Semi Annual Report by Investment Company Form N CSRS

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act File Number: 811-03326

Morgan Stanley U.S. Government Money Market Trust

(Exact Name of Registrant as Specified in Charter)

1585 Broadway, New York, New York 10036

(Address of Principal Executive Offices)

John H. Gernon

1585 Broadway, New York, New York 10036

(Name and Address of Agent for Services)

(212) 762-1886

(Registrant's Telephone Number)

January 31

Date of Fiscal Year End

July 31, 2024

Date of Reporting Period

Item 1. Reports to Stockholders

(a)

TABLE OF CONTENTS

(b) Not applicable.

Item 2. Code of Ethics

Not required in this filing.

Item 3. Audit Committee Financial Expert

Not required in this filing.

Item 4. Principal Accountant Fees and Services

Not required in this filing.

Item 5. Audit Committee of Listed Registrants

Not applicable.

Item 6. Schedule of Investments

Item 7. Financial Statements and Financial Highlights for Open-End Management Investment Companies

Morgan Stanley U.S. Government Money Market Trust

Semi-Annual Financial Statements and Additional Information

July 31, 2024

Morgan Stanley U.S. Government Money Market Trust

Table of Contents (unaudited)

There is no assurance that a mutual fund will achieve its investment objective. You could lose money by investing in the Fund. Although the Fund seeks to preserve the value of your investment at $1.00 per share, it cannot guarantee it will do so. An investment in a money market fund is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The Fund's sponsor has no legal obligation to provide financial support to the Fund and you should not expect that the sponsor will provide financial support to the Fund at any time.

Morgan Stanley U.S. Government Money Market Trust

Portfolio of Investments ◼July 31, 2024 (unaudited)

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SOFR Secured Overnight Financing Rate.

(a) Date of next interest rate reset.

(b) Rate shown is the yield to maturity at July 31, 2024.

(c) Security is subject to delayed delivery.

(d) Floating or variable rate securities: The rates disclosed are as of July 31, 2024. For securities based on a published reference rate and spread, the reference rate and spread are indicated in the description in the Portfolio of Investments. Certain variable rate securities may not be based on a published reference rate and spread but are determined by the issuer or agent and are based on current market conditions. These securities do not indicate a reference rate and spread in their description in the Portfolio of Investments.

(e) Securities are available for collateral in connection with securities purchased on a forward commitment basis.

(f) The aggregate cost for federal income tax purposes approximates the aggregate cost for book purposes.

Portfolio Composition

Morgan Stanley U.S. Government Money Market Trust

Financial Statements

Statement of Assets and Liabilities July 31, 2024 (unaudited)

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Financial Statements continued

Statement of Operations For the six months ended July 31, 2024 (unaudited)

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Financial Statements continued

Statements of Changes in Net Assets

Morgan Stanley U.S. Government Money Market Trust

Notes to Financial Statements ◼July 31, 2024 (unaudited)

1. Organization and Accounting Policies

Morgan Stanley U.S. Government Money Market Trust (the "Fund") is registered under the Investment Company Act of 1940, as amended (the "Act"), as a diversified, open-end management investment company. The Fund's investment objectives are security of principal, high current income and liquidity. The Fund was organized as a Massachusetts business trust on November 18, 1981 and commenced operations on February 17, 1982.

The Fund applies investment company accounting and reporting guidance Accounting Standards Codification ("ASC") Topic 946. In the preparation of these financial statements, management has evaluated subsequent events occurring after the date of the Fund's Statement of Assets and Liabilities through the date that the financial statements were issued.

The Fund has issued two classes of shares, R Class and S Class shares. The two classes have the same fees and expenses.

The Fund operates as a "government money market fund," which allows the Fund to continue to seek a stable Net Asset Value ("NAV"). The Fund is exempt from the requirements relating to the imposition of liquidity fees and/or redemption gates.

