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Master Trust

07/07/2025 | Press release | Distributed by Public on 07/07/2025 15:08

Annual Report by Investment Company (Form N-CSR)

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: 811-22078

Master Trust

(Exact name of registrant as specified in charter)

787 Seventh Avenue, New York, New York 10019

(Address of principal executive offices) (Zip code)

Keith A. Weller, Esq.

UBS Asset Management

One North Wacker Drive

Chicago, IL 60606

(Name and address of agent for service)

Copy to:

Stephen H. Bier, Esq.

Dechert LLP

1095 Avenue of the Americas

New York, NY 10036-6797

Registrants telephone number, including area code: 888-793-8637

Date of fiscal year end: April 30

Date of reporting period: April 30, 2025

Item 1. Reports to Stockholders.

(a)

Copy of the report transmitted to shareholders:

Fund within the Master Trust do not issue shares and therefore have no shareholders to provide with Tailored Shareholder Reports.

(b)

Copy of each notice transmitted to shareholders in reliance on Rule 30e-3 under the Investment Company Act of 1940, as amended (the 1940 Act), that contains disclosures specified by paragraph (c)(3) of that rule: Not applicable to the registrant.

Item 2. Code of Ethics.

The registrant has adopted a code of ethics that applies to its principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions pursuant to Section 406 of the Sarbanes-Oxley Act of 2002. (The registrant has designated the code of ethics adopted pursuant to Sarbanes-Oxley as a Code of Conduct to lessen the risk of confusion with its separate code of ethics adopted pursuant to Rule 17j-1 under the 1940 Act.)

Item 3. Audit Committee Financial Expert.

The registrants Board has determined that the following person serving on the registrants Audit Committee is an audit committee financial expert as defined in item 3 of Form N-CSR: Virginia G. Breen. Ms. Breen is independent as defined in item 3 of Form N-CSR.

Item 4. Principal Accountant Fees and Services.

(a)

Audit Fees:

For the fiscal years ended April 30, 2025 and April 30, 2024, the aggregate Ernst & Young LLP (E&Y) audit fees for professional services rendered to the registrant were approximately $205,083 and $290,190, respectively.

Fees included in the audit fees category are those associated with the annual audits of financial statements and services that are normally provided in connection with statutory and regulatory filings.

(b)

Audit-Related Fees:

In each of the fiscal years ended April 30, 2025 and April 30, 2024, the aggregate audit-related fees billed by E&Y for services rendered to the registrant that are reasonably related to the performance of the audits of the financial statements, but not reported as audit fees, were approximately $0 and $17,172, respectively.

Fees included in the audit-related fees category are those associated with the reading and providing of comments on the 2024 and 2023 semiannual financial statements.

There were no audit-related fees required to be approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X during the fiscal years indicated above.

(c)

Tax Fees:

In each of the fiscal years ended April 30, 2025 and April 30, 2024, the aggregate tax fees billed by E&Y for professional services rendered to the registrant were approximately $71,670 and $50,340 respectively.

Fees included in the tax fees category comprise all services performed by professional staff in the independent accountants tax division except those services related to the audits. This category comprises fees for review of tax compliance, tax return preparation and excise tax calculations.

There were no tax fees required to be approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X during the fiscal years indicated above.

(d)

All Other Fees:

In each of the fiscal years ended April 30, 2025 and April 30, 2024, there were no fees billed by E&Y for products and services, other than the services reported in Item 4(a)-(c) above, rendered to the registrant.

Fees included in the all other fees category would consist of services related to internal control reviews, strategy and other consulting, financial information systems design and implementation, consulting on other information systems, and other tax services unrelated to the registrant.

There were no all other fees required to be approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X during the fiscal years indicated above.

(e)

(1) Audit Committee Pre-Approval Policies and Procedures:

The registrants Audit Committee (audit committee) has adopted an Audit Committee Charter (Amended and Restated as of September 14, 2016), as amended (the charter). The charter contains the audit committees pre-approval policies and procedures. Reproduced below is an excerpt from the charter regarding pre-approval policies and procedures:

The [audit] Committee shall:

Pre-approve (a) all audit and permissible non-audit services¹ to be provided to the Fund and (b) all permissible non-audit services to be provided by the Funds independent auditors to UBS AM and any Covered Service Providers, if the engagement relates directly to the operations and financial reporting of the Fund. In carrying out this responsibility, the Committee shall seek periodically from UBS AM and from the independent auditors a list of such audit and permissible non-audit services that can be expected to be rendered to the Fund, UBS AM or any Covered Service Providers by the Funds independent auditors, and an estimate of the fees sought to be paid in connection with such services. The Committee has delegated its responsibility to pre-approve any such audit and permissible non-audit services not exceeding $100,000 (excluding reasonable out-of-pocket expenses) on an annual basis to the Chairperson. All such pre-approvals will

be reported to the full Committee on a quarterly basis at the Committees next regularly scheduled meeting after the pre-approval. The Committee may not delegate to management its responsibility to pre-approve services to be performed by the independent auditor. Requests or applications to provide services that require specific pre-approval by the Committee or the Chairman will be submitted by both the Funds independent auditors and the Funds Treasurer or other designated Fund officer and must include a joint statement as to whether, in their view, the request or application is consistent with Securities and Exchange Commission (SEC) rules on auditor independence. From year to year, the Committee shall report to the Board whether this system of pre-approval has been effective and efficient or whether this Charter should be amended to allow for pre-approval pursuant to such policies and procedures as the Committee shall approve, including the delegation of some or all of the Committees pre-approval responsibilities to other persons (other than UBS AM or the Funds officers).

¹ The Committee will not approve non-audit services that the Committee believes may taint the independence of the auditors. Currently, permissible non-audit services include any professional services (including tax services) that are not prohibited services as described below, provided to the Fund by the independent auditors, other than those provided to the Fund in connection with an audit or a review of the financial statements of the Fund. Permissible non-audit services may not include: (i) bookkeeping or other services related to the accounting records or financial statements of the Fund; (ii) financial information systems design and implementation; (iii) appraisal or valuation services, fairness opinions or contribution-in-kind reports; (iv) actuarial services; (v) internal audit outsourcing services; (vi) management functions or human resources; (vii) broker or dealer, investment advisor or investment banking services; (viii) legal services and expert services unrelated to the audit; and (ix) any other service the Public Company Accounting Oversight Board (PCAOB) determines, by regulation, is impermissible. Pre-approval by the Committee of any permissible non-audit services is not required so long as: (i) the aggregate amount of all such permissible non-audit services provided to the Fund, UBS AM and any service providers controlling, controlled by or under common control with UBS AM that provide ongoing services to the Fund (Covered Service Providers) constitutes not more than 5% of the total amount of revenues paid to the independent auditors (during the fiscal year in which the permissible non-audit services are provided) by (a) the Fund, (b) UBS AM and (c) any entity controlling, controlled by, or under common control with UBS AM that provides ongoing services to the Fund during the fiscal year in which the services are provided that would have to be approved by the Committee; (ii) the permissible non-audit services were not recognized by the Fund at the time of the engagement to be non-audit services; and (iii) such services are promptly brought to the attention of the Committee and approved by the Committee (or its delegate(s)) prior to the completion of the audit.

(e)

(2) Services approved pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X:

Audit-Related Fees:

There were no amounts that were approved by the audit committee pursuant to the de minimis exception for the fiscal years ended April 30, 2025 and April 30, 2024 on behalf of the registrant.

There were no amounts that were required to be approved by the audit committee pursuant to the de minimis exception for the fiscal years ended April 30, 2025 and April 30, 2024 on behalf of the registrants service providers that relate directly to the operations and financial reporting of the registrant.

Tax Fees:

There were no amounts that were approved by the audit committee pursuant to the de minimis exception for the fiscal years ended April 30, 2025 and April 30, 2024 on behalf of the registrant.

All Other Fees:

There were no amounts that were approved by the audit committee pursuant to the de minimis exception for the fiscal years ended April 30, 2025 and April 30, 2024 on behalf of the registrant.

(f)

For the fiscal year ended April 30, 2025, if greater than 50%, specify the percentage of hours spent on the audit of the registrants financial statements for the most recent fiscal year that were attributed to work performed by persons who are not full-time, permanent employees of E&Y. According to E&Y, such amount was below 50%; therefore, disclosure item not applicable for this filing.

(g)

For the fiscal years ended April 30, 2025 and April 30, 2024, the aggregate fees billed by E&Y of $2,093,936 and $2,129,104, respectively, for non-audit services rendered on behalf of the registrant (covered), its investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) and any entity controlling, controlled by, or under common control with the adviser (non-covered) that provides (or provided during the relevant fiscal period) services to the registrant for each of the last two fiscal years of the registrant is shown in the table below:


	2025	2024
Covered Services	$71,670	$67,512
Non-Covered Services	2,022,266	2,061,592

(h)

The registrants audit committee was not required to consider whether the provision of non-audit services that were rendered to the registrants investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountants independence.

(i)

Not applicable to the registrant.

(j)

Not applicable to the registrant.

Item 5. Audit Committee of Listed Registrants.

Not applicable to the registrant.

Item 6. Investments.

(a) Included in the financial statements filed under Item 7 of this form.

(b) Not applicable.

Master Trust

Annual Financial Statements | April 30, 2025

Includes:

Government Master Fund

Treasury Master Fund

100% US Treasury Master Fund

Prime CNAV Master Fund

Master Trust

Understanding a Master Funds expenses (unaudited)

(Note: The expense information provided in this section is relevant for direct investors in the Master Funds. Investors in the related feeder funds should instead focus on separate expense examples relevant to the particular feeder funds; the expense examples for the feeder funds will reflect their proportionate share of the corresponding Master Funds expenses.)

As an owner of a Master Fund, an investor such as a feeder fund incurs ongoing costs, including management fees and other Master Fund expenses. These examples are intended to help you understand a Master Fund investors ongoing costs (in dollars) of investing in a Master Fund and to compare these costs with the ongoing costs of investing in other mutual funds.

