical investment of $10,000 in the fund held for thenext 10 years and the impact of such fees and expenseson fund returns for each year and cumulatively, assuming a5% return for each year. The historical rate of return forthe fund may be higher or lower than 5% and, for moneymarket funds, is typically less than 5%. The tables alsoassume that all dividends and distributions are reinvested.The annual fund expense ratios shown are net of anycontractual fee waivers or expense reimbursements, if

any, for the period of the contractual commitment. Also,please note that if you are investing through a third partyprovider, that provider may have fees and expenses sepa-rate from those of the fund that are not reflected here.Mutual fund fees and expenses fluctuate over time andactual expenses may be higher or lower than those shown.

The Hypothetical Expense Summary should not be usedor construed as an offer to sell, a solicitation of an offer tobuy or a recommendation or endorsement of any specificmutual fund. You should carefully review the fund’sprospectus to consider the investment objective, risks,expenses and charges of the fund prior to investing.

DWSTreasury Portfolio — DWS U.S.Treasury Money Fund Class S

MaximumSales Charge:

0.00%

Initial HypotheticalInvestment:

$10,000

Assumed Rateof Return:

5%

Year

CumulativeReturn Before

Fees &Expenses

AnnualFund

ExpenseRatios

CumulativeReturn After

Fees &Expenses

HypotheticalYear-End

Balance AfterFees &

Expenses

Annual Fees&

Expenses

1 5.00% 0.35% 4.65% $10,465.00 $ 35.81

2 10.25% 0.35% 9.52% $10,951.62 $ 37.48

3 15.76% 0.35% 14.61% $11,460.87 $ 39.22

4 21.55% 0.35% 19.94% $11,993.80 $ 41.05

5 27.63% 0.35% 25.52% $12,551.52 $ 42.95

6 34.01% 0.35% 31.35% $13,135.16 $ 44.95

7 40.71% 0.35% 37.46% $13,745.95 $ 47.04

8 47.75% 0.35% 43.85% $14,385.13 $ 49.23

9 55.13% 0.35% 50.54% $15,054.04 $ 51.52

10 62.89% 0.35% 57.54% $15,754.05 $ 53.91

Total $443.16

19Prospectus August 1, 2018 Appendix

TO GET MORE INFORMATION

Shareholder reports. Additional information about thefund’s investments is available in the fund’s annual andsemi-annual reports to shareholders. In the annual report,you will find a discussion of the market conditions andinvestment strategies that significantly affected fund perfor-mance during its last fiscal year.

Statement of Additional Information (SAI). This tells youmore about the fund’s features and policies, including addi-tional risk information. The SAI is incorporated by referenceinto this document (meaning that it’s legally part of thisprospectus).

For a free copy of any of these documents or to requestother information about the fund, contact DWS at thephone number or address listed below. SAIs and share-holder reports are also available through the DWS web siteat dws.com. These documents and other informationabout the fund are available from the EDGAR Database onthe SEC’s Internet site at sec.gov. If you like, you mayobtain copies of this information, after paying a duplicatingfee, by e-mailing a request to [email protected] or bywriting the SEC at the address listed below.

You can also review and copy these documents and otherinformation about the fund, including the fund’s SAI, atthe SEC’s Public Reference Room in Washington, D.C. Infor-mation on the operation of the SEC’s Public ReferenceRoom may be obtained by calling the SEC at (202)551-8090.

In order to reduce the amount of mail you receive and tohelp reduce expenses, we generally send a single copy ofany shareholder report and prospectus to each household.If you do not want the mailing of these documents to becombined with those for other members of your house-hold, please contact your financial advisor or call thenumber provided.

CONTACT INFORMATION

DWS PO Box 219151Kansas City, MO64121-9151dws.com

(800) 728-3337

SEC Public Reference SectionWashington, D.C. 20549-1520sec.gov

Distributor DWS Distributors, Inc.222 South Riverside PlazaChicago, IL 60606-5808(800) 621-1148

SEC File Number Investors Cash TrustDWS Treasury Portfolio811-06103

(08/01/18) DUSTMF-1

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