On July 12, 2023, the Securities and Exchange Commission ("SEC") approved certain regulatory changes that impact money market funds, including the Fund. Previously, the Fund, as a government money market fund, was permitted to opt-in to a liquidity fee and redemption gate framework, whereby the Fund would have had the ability to impose a liquidity fee or redemption gate if it invested less than 30% of its total assets in weekly liquid assets ("Prior Liquidity Fee and Redemption Gate Framework"). As part of the recently approved regulatory changes, the SEC revised the Prior Liquidity Fee and Redemption Gate Framework to remove (i) the ability of a money market fund to impose a redemption gate (other than as part of a liquidation) and (ii) the tie between a fund's weekly liquid asset levels and its ability to impose a liquidity fee. Accordingly, beginning October 2, 2023, the Fund is permitted to opt-in to a revised liquidity fee framework after appropriate notice to shareholders, whereby the Fund would have the ability to impose a liquidity fee of up to 2% without regard to the Fund's level of weekly liquid assets if the Fund's Board of Trustees (or its delegate) believes such fee to be in the best interest of the Fund and its shareholders ("Current Liquidity Fee Framework"). The Fund is exempt from the Current Liquidity Fee Framework, but the Fund's Board of Trustees reserves its right to opt-in to the Current Liquidity Fee Framework in the future after providing appropriate notice to shareholders.

These regulatory changes also included, among other things, an increase in minimum daily and weekly liquidity for money market funds. These regulatory changes took effect on April 2, 2024, and such changes may affect Fund operations and return potential.

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The following is a summary of significant accounting policies:

A. Valuation of Investments - Portfolio securities are valued at amortized cost, which approximates fair value, in accordance with Rule 2a-7 under the Act. The amortized cost of an instrument is determined by valuing it at its original cost and thereafter amortizing any discount or premium from its face value at a constant rate until maturity.

B. Accounting for Investments - Security transactions are accounted for on the trade date (date the order to buy or sell is executed). Realized gains and losses on security transactions are determined by the identified cost method. Discounts are accreted and premiums are amortized over the life of the respective securities and are included in interest income. Interest income is accrued daily as earned.

C. Multiple Class Allocations - Investment income, expenses and realized and unrealized gains and losses are allocated to each class of shares based upon the relative NAV on the date such items are recognized. Shareholder services fees are charged directly to the respective class.

D. Repurchase Agreements - The Fund invests directly with institutions in repurchase agreements. The Fund's custodian receives the collateral, which is marked-to-market daily to determine that the value of the collateral does not decrease below the repurchase price plus accrued interest as earned. If such a decrease occurs, additional collateral will be requested and, when received, will be added to the account to maintain full collateralization.

The Fund may enter into repurchase agreements in which eligible securities are transferred into joint trading accounts maintained by the custodian for investment companies advised by Morgan Stanley Investment Management Inc. (the "Adviser"). The Fund will participate on a pro-rata basis with the other investment companies in its share of the securities transferred under such repurchase agreements and in its share of proceeds from any repurchase or other disposition of such securities.

Repurchase agreements are subject to Master Repurchase Agreements, which are agreements between the Fund and its counterparties that typically include provisions which provide for the net settlement of all transactions and collateral with the Fund, through a single payment, in the event of default or termination. Amounts presented on the Portfolio of Investments and Statement of Assets and Liabilities are not net settlement amounts but gross. As indicated on the Portfolio of Investments, the cash or securities to be repurchased exceeds the repurchase price to be paid under the repurchase agreement reducing the net settlement amount to zero.

E. Dividends and Distributions to Shareholders - Dividends and distributions to shareholders are recorded on the close of each business day. Dividends from net investment income, if any, are declared and paid daily. Net realized capital gains, if any, are distributed at least annually.

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F. Use of Estimates - The preparation of financial statements in accordance with generally accepted accounting principles in the United States ("GAAP") requires management to make estimates and assumptions that affect the reported amounts and disclosures. Actual results could differ from those estimates.

G. Indemnifications - The Fund enters into contracts that contain a variety of indemnification clauses. The Fund's maximum exposure under these arrangements is unknown as this would involve future claims that may be made against the Fund that have not yet occurred.

2. Fair Valuation Measurements

Financial Accounting Standards Board ("FASB") ASC 820, "Fair Value Measurement" ("ASC 820"), defines fair value as the price that would be received to sell an asset or pay to transfer a liability in an orderly transaction between market participants at the measurement date. ASC 820 establishes a three-tier hierarchy to distinguish between (1) inputs that reflect the assumptions market participants would use in valuing an asset or liability developed based on market data obtained from sources independent of the reporting entity (observable inputs); and (2) inputs that reflect the reporting entity's own assumptions about the assumptions market participants would use in valuing an asset or liability developed based on the best information available in the circumstances (unobservable inputs) and to establish classification of fair value measurements for disclosure purposes. Various inputs are used in determining the value of the Fund's investments. The inputs are summarized in the three broad levels listed below:

• Level 1 - unadjusted quoted prices in active markets for identical investments

• Level 2 - other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, credit risk, etc.)