The examples below are based on an investment of $1,000 invested at the beginning of the period and held for the entire period, November 1, 2024 to April 30, 2025.

Actual expenses

The first line in the table below for each Master Fund provides information about actual account values and actual expenses. You may use the information in this line, together with the amount you invested, to estimate the expenses that you paid over a period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the result by the number in the first line under the heading entitled Expenses paid during period to estimate the expenses you paid on your account during this period.

Hypothetical example for comparison purposes

The second line in the table below for each Master Fund provides information about hypothetical account values and hypothetical expenses based on the Master Funds actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Master Funds actual return. The hypothetical account values and expenses may not be used to estimate your actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Master Fund and other funds. To do so, compare these 5% hypothetical examples with the 5% hypothetical examples that appear in the shareholder reports of other funds.

Please note that the expenses shown in the table are meant to highlight your ongoing costs. Therefore, the second line in the table for each Master Fund is useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds, if those other funds impose transactional costsfor example, exchange fees. In addition, if those transactional costs were included, your costs for those other funds would have been higher.


	Beginning account value November 1, 2024		Ending account value April 30, 2025		Expenses paid during period 11/01/24 to 04/30/25¹		Expense ratio during the period

Government Master Fund
Actual	$	1,000.00	$	1,022.00	$	0.50		0.10	%
Hypothetical (5% annual return before expenses)		1,000.00		1,024.30		0.50		0.10

Treasury Master Fund
Actual	$	1,000.00	$	1,022.00	$	0.50		0.10	%
Hypothetical (5% annual return before expenses)		1,000.00		1,024.30		0.50		0.10

100% US Treasury Master Fund
Actual	$	1,000.00	$	1,021.80	$	0.50		0.10	%
Hypothetical (5% annual return before expenses)		1,000.00		1,024.30		0.50		0.10

Prime CNAV Master Fund
Actual	$	1,000.00	$	1,022.50	$	0.50		0.10	%
Hypothetical (5% annual return before expenses)		1,000.00		1,024.30		0.50		0.10

¹	Expenses are equal to the Master Funds annualized net expense ratio, multiplied by the average account value over the period, multiplied by 181 divided by 365 (to reflect the onehalf year period).

Master Trust

Portfolio characteristics at a glanceApril 30, 2025 (unaudited)

Government Master Fund


Characteristics
Weighted average maturity¹			19 days


Portfolio composition²
U.S. Treasury obligations	47.7	%
Repurchase agreements	33.2
U.S. government agency obligations	15.2
Other assets in excess of liabilities	3.9
Total	100.0	%

You could lose money by investing in a money market fund. Although Government Master Fund seeks to preserve the value of your investment so that the shares of each related feeder fund are at $1.00 per share, Government Master Fund cannot guarantee it will do so. An investment in a money market fund is not a bank account and not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. A money market funds sponsor is not required to reimburse the fund for losses, and you should not expect that the funds sponsor will provide financial support to a money market fund at any time, including during periods of market stress.

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

¹	The Master Funds portfolio is actively managed and its weighted average maturity will differ over time.

²	Weightings represent percentages of the Master Funds net assets as of the date indicated. The Master Funds portfolio is actively managed and its composition will vary over time.

Master Trust

Portfolio characteristics at a glanceApril 30, 2025 (unaudited) (continued)

Treasury Master Fund


Characteristics
Weighted average maturity¹			13 days


Portfolio composition²
U.S. Treasury obligations	52.4	%
Repurchase agreements	45.4
Other assets in excess of liabilities	2.2
Total	100.0	%

You could lose money by investing in a money market fund. Although Treasury Master Fund seeks to preserve the value of your investment so that the shares of each related feeder fund are at $1.00 per share, Treasury Master Fund cannot guarantee it will do so. An investment in a money market fund is not a bank account and not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. A money market funds sponsor is not required to reimburse the fund for losses, and you should not expect that the funds sponsor will provide financial support to a money market fund at any time, including during periods of market stress.

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

¹	The Master Funds portfolio is actively managed and its weighted average maturity will differ over time.

²	Weightings represent percentages of the Master Funds net assets as of the date indicated. The Master Funds portfolio is actively managed and its composition will vary over time.

Master Trust

Portfolio characteristics at a glanceApril 30, 2025 (unaudited) (continued)

100% US Treasury Master Fund


Characteristics
Weighted average maturity¹			24 days


Portfolio composition²
U.S. Treasury obligations	100.5	%
Liabilities in excess of other assets	(0.5	)
Total	100.0	%

You could lose money by investing in a money market fund. Although 100% US Treasury Master Fund seeks to preserve the value of your investment so that the shares of each related feeder fund are at $1.00 per share, 100% US Treasury Master Fund cannot guarantee it will do so. An investment in a money market fund is not a bank account and not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. A money market funds sponsor is not required to reimburse the fund for losses, and you should not expect that the funds sponsor will provide financial support to a money market fund at any time, including during periods of market stress.

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

¹	The Master Funds portfolio is actively managed and its weighted average maturity will differ over time.

²	Weightings represent percentages of the Master Funds net assets as of the date indicated. The Master Funds portfolio is actively managed and its composition will vary over time.

Master Trust

Portfolio characteristics at a glanceApril 30, 2025 (unaudited) (concluded)

Prime CNAV Master Fund


Characteristics
Weighted average maturity¹			17 days


Top five issuer breakdown by country or territory of origin²
United States	51.7	%
Japan	9.6
Sweden	6.9
Australia	5.5
Singapore	4.2
Total	77.9	%


Portfolio composition²
Commercial paper	45.5	%
Repurchase agreements	37.8
Certificates of deposit	12.3
Time deposits	3.6
Other assets in excess of liabilities	0.8
Total	100.0	%

Investments in the fund are intended to be limited to feeder funds with accounts beneficially owned by natural persons. Each feeder fund reserves the right to repurchase shares in any account that are not beneficially owned by natural persons.

You could lose money by investing in a money market fund. Although Prime CNAV Master Fund seeks to preserve the value of your investment so that the shares of each related feeder fund are at $1.00 per share, Prime CNAV Master Fund cannot guarantee it will do so. Prime CNAV Master Fund may impose a fee upon sale of your shares of each related feeder fund under certain circumstances. An investment in a money market fund is not a bank account and not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. A money market funds sponsor is not required to reimburse the fund for losses, and you should not expect that the funds sponsor will provide financial support to a money market fund at any time, including during periods of market stress.

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

¹	The Master Funds portfolio is actively managed and its weighted average maturity will differ over time.

²	Weightings represent percentages of the Master Funds net assets as of the date indicated. The Master Funds portfolio is actively managed and its composition will vary over time.

Government Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
U.S. government agency obligations15.2%
Federal Farm Credit Banks Funding Corp.
3 mo. Treasury money market yield + 0.160%, 4.405%, due 05/06/25¹	$	40,000,000	$	40,000,000
1 day USD SOFR + 0.060%, 4.420%, due 05/01/25¹		80,000,000		80,000,000
1 day USD SOFR + 0.090%, 4.450%, due 05/01/25¹		28,000,000		28,000,000
1 day USD SOFR + 0.105%, 4.465%, due 05/01/25¹		69,000,000		69,000,000
1 day USD SOFR + 0.115%, 4.475%, due 05/01/25¹		95,000,000		95,000,000
1 day USD SOFR + 0.120%, 4.480%, due 05/01/25¹		133,000,000		133,034,468
1 day USD SOFR + 0.125%, 4.485%, due 05/01/25¹		64,000,000		64,000,000
1 day USD SOFR + 0.130%, 4.490%, due 05/01/25¹		68,000,000		68,000,000
1 day USD SOFR + 0.155%, 4.515%, due 05/01/25¹		156,000,000		156,000,000
1 day USD SOFR + 0.160%, 4.520%, due 05/01/25¹		208,000,000		208,000,000
Federal Home Loan Bank Discount Notes
4.015%, due 10/17/25²		105,000,000		103,020,940
4.020%, due 10/17/25²		70,000,000		68,678,983
4.030%, due 10/27/25²		116,000,000		113,675,586
4.050%, due 10/20/25²		136,000,000		133,368,400
4.060%, due 10/22/25²		133,000,000		130,390,097
4.200%, due 07/23/25²		134,000,000		132,702,433
4.200%, due 07/24/25²		133,000,000		131,696,600
4.210%, due 07/10/25²		252,000,000		249,937,100
4.210%, due 07/21/25²		99,000,000		98,062,223
Federal Home Loan Banks
1 day USD SOFR + 0.030%, 4.390%, due 05/01/25¹		153,150,000		153,109,540
1 day USD SOFR + 0.035%, 4.395%, due 05/01/25¹		133,000,000		133,000,000
1 day USD SOFR + 0.040%, 4.400%, due 05/01/25¹		245,000,000		245,000,000
1 day USD SOFR + 0.085%, 4.445%, due 05/01/25¹		69,000,000		69,000,000
1 day USD SOFR + 0.100%, 4.460%, due 05/01/25¹		379,000,000		379,000,000
1 day USD SOFR + 0.115%, 4.475%, due 05/01/25¹		171,000,000		171,000,000
1 day USD SOFR + 0.120%, 4.480%, due 05/01/25¹		64,000,000		64,000,000
1 day USD SOFR + 0.155%, 4.515%, due 05/01/25¹		86,000,000		86,000,000
1 day USD SOFR + 0.160%, 4.520%, due 05/01/25¹		142,000,000		142,000,000
1 day USD SOFR + 0.170%, 4.530%, due 05/01/25¹		102,000,000		102,000,000
Total U.S. government agency obligations (cost$3,646,676,370)				3,646,676,370