• Level 3 - significant unobservable inputs including the Fund's own assumptions in determining the fair value of investments. Factors considered in making this determination may include, but are not limited to, information obtained by contacting the issuer, analysts, or the appropriate stock exchange (for exchange-traded securities), analysis of the issuer's financial statements or other available documents and, if necessary, available information concerning other securities in similar circumstances.

The inputs or methodology used for valuing securities are not necessarily an indication of the risk associated with investing in those securities and the determination of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to each security.

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The following is a summary of the inputs used to value the Fund's investments as of July 31, 2024:

3. Advisory/Administration Agreements

Pursuant to an Investment Advisory Agreement with the Adviser, the Fund pays the Adviser an advisory fee, accrued daily and paid monthly, by applying the annual rate of 0.15% to the average daily net assets of the Fund determined as of the close of each business day.

The Adviser also serves as the Administrator to the Fund and provides administrative services pursuant to an Administration Agreement for an annual rate, accrued daily and paid monthly, of 0.05% of the Fund's average daily net assets.

Under a Sub-Administration Agreement between the Administrator and State Street Bank and Trust Company ("State Street"), State Street provides certain administrative services to the Fund. For such services, the Administrator pays State Street a portion of the fee the Administrator receives from the Fund.

The Adviser/Administrator has agreed to assume all operating expenses of the Fund and to waive the advisory fee and administration fee, as applicable, to the extent that such expenses and fees excluding certain investment related expenses, taxes, interest and other extraordinary expenses (including litigation), on an annualized basis exceeds 0.56% of the average daily net assets of the Fund. The fee waivers and/or expense reimbursements will continue for at least one year from the date of the Fund's prospectus or until such time that the Fund's Board of Trustees (the "Trustees") acts to discontinue all or a portion of such waivers and/or reimbursements when they deem such action is appropriate.

In addition, the Adviser and Administrator have also agreed to waive all or a portion of the Fund's advisory fee and administration fee, respectively, and/or reimburse expenses, to the extent that total expenses exceed total income of the Fund on a daily basis. The Adviser and Administrator may make additional voluntary fee waivers and/or expense reimbursements. The ratios of expenses to average net assets disclosed in the Fund's Financial Highlights may be lower than the maximum expense cap of

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0.56% due to these additional fee waivers and/or expense reimbursements. The Adviser and Administrator may discontinue these voluntary fee waivers and/or expense reimbursements at any time in the future. This arrangement had no effect during the most recent reporting period.

4. Shareholder Services Plan

Pursuant to a Shareholder Services Plan (the "Plan"), the Fund may pay Morgan Stanley Distribution, Inc. (the "Distributor"), an affiliate of the Adviser/Administrator, as compensation for the provision of services to shareholders a service fee up to the rate of 0.15% on an annualized basis of the average daily net assets of the Fund for R Class and S Class shares.

Reimbursements for these expenses are made in monthly payments by the Fund to the Distributor, which will in no event exceed an amount equal to a payment at the annual rate of 0.15% of the Fund's average daily net assets during the month. Expenses incurred by the Distributor pursuant to the Plan in any fiscal year will not be reimbursed by the Fund through payments accrued in any subsequent fiscal year. For the six months ended July 31, 2024, the shareholder services fee was accrued at the annual rate of 0.10%.

The Distributor has agreed to waive all or a portion of the Fund's shareholder services fee and/or reimburse expenses, to the extent that total expenses exceed total income of the Fund on a daily basis. The Distributor may discontinue this voluntary fee waiver and/or expense reimbursements at any time in the future. This arrangement had no effect during the most recent reporting period.

5. Dividend Disbursing and Transfer/Co-Transfer Agent

The Fund's dividend disbursing and transfer agent is SS&C Global Investor & Distribution Solutions, Inc. ("SS&C GIDS"). Pursuant to a Transfer Agency Agreement, the Fund pays SS&C GIDS a fee based on the number of classes, accounts and transactions relating to the Fund.