	Face amount		Value
U.S. Treasury obligations47.7%
U.S. Treasury Bills
4.313% due 05/06/25³	$	407,000,000	$	406,762,866
4.293% due 05/27/25³		245,000,000		244,253,294
4.299% due 05/01/25³		537,000,000		537,000,000
4.299% due 05/29/25³		537,000,000		535,247,888
4.308% due 05/13/25³		402,000,000		401,438,540
4.310% due 06/12/25³		244,000,000		242,795,860
4.312% due 06/24/25³		245,000,000		243,447,312
4.313% due 05/20/25³		254,000,000		253,431,604
4.318% due 05/13/25³		259,000,000		258,633,515
4.320% due 06/05/25³		252,000,000		250,961,200
4.324% due 05/27/25³		467,000,000		465,581,747
4.325% due 05/08/25³		532,000,000		531,563,464
4.325% due 05/29/25³		386,000,000		384,725,557
4.329% due 05/20/25³		470,000,000		468,955,686
4.330% due 05/15/25³		541,000,000		540,111,107
4.330% due 05/22/25³		527,000,000		525,701,165
4.333% due 05/27/25³		401,000,000		399,770,601
4.346% due 05/22/25³		263,000,000		262,345,678
4.348% due 05/15/25³		141,000,000		140,769,152
4.414% due 05/08/25³		140,000,000		139,884,033
4.450% due 05/15/25³		139,000,000		138,767,399
4.467% due 05/22/25³		287,000,000		286,278,434
4.483% due 05/01/25³		289,000,000		289,000,000
U.S. Treasury Floating Rate Notes
3 mo. Treasury money market yield + 0.098%, 4.369% due 05/01/25¹		370,000,000		369,922,834
3 mo. Treasury money market yield + 0.150%, 4.421% due 05/01/25¹		663,000,000		663,007,575
3 mo. Treasury money market yield + 0.182%, 4.453% due 05/01/25¹		516,000,000		515,822,418
3 mo. Treasury money market yield + 0.205%, 4.476% due 05/01/25¹		810,000,000		810,459,817
3 mo. Treasury money market yield + 0.245%, 4.516% due 05/01/25¹		699,000,000		699,135,735
U.S. Treasury Notes
3.875% due 01/15/26		138,000,000		137,844,887
4.250% due 01/31/26		204,000,000		204,290,427
4.625% due 03/15/26		134,000,000		134,581,547
Total U.S. Treasury obligations (cost$11,482,491,342)				11,482,491,342

Repurchase agreements33.2%
Repurchase agreement dated 03/31/22 with MUFG Securities Americas, Inc., 4.320% due 06/04/2025, collateralized by $100 U.S. Treasury Bonds, 3.000% due 08/15/52, $41,553,297 Federal Home Loan Mortgage Corp., obligations, 2.500% to 5.608% due 07/01/50 to 05/01/55 and $86,428,284 Federal National Mortgage Association obligations, 2.500% to 6.000% due 09/01/28 to 09/01/54; (value$102,000,000); proceeds: $113,512,000⁴		100,000,000		100,000,000

Government Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value

Repurchase agreements(continued)
Repurchase agreement dated 02/01/23 with J.P. Morgan Securities LLC, 4.370% due 05/07/2025, collateralized by $236,870,200 Federal National Mortgage Association obligations, 1.500% to 7.500% due 01/01/42 to 04/01/55; (value$204,000,000); proceeds: $219,883,500⁴	$	200,000,000	$	200,000,000
Repurchase agreement dated 04/30/25 with TD Securities (USA) LLC, 4.390% due 05/01/2025, collateralized by $290,561,657 Federal Home Loan Mortgage Corp., obligations, 1.500% to 6.004% due 11/15/27 to 05/25/55 and $334,970,767 Federal National Mortgage Association obligations, 2.000% to 5.554% due 04/25/26 to 10/25/56, ; (value$408,000,001); proceeds: $400,048,778		400,000,000		400,000,000
Repurchase agreement dated 03/25/25 with J.P. Morgan Securities LLC, 4.450% due 07/29/2025, collateralized by $6,850,342,271 Federal Home Loan Mortgage Corp., obligations, zero coupon to 6.439% due 03/25/29 to 02/25/55, $2,793,395,029 Federal National Mortgage Association obligations, zero coupon to 6.500% due 07/25/28 to 03/25/55 and $3,781,483,575 Government National Mortgage Association obligations, zero coupon to 6.500% due 10/20/34 to 03/16/65; (value$515,000,000); proceeds: $502,190,000⁴		500,000,000		500,000,000
Repurchase agreement dated 04/30/25 with J.P. Morgan Securities LLC., 4.380% due 05/01/2025, collateralized by $4,468,207,934 Federal National Mortgage Association obligations, 1.500% to 7.000% due 11/01/25 to 04/01/55; (value$2,040,000,000); proceeds: $2,000,243,333		2,000,000,000		2,000,000,000


	Face amount		Value

Repurchase agreements(concluded)
Repurchase agreement dated 04/30/25 with Fixed Income Clearing Corp., 4.370% due 05/01/2025, collateralized by $374,000,000 U.S. Treasury Notes, 2.000% to 5.000% due 07/31/25 to 09/30/25, $1,633,706,800 U.S. Treasury Bill, zero coupon due 08/19/25 to 09/18/25 and $2,533,874,600 U.S. Treasury Inflation Index Notes, 0.125% to 2.375% due 07/15/25 to 10/15/28; (value$4,879,680,314); proceeds: $4,784,005,807	$	4,784,000,000	$	4,784,000,000
Total repurchase agreements (cost$7,984,000,000)				7,984,000,000
Total investments (cost$23,113,167,712 which approximates cost for federal income tax purposes)96.1%				23,113,167,712

Other assets in excess of liabilities3.9%				929,586,953
Net assets100.0%			$	24,042,754,665

For a listing of defined portfolio acronyms that are used throughout the Portfolio of investments as well as the tables that follow, please refer to the Glossary of terms used in the Portfolio of investments.

Government Master Fund

Portfolio of investmentsApril 30, 2025

Fair valuation summary

The following is a summary of the fair valuations according to the inputs used as of April 30, 2025 in valuing the Master Funds investments. In the event a Master Fund holds investments for which fair value is measured using the NAV per share practical expedient (or its equivalent), a separate column will be added to the fair value hierarchy table; this is intended to permit reconciliation to the amounts presented in the Portfolio of investments:


Description	Unadjusted quoted prices in active markets for identical investments (Level 1)	Other significant observable inputs (Level 2)		Unobservable inputs (Level 3)	Total
Assets

U.S. government agency obligations	$	$	3,646,676,370	$	$	3,646,676,370
U.S. Treasury obligations			11,482,491,342			11,482,491,342
Repurchase agreements			7,984,000,000			7,984,000,000
Total	$	$	23,113,167,712	$	$	23,113,167,712

At April 30, 2025, there were no transfers in or out of Level 3.

Portfolio footnotes

Floating or variable rate securities. The rates disclosed are as of April 30, 2025. For securities based on a published reference rate and spread, the reference rate and spread are indicated within the description. Variable rate securities with a floor or ceiling feature are disclosed at the inherent rate, where applicable. Certain variable rate securities are not 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 the description.

²	Rate shown is the discount rate at the date of purchase unless otherwise noted.

³	Rate shown reflects yield at April 30, 2025.

⁴

Investment has a put feature, which allows the Master Fund to accelerate the maturity, and a variable or floating rate. The interest rate shown is the current rate as of April 30, 2025 and changes periodically. The maturity date reflects the earliest put date and the proceeds represent the receivable of the Master Fund if the put feature was exercised as of April 30, 2025.

See accompanying notes to financial statements.

Treasury Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
U.S. Treasury obligations52.4%
U.S. Treasury Bills
4.313% due 05/06/25¹	$	668,000,000	$	667,610,797
4.291% due 06/05/25¹		412,000,000		410,313,661
4.293% due 05/27/25¹		413,000,000		411,741,268
4.299% due 05/01/25¹		900,000,000		900,000,000
4.299% due 05/29/25¹		897,000,000		894,073,288
4.308% due 05/13/25¹		692,000,000		691,033,507
4.310% due 06/12/25¹		410,000,000		407,976,650
4.312% due 06/24/25¹		413,000,000		410,382,612
4.313% due 05/20/25¹		415,000,000		414,071,322
4.318% due 05/13/25¹		429,000,000		428,392,965
4.320% due 06/05/25¹		415,000,000		413,289,278
4.324% due 05/27/25¹		802,000,000		799,564,371
4.325% due 05/08/25¹		908,000,000		907,254,935
4.325% due 05/29/25¹		624,000,000		621,939,760
4.329% due 05/20/25¹		791,000,000		789,242,442
4.330% due 05/15/25¹		904,000,000		902,514,678
4.330% due 05/22/25¹		893,000,000		890,799,127
4.333% due 05/27/25¹		640,000,000		638,037,867
4.346% due 05/22/25¹		434,000,000		432,920,244
4.348% due 05/15/25¹		219,000,000		218,641,448
4.414% due 05/08/25¹		220,000,000		219,817,767
4.450% due 05/15/25¹		217,000,000		216,636,875
4.467% due 05/22/25¹		452,000,000		450,863,597
4.483% due 05/01/25¹		441,000,000		441,000,000
U.S. Treasury Floating Rate Notes
3 mo. Treasury money market yield + 0.098%, 4.369% due 05/01/25²		608,000,000		607,875,861
3 mo. Treasury money market yield + 0.150%, 4.421% due 05/01/25²		1,493,000,000		1,493,050,731
3 mo. Treasury money market yield + 0.160%, 4.431% due 05/01/25²		413,000,000		413,000,000
3 mo. Treasury money market yield + 0.182%, 4.453% due 05/01/25²		1,241,000,000		1,240,312,933
3 mo. Treasury money market yield + 0.205%, 4.476% due 05/01/25²		1,604,000,000		1,605,060,343
3 mo. Treasury money market yield + 0.245%, 4.516% due 05/01/25²		1,969,000,000		1,969,939,262
U.S. Treasury Notes
3.875% due 01/15/26		222,000,000		221,750,470
4.250% due 01/31/26		331,000,000		331,471,233
4.625% due 03/15/26		220,000,000		220,954,778
Total U.S. Treasury obligations (cost$21,681,534,070)				21,681,534,070


	Face amount		Value
Repurchase agreements45.4%
Repurchase agreement dated 04/30/25 with MUFG Securities Americas, Inc., 4.370% due 05/01/25, collateralized by $300,378,600 U.S. Treasury Notes, 0.500% to 4.625% due 08/31/26 to 02/15/33, $45,653,500 U.S. Treasury Bill, zero coupon due 07/22/25 to 07/24/25, $177,745,700 U.S. Treasury Bonds, 1.375% to 4.625% due 02/15/43 to 02/15/55, $100 U.S. Treasury Inflation Index Bonds, 0.875% due 02/15/47 and $42,412,500 U.S. Treasury Inflation Index Notes, 0.125% to 1.250% due 10/15/26 to 07/15/30; (value$510,000,013); proceeds: $500,060,694	$	500,000,000	$	500,000,000
Repurchase agreement dated 03/20/25 with Barclays Bank PLC, 4.300% due 05/07/25, collateralized by $149,497,983 U.S. Treasury Bond Strips, zero coupon due 02/15/34, $78,944,800 U.S. Treasury Bond Principal Strips, zero coupon due 02/15/44 to 11/15/54, $14,909,500 U.S. Treasury Bonds, 4.250% due 08/15/54, $373,109,600 U.S. Treasury Inflation Index Bonds, 1.000% to 1.500% due 02/15/46 to 02/15/53 and $426,321,100 U.S. Treasury Inflation Index Notes, 0.125% to 0.625% due 10/15/25 to 01/15/26; (value$1,020,000,034); proceeds: $1,004,897,222³		1,000,000,000		1,000,000,000
Repurchase agreement dated 04/30/25 with Fixed Income Clearing Corp., 4.370% due 05/01/25, collateralized by $5,182,650,300 U.S. Treasury Notes, 0.500% to 4.875% due 11/15/25 to 11/15/34, $1,191,440,400 U.S. Treasury Bill, zero coupon due 10/16/25 to 04/16/26, $11,350,168,700 U.S. Treasury Bonds, 1.125% to 4.625% due 08/15/40 to 02/15/53, $95,000,000 U.S. Treasury Inflation Index Bonds, 1.500% to 2.000% due 01/15/26 to 02/15/53 and $2,222,000,000 U.S. Treasury Inflation Index Notes, 0.125% to 2.125% due 10/15/25 to 01/15/35; (value$17,659,260,151); proceeds: $17,315,101,606		17,313,000,000		17,313,000,000
Total repurchase agreements (cost$18,813,000,000)				18,813,000,000
Total investments (cost$40,494,534,070 which approximates cost for federal income tax purposes)97.8%				40,494,534,070

Other assets in excess of liabilities2.2%				922,758,316
Net assets100.0%			$	41,417,292,386

Treasury Master Fund

Portfolio of investmentsApril 30, 2025

Fair valuation summary


Description	Unadjusted quoted prices in active markets for identical investments (Level 1)	Other significant observable inputs (Level 2)		Unobservable inputs (Level 3)	Total
Assets

U.S. Treasury obligations	$	$	21,681,534,070	$	$	21,681,534,070
Repurchase agreements			18,813,000,000			18,813,000,000
Total	$	$	40,494,534,070	$	$	40,494,534,070

At April 30, 2025, there were no transfers in or out of Level 3.

Portfolio footnotes

¹	Rate shown reflects yield at April 30, 2025.

See accompanying notes to financial statements.

100% US Treasury Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
U.S. Treasury obligations100.5%
U.S. Treasury Bills
4.255% due 05/27/25¹	$	93,000,000	$	92,720,587
4.264% due 05/27/25¹		100,000,000		99,698,732
4.264% due 06/03/25¹		400,000,000		398,465,500
4.273% due 05/20/25¹		100,000,000		99,779,186
4.273% due 05/29/25¹		116,000,000		115,622,871
4.273% due 06/03/25¹		30,000,000		29,885,090
4.274% due 05/22/25¹		100,000,000		99,755,968
4.274% due 05/29/25¹		100,000,000		99,674,850
4.276% due 05/29/25¹		100,000,000		99,674,889
4.277% due 05/29/25¹		48,000,000		47,843,200
4.278% due 05/15/25¹		89,000,000		88,854,960
4.278% due 06/03/25¹		66,000,000		65,746,783
4.279% due 06/10/25¹		100,000,000		99,533,333
4.281% due 05/22/25¹		21,000,000		20,948,697
4.282% due 05/20/25¹		65,000,000		64,856,260
4.283% due 06/03/25¹		150,000,000		149,424,287
4.313% due 05/06/25¹		240,000,000		239,858,667
4.289% due 06/03/25¹		100,000,000		99,614,450
4.290% due 05/20/25¹		39,000,000		38,913,797
4.290% due 06/05/25¹		50,000,000		49,795,291
4.291% due 06/05/25¹		107,000,000		106,562,043
4.291% due 06/05/25¹		200,000,000		199,181,097
4.293% due 05/27/25¹		107,000,000		106,673,888
4.296% due 05/08/25¹		100,000,000		99,918,217
4.296% due 05/29/25¹		61,000,000		60,800,157
4.296% due 06/03/25¹		130,000,000		129,497,891
4.298% due 06/05/25¹		100,000,000		99,589,625
4.299% due 05/01/25¹		67,000,000		67,000,000
4.299% due 05/01/25¹		58,000,000		58,000,000
4.299% due 05/27/25¹		100,000,000		99,697,172
4.299% due 05/29/25¹		201,000,000		200,344,182
4.299% due 05/29/25¹		62,000,000		61,797,611
4.299% due 06/05/25¹		200,000,000		199,179,639
4.299% due 06/12/25¹		50,000,000		49,753,909
4.300% due 05/01/25¹		100,000,000		100,000,000
4.300% due 05/29/25¹		70,000,000		69,771,551
4.302% due 05/20/25¹		330,000,000		329,265,887
4.307% due 05/13/25¹		300,000,000		299,578,000
4.308% due 05/13/25¹		150,000,000		149,790,500
4.309% due 06/24/25¹		80,000,000		79,493,360
4.310% due 05/08/25¹		335,000,000		334,724,462
4.310% due 06/12/25¹		105,000,000		104,481,825
4.311% due 05/22/25¹		85,000,000		84,791,398
4.311% due 05/27/25¹		60,000,000		59,816,917
4.312% due 06/24/25¹		107,000,000		106,321,887
4.313% due 05/20/25¹		107,000,000		106,760,558
4.315% due 05/01/25¹		300,000,000		300,000,000
4.315% due 05/15/25¹		46,000,000		45,924,729
4.318% due 05/13/25¹		111,000,000		110,842,935
4.319% due 06/03/25¹		100,000,000		99,612,113
4.320% due 05/22/25¹		100,000,000		99,754,388
4.320% due 06/05/25¹		107,000,000		106,558,922
4.323% due 05/27/25¹		45,000,000		44,863,094
4.324% due 05/27/25¹		173,000,000		172,474,609
4.325% due 05/08/25¹		37,000,000		36,969,639
4.325% due 05/15/25¹		340,000,000		339,438,717


	Face amount		Value
U.S. Treasury obligations(continued)
4.325% due 05/29/25¹	$	163,000,000	$	162,461,828
4.329% due 05/20/25¹		173,000,000		172,615,604
4.330% due 05/15/25¹		201,000,000		200,669,746
4.330% due 05/20/25¹		100,000,000		99,777,204
4.330% due 05/22/25¹		202,000,000		201,502,154
4.333% due 05/08/25¹		25,000,000		24,979,438
4.333% due 05/27/25¹		169,000,000		168,481,874
4.338% due 05/27/25¹		100,000,000		99,694,789
4.346% due 05/22/25¹		111,000,000		110,723,841
4.348% due 05/15/25¹		45,000,000		44,926,325
4.450% due 05/15/25¹		43,000,000		42,928,044
4.467% due 05/22/25¹		83,000,000		82,791,324
U.S. Treasury Floating Rate Notes
3 mo. Treasury money market yield + 0.098%, 4.369% due 05/01/25²		145,000,000		144,967,445
3 mo. Treasury money market yield + 0.150%, 4.421% due 05/01/25²		382,250,000		382,208,412
3 mo. Treasury money market yield + 0.160%, 4.431% due 05/01/25²		107,000,000		107,000,000
3 mo. Treasury money market yield + 0.182%, 4.453% due 05/01/25²		267,000,000		266,969,454
3 mo. Treasury money market yield + 0.205%, 4.476% due 05/01/25²		358,000,000		358,253,795
3 mo. Treasury money market yield + 0.245%, 4.516% due 05/01/25²		326,928,000		327,158,887
U.S. Treasury Notes
3.875% due 01/15/26		51,000,000		50,942,676
4.250% due 01/31/26		79,000,000		79,112,469
4.625% due 03/15/26		55,000,000		55,239,030
Total U.S. Treasury obligations (cost$10,003,302,659)				10,003,302,659
Total investments (cost$10,003,302,659 which approximates cost for federal income tax purposes)100.5%				10,003,302,659

Liabilities in excess of other assets(0.5)%				(51,909,089	)
Net assets100.0%				$9,951,393,570

100% US Treasury Master Fund

Portfolio of investmentsApril 30, 2025

Fair valuation summary


Description	Unadjusted quoted prices in active market for identical investments (Level 1)	Other significant observable inputs (Level 2)		Unobservable inputs (Level 3)	Total
Assets

U.S. Treasury obligations	$	$	10,003,302,659	$	$	10,003,302,659
Total	$	$	10,003,302,659	$	$	10,003,302,659

At April 30, 2025, there were no transfers in or out of Level 3.

Portfolio footnotes

¹	Rate shown reflects yield at April 30, 2025.

See accompanying notes to financial statements.