Eaton Vance Management ("EVM"), an affiliate of Morgan Stanley, provides co-transfer agency and related services to the Fund pursuant to a Co-Transfer Agency Services Agreement. For the six months ended July 31, 2024, co-transfer agency fees and expenses incurred to EVM, included in "Transfer agency fees" in the Statement of Operations, amounted to $5,270.

6. Custodian Fees

State Street (the "Custodian") also serves as Custodian for the Fund in accordance with a Custodian Agreement. The Custodian holds cash, securities and other assets of the Fund as required by the Act. Custody fees are payable monthly based on assets held in custody, investment purchases and sales activity and account maintenance fees, plus reimbursement for certain out-of-pocket expenses.

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Notes to Financial Statements ◼July 31, 2024 (unaudited) continued

7. Transactions with Affiliates

The Fund is permitted to purchase and sell securities ("cross-trade") from and to other Morgan Stanley funds as well as other funds and client accounts for which the Adviser or an affiliate of the Adviser serves as investment adviser, pursuant to procedures approved by the Trustees in compliance with Rule 17a-7 under the Act (the "Rule"). Each cross-trade is executed at the current market price in compliance with provisions of the Rule. For the six months ended July 31, 2024, the Fund did not engage in any cross-trade transactions.

Each Trustee receives an annual retainer fee for serving as a Trustee of the Morgan Stanley Funds. The aggregate compensation paid to each Trustee is paid by the Morgan Stanley Funds, and is allocated on a pro rata basis among each of the operational funds of the Morgan Stanley Funds based on the relative net assets of each of the funds. The Fund also reimburses such Trustees for travel and other out-of-pocket expenses incurred by them in connection with attending such meetings.

The Fund has an unfunded noncontributory defined benefit pension plan covering certain independent Trustees of the Fund who will have served as independent Trustees for at least five years at the time of retirement. Benefits under this plan are based on factors which include years of service and compensation. The Trustees voted to close the plan to new participants and eliminate the future benefits growth due to increases to compensation after July 31, 2003. Aggregate pension costs for the six months ended July 31, 2024, included in "Trustees' fees and expenses" in the Statement of Operations amounted to $850. At July 31, 2024, the Fund had an accrued pension liability of $35,824, which is reflected as "Trustees' fees" in the Statement of Assets and Liabilities.

The Fund has an unfunded Deferred Compensation Plan (the "Compensation Plan"), which allows each independent Trustee to defer payment of all, or a portion, of the fees he or she receives for serving on the Board of Trustees. Each eligible Trustee generally may elect to have the deferred amounts credited with a return equal to the total return on one or more of the Morgan Stanley funds that are offered as investment options under the Compensation Plan. Appreciation/depreciation and distributions received from these investments are recorded with an offsetting increase/decrease in the deferred compensation obligation and do not affect the NAV of the Fund.

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8. Shares of Beneficial Interest

Transactions in shares of beneficial interest, at $1.00 per share, were as follows:

9. Federal Income Tax Status

It is the Fund's intention to continue to qualify as a regulated investment company and distribute all of its taxable and tax-exempt income. Accordingly, no provision for federal income taxes is required in the financial statements.

FASB ASC 740-10, "Income Taxes - Overall", sets forth a minimum threshold for financial statement recognition of the benefit of a tax position taken or expected to be taken in a tax return. Management has concluded there are no significant uncertain tax positions that would require recognition in the financial statements. If applicable, the Fund recognizes interest accrued related to unrecognized tax benefits in "Interest Expense" and penalties in "Other Expenses" in the Statement of Operations. The Fund files tax returns with the U.S. Internal Revenue Service, New York and various states. Generally, each of the tax years in the four-year period ended January 31, 2024, remains subject to examination by taxing authorities.

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Notes to Financial Statements ◼July 31, 2024 (unaudited) continued

The tax character of distributions paid may differ from the character of distributions shown for GAAP purposes due to short-term capital gains being treated as ordinary income for tax purposes. The tax character of distributions paid during fiscal years 2024 and 2023 was as follows:

The amount and character of income and gains to be distributed are determined in accordance with income tax regulations which may differ from GAAP. These book/tax differences are either considered temporary or permanent in nature.