Prime CNAV Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
Certificates of deposit12.3%
Banking-non-U.S.11.0%
Bank of Nova Scotia
1 day USD SOFR + 0.300%, 4.660%, due 05/01/25¹	$	85,000,000	$	85,000,000
Commonwealth Bank of Australia
1 day USD SOFR + 0.280%, 4.620%, due 05/01/25¹		25,000,000		25,000,000
Mitsubishi UFJ Trust & Banking Corp.
4.350%, due 05/01/25		50,000,000		50,000,000
1 day USD SOFR + 0.220%, 4.580%, due 05/01/25¹		125,000,000		125,000,000
1 day USD SOFR + 0.230%, 4.590%, due 05/01/25¹		125,000,000		124,999,498
1 day USD SOFR + 0.230%, 4.590%, due 05/01/25¹		125,000,000		125,000,000
Mizuho Bank Ltd.
4.470%, due 07/16/25		65,000,000		65,000,000
4.500%, due 08/13/25		100,000,000		100,000,000
MUFG Bank Ltd.
4.460%, due 08/08/25		100,000,000		100,000,000
4.530%, due 06/12/25		125,000,000		125,000,000
National Australia Bank Ltd. 4.700%, due 05/01/25¹		125,000,000		125,000,000
Nordea Bank Abp
1 day USD SOFR + 0.280%, 4.640%, due 05/01/25¹		62,000,000		62,000,000
1 day USD SOFR + 0.370%, 4.730%, due 05/01/25¹		42,000,000		42,000,000
Oversea-Chinese Banking Corp. Ltd.
1 day USD SOFR + 0.190%, 4.550%, due 05/01/25¹		125,000,000		125,000,000
1 day USD SOFR + 0.190%, 4.550%, due 05/01/25¹		63,000,000		63,000,000
4.580%, due 06/05/25		125,000,000		125,000,000
1 day USD SOFR + 0.240%, 4.600%, due 05/01/25¹		121,000,000		121,000,000
1 day USD SOFR + 0.240%, 4.600%, due 05/01/25¹		100,000,000		99,916,667
1 day USD SOFR + 0.400%, 4.760%, due 05/01/25¹		65,000,000		65,000,000
Skandinaviska Enskilda Banken AB
1 day USD SOFR + 0.320%, 4.680%, due 05/01/25¹		92,000,000		92,000,000
Sumitomo Mitsui Banking Corp.
4.540%, due 06/11/25²		125,000,000		125,000,000
1 day USD SOFR + 0.180%, 4.540%, due 05/01/25¹		90,000,000		90,000,000
1 day USD SOFR + 0.230%, 4.590%, due 05/01/25¹		77,000,000		77,000,000
1 day USD SOFR + 0.230%, 4.590%, due 05/01/25¹		62,000,000		62,000,000
1 day USD SOFR + 0.230%, 4.590%, due 05/01/25¹		125,000,000		125,000,000
Sumitomo Mitsui Trust Bank Ltd.
1 day USD SOFR + 0.240%, 4.600%, due 05/01/25¹		128,000,000		128,000,000


	Face amount		Value
Certificates of deposit(concluded)
Banking-non-U.S.(concluded)
Svenska Handelsbanken AB
1 day USD SOFR + 0.210%, 4.570%, due 05/01/25¹	$	125,000,000	$	125,000,000
Swedbank AB
1 day USD SOFR + 0.250%, 4.610%, due 05/01/25¹		125,000,000		125,000,000
Westpac Banking Corp.
1 day USD SOFR + 0.320%, 4.680%, due 05/01/25¹		70,000,000		70,000,000

				2,771,916,165


Banking-U.S.1.3%
Cooperatieve Rabobank UA
1 day USD SOFR + 0.210%, 4.570%, due 05/01/25¹		124,000,000		124,000,000
KBC Bank NV 4.330%, due 05/07/25		195,000,000		195,000,000

				319,000,000
Total Certificates of deposit (cost$3,090,916,165)				3,090,916,165

Commercial paper45.5%
Asset-backed-miscellaneous8.8%
Albion Capital Corp. SA/Albion Capital LLC
4.390%, due 05/28/25		53,000,000		52,825,497
4.420%, due 05/20/25		13,000,000		12,969,674
Antalis SA
4.410%, due 05/05/25²		35,000,000		34,982,850
4.410%, due 05/06/25²		28,000,000		27,982,850
4.410%, due 05/13/25²		28,410,000		28,368,237
4.410%, due 05/21/25²		23,650,000		23,592,057
Barton Capital SA
4.330%, due 05/01/25²		87,000,000		87,000,000
4.340%, due 05/06/25²		25,000,000		24,984,931
4.380%, due 05/30/25²		73,000,000		72,742,432
4.400%, due 05/23/25²		12,000,000		11,967,733
4.550%, due 05/16/25²		50,000,000		49,905,208
Cabot Trail Funding LLC
4.320%, due 05/01/25²		75,000,000		75,000,000
4.420%, due 07/28/25²		67,300,000		66,572,861
Fairway Finance Co. LLC 4.330%, due 05/01/25²		50,000,000		50,000,000
Gotham Funding Corp.
4.370%, due 06/04/25²		64,000,000		63,735,858
4.375%, due 05/06/25²		77,000,000		76,953,212
Liberty Street Funding LLC
4.300%, due 07/28/25²		30,000,000		29,684,667
4.370%, due 07/09/25²		85,000,000		84,288,054
4.380%, due 07/01/25²		42,000,000		41,688,290
LMA-Americas LLC
4.370%, due 05/05/25²		51,000,000		50,975,237
4.370%, due 05/23/25²		19,000,000		18,949,259
4.370%, due 05/27/25²		64,000,000		63,798,009
Nieuw Amsterdam Receivables Corp. BV 4.340%, due 06/02/25²		24,000,000		23,907,413

Prime CNAV Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
Commercial paper(continued)
Asset-backed-miscellaneous(concluded)
Old Line Funding LLC
4.320%, due 08/27/25²	$	42,000,000	$	41,405,280
4.350%, due 10/29/25		42,000,000		41,081,425
4.570%, due 05/01/25¹		130,000,000		130,000,000
1 day USD SOFR + 0.260%, 4.620%, due 05/01/25^1,2		75,000,000		75,000,000
1 day USD SOFR + 0.300%, 4.660%, due 05/01/25^1,2		50,000,000		50,000,000
1 day USD SOFR + 0.300%, 4.660%, due 05/01/25^1,2		100,000,000		100,000,000
Sheffield Receivables Co. LLC
4.370%, due 05/06/25²		57,000,000		56,965,404
4.380%, due 05/09/25²		12,000,000		11,988,320
Starbird Funding Corp. 4.370%, due 05/09/25²		94,000,000		93,908,716
Thunder Bay Funding LLC
4.320%, due 08/27/25²		42,000,000		41,405,280
4.360%, due 07/03/25		25,000,000		24,809,250
4.640%, due 05/01/25¹		75,000,000		75,000,000
Versailles Commercial Paper LLC 4.480%, due 05/01/25¹		108,000,000		108,000,000
Victory Receivables Corp.
4.370%, due 05/09/25²		85,000,000		84,917,456
4.370%, due 06/02/25²		85,000,000		84,669,822
4.380%, due 05/06/25²		39,000,000		38,976,275
4.420%, due 07/21/25²		84,000,000		83,164,620

				2,214,166,177


Banking-non-U.S.34.8%
ANZ New Zealand International Ltd. 4.530%, due 05/06/25²		98,000,000		97,938,342
Australia & New Zealand Banking Group Ltd.
4.300%, due 07/07/25²		127,000,000		125,983,647
4.470%, due 06/16/25²		127,000,000		126,274,618
4.520%, due 06/02/25²		84,000,000		83,662,507
4.560%, due 05/01/25¹		73,000,000		73,000,000
4.570%, due 05/01/25^1,2		24,000,000		24,000,000
Bank of Montreal
1 day USD SOFR + 0.370%, 4.730%, due 05/01/25¹		30,000,000		30,000,000
Barclays Bank PLC
4.400%, due 07/08/25²		125,000,000		123,961,111
4.410%, due 07/03/25²		127,000,000		126,019,877
4.440%, due 08/01/25²		125,000,000		123,581,667
4.510%, due 05/14/25²		92,000,000		91,850,168
Commonwealth Bank of Australia
4.500%, due 05/01/25¹		72,000,000		71,997,123
4.510%, due 05/01/25¹		100,000,000		100,000,000
4.510%, due 05/01/25¹		128,000,000		128,000,000
4.610%, due 05/01/25¹		50,000,000		50,000,000
4.620%, due 05/01/25¹		100,000,000		100,000,000
4.640%, due 05/01/25¹		84,000,000		84,000,000
Cooperatieve Rabobank UA 4.310%, due 09/05/25		89,250,000		87,892,979
DBS Bank Ltd.
4.340%, due 06/03/25²		78,000,000		77,689,690