Temporary differences are attributable to differing book and tax treatments for the timing of the recognition of gains (losses) on certain investment transactions and the timing of the deductibility of certain expenses.

The Fund had no permanent differences causing reclassifications among the components of net assets for the year ended January 31, 2024.

At January 31, 2024, the components of distributable earnings for the Fund on a tax basis were as follows:

At January 31, 2024, the Fund had available for federal income tax purposes unused short-term and long-term capital losses of $160,042 and $64, respectively, that do not have an expiration date.

To the extent that capital loss carryforwards are used to offset any future capital gains realized, no capital gains tax liability will be incurred by the Fund for gains realized and not distributed. To the extent that capital gains are offset, such gains will not be distributed to the shareholders.

10. Market Risk and Risks Relating to Certain Financial Instruments

The Fund may invest in, or receive as collateral for repurchase agreements, securities issued by Federal National Mortgage Association ("FNMA") and Federal Home Loan Mortgage Corporation ("FHLMC"). Securities issued by FNMA and FHLMC are not backed by or entitled to the full faith and

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credit of the United States and are supported by the right of the issuer to borrow from the U.S. Department of the Treasury.

The Federal Housing Finance Agency ("FHFA") serves as conservator of FNMA and FHLMC and the U.S. Department of the Treasury has agreed to provide capital as needed to ensure FNMA and FHLMC continue to provide liquidity to the housing and mortgage markets.

The Fund may enter into repurchase agreements under which the Fund sends cash and takes possession of securities with an agreement that the counterparty will repurchase such securities. In the event of default on the obligation to repurchase, the Fund has the right to liquidate the collateral and apply the proceeds in satisfaction of the obligation. In the event of default or bankruptcy by the counterparty to the agreement, realization of the collateral proceeds may be subject to certain costs and delays.

The value of an investment in the Fund is based on the values of the Fund's investments, which change due to economic and other events that affect markets generally, as well as those that affect particular regions, countries, industries, companies or governments. The risks associated with these developments may be magnified if certain social, political, economic and other conditions and events adversely interrupt the global economy and financial markets. Securities in the Fund's portfolio may underperform due to inflation (or expectations for inflation), interest rates, global demand for particular products or resources, natural disasters and extreme weather events, health emergencies (such as epidemics and pandemics), terrorism, regulatory events and governmental or quasi-governmental actions. The occurrence of global events similar to those in recent years, such as terrorist attacks around the world, natural disasters, health emergencies, social and political (including geopolitical) discord and tensions or debt crises and downgrades, among others, may result in market volatility and may have long term effects on both the U.S. and global financial markets. The occurrence of such events may be sudden and unexpected, and it is difficult to predict when similar events affecting the U.S. or global financial markets may occur, the effects that such events may have and the duration of those effects (which may last for extended periods). Any such event(s) could have a significant adverse impact on the value, liquidity and risk profile of the Fund's portfolio, as well as its ability to sell securities and/or meet redemptions. Any such event(s) or similar types of factors and developments may also adversely affect the financial performance of the Fund's investments (and, in turn, the Fund's investment results) and/or negatively impact broad segments of businesses and populations and have a significant and rapid negative impact on the performance of the Fund's investments, and exacerbate preexisting risks to the Fund.

11. Other

At July 31, 2024, the Fund had record owners of 10% or greater. Investment activities of these shareholders could have a material impact on the Fund. The aggregate percentage of such owners was 90.2%.

Morgan Stanley U.S. Government Money Market Trust

Financial Highlights

Selected ratios and per share data for a share of beneficial interest outstanding throughout each period:

(1) Amount is less than $0.001.

(2) Not annualized.

(3) Reflects prior period transfer agency fees that were reimbursed in 2023. The amount of the reimbursement was immaterial on a per share basis and the impact was less than 0.005% to the total return of R Class shares.

(4) Annualized.

(5) If the Fund had not received the reimbursement of transfer agency fees from the Adviser, the net expenses and net investment income ratios, would have been as follows for R Class shares:

(6) If the Fund had borne all of its expenses that were reimbursed or waived by the Distributor and/or Adviser/Administrator, the net expenses and net investment income (loss) ratios would have been as follows for R Class shares:

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Financial Highlights continued