	Face amount		Value
Commercial paper(continued)
Banking-non-U.S.(continued)
4.350%, due 05/20/25²	$	16,000,000	$	15,963,267
4.380%, due 08/04/25²		125,000,000		123,555,208
4.520%, due 05/27/25²		91,000,000		90,702,936
DNB Bank ASA
4.280%, due 05/07/25²		100,000,000		99,928,667
4.290%, due 07/29/25²		125,000,000		123,674,271
4.300%, due 07/21/25²		73,000,000		72,293,725
4.310%, due 08/25/25²		71,000,000		70,013,968
4.330%, due 07/29/25²		59,000,000		58,368,421
DZ Bank AG Deutsche Zentral-Genossenschaftsbank 4.320%, due 05/01/25²		325,000,000		325,000,000
Erste Finance Delaware LLC
4.330%, due 05/01/25²		28,000,000		28,000,000
4.330%, due 05/06/25²		280,000,000		279,831,611
4.330%, due 05/07/25²		475,000,000		474,657,209
Federation des Caisses Desjardins du Quebec 4.350%, due 05/07/25²		400,000,000		399,710,000
Mizuho Bank Ltd.
4.370%, due 08/07/25²		125,000,000		123,512,986
4.375%, due 06/12/25²		100,000,000		99,489,583
4.395%, due 07/07/25²		125,000,000		123,977,552
4.500%, due 05/07/25²		123,000,000		122,907,750
4.515%, due 05/20/25²		125,000,000		124,702,135
National Australia Bank Ltd.
4.500%, due 05/21/25²		125,000,000		124,687,500
4.600%, due 05/01/25¹		99,000,000		99,000,000
1 day USD SOFR + 0.240%, 4.600%, due 05/01/25^1,2		125,000,000		125,000,000
Natixis SA 4.530%, due 05/12/25		125,000,000		124,826,979
Nordea Bank Abp
4.330%, due 08/18/25²		78,000,000		76,977,398
4.560%, due 05/01/25^1,2		127,000,000		127,000,000
1 day USD SOFR + 0.200%, 4.560%, due 05/01/25^1,2		62,000,000		62,000,000
NRW Bank 4.325%, due 05/27/25²		37,000,000		36,884,426
Oversea-Chinese Banking Corp. Ltd. 4.350%, due 06/11/25²		134,000,000		133,336,142
Podium Funding Trust
4.350%, due 07/14/25		100,000,000		99,105,833
4.360%, due 10/23/25		84,000,000		82,219,667
4.370%, due 07/23/25		50,000,000		49,496,236
4.380%, due 07/28/25		50,000,000		49,464,667
4.440%, due 07/07/25		50,000,000		49,586,833
4.520%, due 05/27/25		30,000,000		29,902,067
4.610%, due 05/01/25¹		100,000,000		100,000,000
Skandinaviska Enskilda Banken AB
1 day USD SOFR + 0.180%, 4.540%, due 05/01/25^1,2		125,000,000		125,000,000
4.560%, due 05/01/25¹		73,000,000		73,000,000
4.680%, due 05/01/25^1,2		33,000,000		33,000,000
4.680%, due 05/01/25^1,2		125,000,000		125,000,000
Sumitomo Mitsui Banking Corp. 4.365%, due 07/09/25²		125,000,000		123,954,219

Prime CNAV Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
Commercial paper(concluded)
Banking-non-U.S.(concluded)
Sumitomo Mitsui Trust 4.430%, due 07/17/25²	$	125,000,000	$	123,815,590
Sumitomo Mitsui Trust Bank Ltd.
4.320%, due 08/25/25²		125,000,000		123,260,000
4.330%, due 08/25/25²		125,000,000		123,255,972
4.390%, due 07/15/25²		60,000,000		59,451,250
4.430%, due 07/23/25²		123,000,000		121,743,726
4.430%, due 07/29/25²		60,000,000		59,342,883
Svenska Handelsbanken AB
4.310%, due 07/09/25²		128,000,000		126,942,613
4.560%, due 05/01/25¹		125,000,000		125,000,000
1 day USD SOFR + 0.200%, 4.560%, due 05/01/25^1,2		74,000,000		74,000,000
4.640%, due 05/01/25¹		125,000,000		125,000,000
Swedbank AB
4.335%, due 07/14/25²		63,000,000		62,438,618
4.355%, due 08/25/25²		64,000,000		63,101,902
4.360%, due 07/10/25²		125,000,000		123,940,278
4.560%, due 05/01/25¹		91,000,000		91,000,000
1 day USD SOFR + 0.250%, 4.610%, due 05/01/25^1,2		101,000,000		101,000,000
4.640%, due 05/01/25¹		125,000,000		125,000,000
United Overseas Bank Ltd.
4.320%, due 05/29/25²		91,000,000		90,694,240
4.530%, due 05/01/25¹		60,000,000		59,997,683
4.530%, due 05/01/25¹		125,000,000		125,000,000
1 day USD SOFR + 0.230%, 4.590%, due 05/01/25^1,2		100,000,000		100,000,000
Westpac Banking Corp.
4.580%, due 05/01/25^1,2		125,000,000		125,000,000
4.620%, due 05/01/25^1,2		125,000,000		125,000,000
4.760%, due 05/01/25^1,2		125,000,000		125,000,000

				8,710,567,740


Banking-U.S.1.9%
Bedford Row Funding Corp.
4.300%, due 08/07/25²		50,000,000		49,414,722
4.440%, due 06/12/25²		99,000,000		98,487,180
Collateralized Commercial Paper FLEX Co. LLC 4.660%, due 05/01/25¹		76,000,000		76,000,000
Collateralized Commercial Paper V Co. LLC
4.640%, due 05/01/25¹		125,000,000		125,000,000
4.660%, due 05/01/25¹		125,000,000		125,000,000

				473,901,902
Total commercial paper (cost$11,398,635,819)				11,398,635,819

Time deposits3.6%
Banking-non-U.S.3.6%
ABN AMRO Bank NV 4.310%, due 05/01/25		650,000,000		650,000,000
Credit Agricole Corporate & Investment Bank SA 4.310%, due 05/01/25		48,000,000		48,000,000
Mizuho Bank Ltd. 4.330%, due 05/01/25		195,000,000		195,000,000
Total time deposits (cost$893,000,000)				893,000,000


	Face amount		Value
Repurchase agreements37.8%
Repurchase agreement dated 04/01/25 with BofA Securities, Inc., 4.980% due 08/04/25, collateralized by $27,559,000 various asset-backed convertible bonds, 2.000% to 8.000% due 05/30/25 to 04/01/55; (value$26,250,616); proceeds: $25,100,292³	$	25,000,000	$	25,000,000
Repurchase agreement dated 04/30/25 with BNP Paribas Securities Corp., 4.460% due 05/01/25, collateralized by $53,295,800 various asset-backed convertible bonds, 4.375% to 12.750% due 05/15/25 to 12/31/79; (value$53,814,921); proceeds: $50,006,194		50,000,000		50,000,000
Repurchase agreement dated 06/03/24 with J.P. Morgan Securities LLC, 4.660% due 06/04/25, collateralized by $51,684,000 various asset-backed convertible bonds, zero coupon to 2.500% due 09/15/25 to 06/01/31; (value$55,000,249); proceeds: $52,142,306³		50,000,000		50,000,000
Repurchase agreement dated 06/03/24 with J.P. Morgan Securities LLC, 4.560% due 05/07/25, collateralized by $46,102,000 various asset-backed convertible bonds, 0.250% to 5.750% due 08/01/26 to 06/01/54; (value$59,400,089); proceeds: $56,264,040³		54,000,000		54,000,000
Repurchase agreement dated 04/01/25 with BofA Securities, Inc., 4.980% due 08/04/25, collateralized by $70,129,740 various asset-backed convertible bonds, zero coupon to 11.000% due 05/15/25 to 12/31/99; (value$68,250,380); proceeds: $65,260,758³		65,000,000		65,000,000
Repurchase agreement dated 06/03/24 with J.P. Morgan Securities LLC, 4.560% due 05/07/25, collateralized by $85,302,114 various asset-backed convertible bonds, zero coupon to 15.000% due 08/01/26 to 12/31/99; (value$81,972,578); proceeds: $78,144,500³		75,000,000		75,000,000
Repurchase agreement dated 06/03/24 with J.P. Morgan Securities LLC, 4.700% due 07/29/25, collateralized by $105,487,000 various asset-backed convertible bonds, 2.820% to 8.000% due 09/07/25 to 12/09/54; (value$105,000,274); proceeds: $104,321,389³		100,000,000		100,000,000
Repurchase agreement dated 04/01/25 with BofA Securities, Inc., 4.980% due 08/04/25, collateralized by $195,363,558 various asset-backed convertible bonds, 1.750% to 13.375% due 08/22/25 to 05/15/87; (value$183,750,002); proceeds: $175,702,042³		175,000,000		175,000,000
Repurchase agreement dated 04/30/25 with BNP Paribas Securities Corp., 4.420% due 05/01/25, collateralized by $185,609,314 various asset-backed convertible bonds, 0.750% to 8.000% due 05/23/25 to 12/01/96; (value$183,902,287); proceeds: $175,021,486		175,000,000		175,000,000

Prime CNAV Master Fund

Portfolio of investmentsApril 30, 2025


	Face amount		Value
Repurchase agreements(concluded)
Repurchase agreement dated 04/30/25 with Barclays Bank PLC, 4.370% due 05/01/25, collateralized by $1,545,976,184 U.S. Treasury Bond Strips, zero coupon due 05/15/26 to 02/15/54, $133,970,800 U.S. Treasury Bond Principal Strips, zero coupon due 11/15/54, $759,259,900 U.S. Treasury Inflation Index Bonds, 0.125% to 3.875% due 01/15/27 to 02/15/54 and $554,700,300 U.S. Treasury Inflation Index Notes, 0.125% to 2.125% due 10/15/25 to 01/15/35; (value$2,244,000,011); proceeds: $2,200,267,056	$	2,200,000,000	$	2,200,000,000
Repurchase agreement dated 04/30/25 with Fixed Income Clearing Corp., 4.370% due 05/01/25, collateralized by $50,000,000 U.S. Treasury Notes, 0.250% due 06/30/25, $143,381,700 U.S. Treasury Bill, zero coupon due 06/24/25 and $5,188,871,100 U.S. Treasury Inflation Index Notes, 0.375% to 2.375% due 07/15/25 to 07/15/34; (value$6,630,000,212); proceeds: $6,500,789,028		6,500,000,000		6,500,000,000
Total repurchase agreements (cost$9,469,000,000)				9,469,000,000
Total investments (cost$24,851,551,984 which approximates cost for federal income tax purposes)99.2%				24,851,551,984

Other assets in excess of liabilities0.8%				195,730,750
Net assets100.0%			$	25,047,282,734

Prime CNAV Master Fund

Portfolio of investmentsApril 30, 2025

Fair valuation summary


Description	Unadjusted quoted prices in active markets for identical investments (Level 1)	Other significant observable inputs (Level 2)		Unobservable inputs (Level 3)	Total
Assets

Certificates of deposit	$	$	3,090,916,165	$	$	3,090,916,165
Commercial paper			11,398,635,819			11,398,635,819
Time deposits			893,000,000			893,000,000
Repurchase agreements			9,469,000,000			9,469,000,000
Total	$	$	24,851,551,984	$	$	24,851,551,984

At April 30, 2025, there were no transfers in or out of Level 3.

Portfolio footnotes

Security exempt from registration pursuant to Rule 144A under the Securities Act of 1933. These securities are considered liquid, unless noted otherwise, and may be resold in transactions exempt from registrations, normally to qualified institutional buyers. Securities exempt from registration pursuant to Rule 144A, in the amount of $8,620,459,906, represented 34.4% of the Master Funds net assets at period end.

See accompanying notes to financial statements.

Glossary of terms used in the Portfolio of investments

Portfolio acronyms:


SOFR		Secured Overnight Financing Rate

See accompanying notes to financial statements.

Master Trust

Statement of assets and liabilities

April 30, 2025


	Government Master Fund		Treasury Master Fund		100% US Treasury Master Fund		Prime CNAV Master Fund
Assets:
Investments, at cost
Investments	$	15,129,167,712	$	21,681,534,070	$	10,003,302,659	$	15,382,551,984
Repurchase agreements		7,984,000,000		18,813,000,000				9,469,000,000

Investments, at value
Investments		15,129,167,712		21,681,534,070		10,003,302,659		15,382,551,984
Repurchase agreements		7,984,000,000		18,813,000,000				9,469,000,000
Cash		1,155,411,513		1,318,620,170		51,537,100		489,352,730
Receivable for interest		19,022,610		15,402,726		1,934,541		31,965,155
Deferred offering costs						34,744
Total assets		24,287,601,835		41,828,556,966		10,056,809,044		25,372,869,869

Liabilities:
Payable for investments purchased		242,795,860		407,976,650		104,481,825		323,555,208
Payable to affiliate		2,051,310		3,287,930		773,495		2,031,927
Payable to custodian						52,858
Accrued expenses and other liabilities						107,296
Total liabilities		244,847,170		411,264,580		105,415,474		325,587,135
Net assets, at value	$	24,042,754,665	$	41,417,292,386		$9,951,393,570	$	25,047,282,734

See accompanying notes to financial statements.

Master Trust

Statement of operations

For the year ended April 30, 2025


	Government Master Fund		Treasury Master Fund		100% US Treasury Master Fund			Prime CNAV Master Fund
Investment income:
Interest		$1,274,764,759		$2,064,571,785		$319,024,645			$1,064,733,126
Expenses:
Investment advisory and administration fees		26,077,800		41,959,182		6,840,810			21,645,348
Custody and fund accounting fees						118,544
Trustees fees		111,915		174,772		95,226			101,286
Professional services fees						170,630
Printing and shareholder report fees						15,261
Amortization of offering costs						39,155
Other expenses						60,888
Total expenses		26,189,715		42,133,954		7,340,514			21,746,634
Less: Fee waivers and/or Trustees fees reimbursement by administrator						(452,014	)
Net expenses		26,189,715		42,133,954		6,888,500			21,746,634
Net investment income (loss)		1,248,575,044		2,022,437,831		312,136,145			1,042,986,492
Net realized gain (loss)		1,158,182				67,921			66,584
Net increase (decrease) in net assets resulting from operations		$1,249,733,226		$2,022,437,831		$312,204,066			$1,043,053,076

See accompanying notes to financial statements.

Master Trust

Statement of changes in net assets


	Government Master Fund
	For the years ended April 30,
	2025			2024
From operations:

Net investment income (loss)		$1,248,575,044			$1,049,914,890
Net realized gain (loss)		1,158,182
Net increase (decrease) in net assets resulting from operations		1,249,733,226			1,049,914,890
Net increase (decrease) in net assets from beneficial interest transactions		(530,449,132	)		3,038,590,921
Net increase (decrease) in net assets		719,284,094			4,088,505,811
Net assets:

Beginning of year		23,323,470,571			19,234,964,760
End of year		$24,042,754,665			$23,323,470,571


	Treasury Master Fund
	For the years ended April 30,
	2025		2024
From operations:

Net investment income (loss)		$2,022,437,831		$1,933,416,360
Net realized gain (loss)
Net increase (decrease) in net assets resulting from operations		2,022,437,831		1,933,416,360
Net increase (decrease) in net assets from beneficial interest transactions		297,824,288		2,285,766,889
Net increase (decrease) in net assets		2,320,262,119		4,219,183,249
Net assets:

Beginning of year		39,097,030,267		34,877,847,018
End of year		$41,417,292,386		$39,097,030,267


	100% US Treasury Master Fund
	For the year ended April 30, 2025		For the period from March 13, 2024¹ to April 30, 2024
From operations:

Net investment income (loss)		$312,136,145		$175,126
Net realized gain (loss)		67,921
Net increase (decrease) in net assets resulting from operations		312,204,066		175,126
Net increase (decrease) in net assets from beneficial interest transactions		9,614,090,492		24,923,886
Net increase (decrease) in net assets		9,926,294,558		25,099,012
Net assets:

Beginning of year		25,099,012
End of year	$	9,951,393,570	$	25,099,012

¹	Commencement of operations.

See accompanying notes to financial statements.

Master Trust

Statement of changes in net assets


	Prime CNAV Master Fund
	For the years ended April 30,
	2025			2024
From operations:

Net investment income (loss)		$1,042,986,492			$646,042,580
Net realized gain (loss)		66,584			428
Net increase (decrease) in net assets resulting from operations		1,043,053,076			646,043,008
Net increase (decrease) in net assets from beneficial interest transactions		10,647,278,707	*		3,744,622,503
Net increase (decrease) in net assets		11,690,331,783			4,390,665,511
Net assets:

Beginning of year		13,356,950,951			8,966,285,440
End of year		$25,047,282,734			$13,356,950,951

*	Includes $8,370,789,961 attributed to the Plan of Reorganization pursuant to which Prime Master Fund transferred its assets to Prime CNAV Master Fund. Refer to the Reorganization of Funds in the notes to financial statements for further details.

See accompanying notes to financial statements.

Government Master Fund

Financial highlights

Selected financial data throughout each year is presented below:


	Years ended April 30,
	2025			2024			2023			2022			2021
Ratios to average net assets:
Expenses before fee waivers		0.10	%		0.10	%		0.10	%		0.10	%		0.10	%
Expenses after fee waivers		0.10	%		0.10	%		0.04	%		0.06	%		0.10	%
Net investment income (loss)		4.77	%		5.25	%		3.78	%		0.02	%		0.09	%
Supplemental data:
Total investment return¹		4.90	%		5.39	%		3.14	%		0.03	%		0.08	%
Net assets, end of year (000s)	$	24,042,755		$	23,323,471		$	19,234,965		$	4,297,678		$	8,822,693

The total investment return for the Master Funds is calculated using geometric average return. The Master Funds issue ownership interests, rather than shares, to the feeder funds. Individual investors invest only into the feeder funds. Feeder fund total investment return is calculated as described within the feeder fund financial highlights and may differ from geometric average return of the Master Fund.

See accompanying notes to financial statements.

Treasury Master Fund

Financial highlights

Selected financial data throughout each year is presented below:


	Years ended April 30,
	2025			2024			2023			2022			2021
Ratios to average net assets:
Expenses before fee waivers		0.10	%		0.10	%		0.10	%		0.10	%		0.10	%
Expenses after fee waivers		0.10	%		0.10	%		0.10	%		0.06	%		0.09	%
Net investment income (loss)		4.76	%		5.24	%		3.23	%		0.04	%		0.09	%
Supplemental data:
Total investment return¹		4.89	%		5.36	%		3.06	%		0.04	%		0.08	%
Net assets, end of year (000s)	$	41,417,292		$	39,097,030		$	34,877,847		$	21,681,389		$	32,675,191

See accompanying notes to financial statements.

100% US Treasury Master Fund

Financial highlights

Selected financial data throughout each period is presented below:


	Year ended April 30, 2025			For the period from March 13, 2024¹ to April 30, 2024
Ratios to average net assets:
Expenses before fee waivers		0.11	%		1.73	%²
Expenses after fee waivers		0.10	%		0.10	%²
Net investment income (loss)		4.53	%		5.26	%²
Supplemental data:
Total investment return³		4.95	%		0.70	%
Net assets, end of period (000s)	$	9,951,394		$	25,099

¹	Commencement of operations.

²	Annualized.

See accompanying notes to financial statements.

Prime CNAV Master Fund

Financial highlights

Selected financial data throughout each year is presented below:


	Years ended April 30,
	2025			2024			2023			2022			2021
Ratios to average net assets:
Expenses		0.10	%		0.10	%		0.10	%		0.10	%		0.10	%
Net investment income (loss)		4.80	%		5.41	%		3.84	%		0.08	%		0.19	%
Supplemental data:
Total investment return¹		5.01	%		5.55	%		3.27	%		0.09	%		0.17	%
Net assets, end of year (000s)	$	25,047,283		$	13,356,951		$	8,966,285		$	1,908,435		$	4,449,407

See accompanying notes to financial statements.

Master Trust

Notes to financial statements

Organization and significant accounting policies

Government Master Fund, Treasury Master Fund, 100% US Treasury Master Fund, and Prime CNAV Master Fund (each a Master Fund, collectively, the Master Funds) are each registered with the US Securities and Exchange Commission (SEC) under the Investment Company Act of 1940, as amended (1940 Act), as a diversified series of Master Trust, an open-end management investment company organized as a Delaware statutory trust on June 12, 2007. The Trust is a series mutual fund with four series.

Treasury Master Fund commenced operations on August 28, 2007. Prime CNAV Master Fund commenced operations on January 19, 2016, Government Master Fund commenced operations on June 24, 2016, and 100% US Treasury Master Fund commenced operations on March 13, 2024.

UBS Asset Management (Americas) LLC (UBS AM) is the investment advisor and administrator for the Master Funds. UBS AM is an indirect wholly owned subsidiary of UBS Group AG. UBS Group AG is an internationally diversified organization with headquarters in Zurich, Switzerland. UBS Group AG operates in many areas of the financial services industry.

Master Trust accounts separately for the assets, liabilities and operations of each series. Expenses directly attributable to each series are charged to that series operations; expenses which are applicable to all series are allocated among them on a pro rata basis.

Each Master Fund may issue any number of interests and each interest shall have a par value of $0.001 per interest. The interests of a Master Fund shall represent a proportional beneficial interest in the net assets belonging to that series. Each holder of interests of a Master Fund shall be entitled to receive his or her pro rata share of all distributions made with respect to such Master Fund according to the investors ownership percentage of such Master Fund on the record date established for payment. Upon redemption of interests, an investor shall be paid solely out of the assets and property of such Master Fund. Beneficial interests in the Master Funds are not registered under the Securities Act of 1933, as amended, since such interests are issued in private placement transactions.

In the normal course of business, the Master Funds may enter into contracts that contain a variety of representations that provide indemnification for certain liabilities. The Master Funds maximum exposure under these arrangements is unknown, as this would involve future claims that may be made against the Master Funds that have not yet occurred. However, the Master Funds have not had any prior claims or losses pursuant to these contracts and expect the risk of loss to be remote.

The Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) is the exclusive reference of authoritative US generally accepted accounting principles (US GAAP) recognized by the FASB to be applied by nongovernmental entities. Rules and interpretive releases of the SEC under authority of federal laws are also sources of authoritative US GAAP for SEC registrants. The Master Funds financial statements are prepared in accordance with US GAAP, which may require the use of management estimates and assumptions. Actual results could differ from those estimates.

In this reporting period, the Master Funds adopted FASB Accounting Standards Update 2023-07, Segment Reporting (Topic 280)Improvements to Reportable Segment Disclosures (ASU 2023-07). Adoption of the new standard impacted financial statement disclosures only and did not affect the Master Funds financial position or the results of their operations. An operating segment is defined in Topic 280 as a component of a public entity that engages in business activities from which it may recognize revenues and incur expenses, has operating results that are regularly reviewed by the public entitys chief operating decision maker (CODM) to make decisions about resources to be allocated to the segment and assess its performance, and has discrete financial information available. The Master Funds portfolio management team acts as the Master Funds CODM. Each of the Master Funds represents a single operating segment, as the CODM monitors the operating results of each Master Fund as a

Master Trust

Notes to financial statements

whole, and the Master Funds long-term strategic asset allocation is pre-determined in accordance with the Master Funds single investment objective which is executed by the Master Funds portfolio managers as a team. The financial information in the form of the Master Funds portfolio composition, total returns, expense ratios and changes in net assets (i.e., changes in net assets resulting from operations, subscriptions and redemptions) which are used by the CODM to assess the segments performance versus the Master Funds comparative benchmarks and to make resource allocation decisions for the Master Funds single segment, is consistent with that presented within the Master Funds financial statements. Segment assets are reflected on the accompanying statements of assets and liabilities as total assets and significant segment expenses are listed on the accompanying statements of operations.

The following is a summary of significant accounting policies:

Valuation of investments

Under Rule 2a-7, Government Master Fund, Treasury Master Fund, 100% US Treasury Master Fund, and Prime CNAV Master Fund have adopted certain policies that enable them to use the amortized cost method of valuation. Government Master Fund, Treasury Master Fund and 100% US Treasury Master Fund, have adopted a policy to operate as government money market funds. Under Rule 2a-7, a government money market fund invests 99.5% or more of its total assets in cash, government securities, and/or repurchase agreements that are collateralized fully (i.e., collateralized by cash and/or government securities).Prime CNAV Master Fund operates as a retail money market fund. Under Rule 2a-7, a retail money market fund is a money market fund that has policies and procedures reasonably designed to limit all beneficial owners of the fund to natural persons. As government money market funds and as a retail money market fund, Government Master Fund, Treasury Master Fund, 100% US Treasury Master Fund, and Prime CNAV Master Fund value their investments at amortized cost unless UBS AM, as the valuation designee appointed by Master Trusts Board of Trustees (the Board) pursuant to Rule 2a-5 under the 1940 Act, determines that this does not represent fair value. Periodic review and monitoring of the valuation of securities held by Government Master Fund, Treasury Master Fund, 100% US Treasury Master Fund, and Prime CNAV Master Fund is performed in an effort to ensure that amortized cost approximates market value.

The Board has designated UBS AM as the valuation designee pursuant to Rule 2a-5 under the 1940 Act and delegated to UBS AM the responsibility for making fair value determinations with respect to portfolio holdings. UBS AM, as the valuation designee, is responsible for periodically assessing any material risks associated with the determination of the fair value of investments; establishing and applying fair value methodologies; testing the appropriateness of fair value methodologies; and overseeing and evaluating third-party pricing services. UBS AM has the Equities, Fixed Income, and Multi-Asset Valuation Committee (the VC) to assist with its designated responsibilities as valuation designee with respect to the Master Funds portfolios of investments. The types of investments for which such fair value pricing may be necessary include, but are not limited to: investments of an issuer that has entered into a restructuring; fixed-income investments that have gone into default and for which there is no current market value quotation; Section 4(a)(2) commercial paper; investments that are restricted as to transfer or resale; illiquid investments; and investments for which the prices or values available do not, in the judgment of the VC, represent current market value. The need to fair value a Master Funds portfolio of investments may also result from low trading volume in foreign markets or thinly traded investments. Various factors may be reviewed in order to make a good faith determination of an investments fair value. These factors include, but are not limited to, fundamental analytical data relating to the investment; the nature and duration of restrictions on disposition of the investment; and the evaluation of forces which influence the market in which the investments are purchased and sold.

Each Master Funds portfolio holdings may also consist of shares of other investment companies in which the Master Fund invests. The value of each such open-end investment company will generally be its net asset value at the time a Master Funds beneficial interests are priced. Pursuant to each Master Funds use of the practical expedient within ASC Topic 820, investments in non-registered investment companies and/or investments in investment companies without publicly published prices are also valued at the daily net asset value. Each investment company generally values investments in a manner as described in that investment companys prospectus or similar documents.

Master Trust

Notes to financial statements

US GAAP requires disclosure regarding the various inputs that are used in determining the value of each Master Funds investments. These inputs are summarized into the three broad levels listed below:

Level 1Unadjusted quoted prices in active markets for identical investments.

Level 2Other significant observable inputs, including but not limited to, quoted prices for similar investments, interest rates, prepayment speeds and credit risks.

Level 3Unobservable inputs inclusive of each Master Funds own assumptions in determining the fair value of investments.

A fair value hierarchy table has been included near the end of each Master Funds Portfolio of investments.

Liquidity feeConsistent with Rule 2a-7, the Board is permitted to impose a liquidity fee on redemptions from Prime CNAV Master Fund under certain circumstances. Liquidity fees would reduce the amount an interest holder receives upon redemption of its beneficial interests. Prime CNAV Master Fund retains the liquidity fees for the benefit of its remaining interest holders. For the period ended April 30, 2025, the Board of Prime CNAV Master Fund did not impose any liquidity fees.

By operating as government money market funds, Government Master Fund, Treasury Master Fund and 100% US Treasury Master Fund are exempt from requirements that permit the imposition of a liquidity fee. While the Board may elect to subject Government Master Fund, Treasury Master Fund and 100% US Treasury Master Fund to liquidity fee requirements in the future, the Board has not elected to do so at this time.

Repurchase agreementsEach Master Fund (except 100% US Treasury Master Fund) may purchase securities or other obligations from a bank or securities dealer (or its affiliate), subject to the sellers agreement to repurchase them at an agreed upon date (or upon demand) and price. Such Master Funds maintain custody of the underlying obligations prior to their repurchase, either through their regular custodian or through a special tri-party custodian or sub-custodian that maintains a separate account for both the Master Funds and their counterparty. The underlying collateral is valued daily in an effort to ensure that the value, including accrued interest, is at least equal to the repurchase price.

Repurchase agreements carry certain risks not associated with direct investments in securities, including a possible decline in the market value of the underlying obligations. If their value becomes less than the repurchase price, plus any agreed-upon additional amount, the counterparty must provide additional collateral so that the collateral is at least equal to the repurchase price plus any agreed-upon additional amount. The difference between the total amount to be received upon repurchase of the obligations and the price that was paid by a fund upon acquisition is accrued as interest and included in its net investment income. In the event of default of the obligation to repurchase, the Master Funds generally have the right to liquidate the collateral and apply the proceeds in satisfaction of the obligation. Repurchase agreements involving obligations other than US government securities (such as commercial paper, corporate bonds, equities and mortgage loans) may be subject to special risks and may not have the benefit of certain protections in the event of counterparty insolvency. Moreover, repurchase agreements secured by obligations that are not eligible for direct investment under Rule 2a-7 or a funds investment strategies and limitations may require the Master Fund to promptly dispose of such collateral if the seller or guarantor becomes insolvent. If the seller (or sellers guarantor, if any) becomes insolvent, the Master Funds may suffer delays, costs and possible losses in connection with the disposition or retention of the collateral. Under certain circumstances, in the event of default or bankruptcy by the other party to the agreement, realization and/or retention of the collateral may be subject to legal proceedings. Each such Master Fund intends to enter into repurchase agreements only in transactions with counterparties believed by UBS AM to present minimal credit risk.

Master Trust

Notes to financial statements

The relevant Master Funds may participate in joint repurchase agreement transactions with other funds managed or advised by UBS AM. Government Master Fund, Treasury Master Fund and Prime CNAV Master Fund may engage in repurchase agreements as part of normal investing strategies.

Under certain circumstances, a Master Fund may engage in a repurchase agreement transaction with a yield of zero in order to invest cash amounts remaining in its portfolio at the end of the day in order to avoid having the Master Fund potentially exposed to a fee for uninvested cash held in a business account at a bank.

Investment transactions and investment incomeInvestment transactions are recorded on the trade date. Realized gains and losses from investment transactions are calculated using the identified cost method. Interest income is recorded on an accrual basis. Discounts are accreted and premiums are amortized as adjustments to interest income and the identified cost of investments.

Concentration of riskThe ability of the issuers of the debt securities held by the Master Funds to meet their obligations may be affected by economic, political and other developments particular to a specific industry, country, state or region.

Deferred offering costsOffering costs consist primarily of legal fees and other costs incurred with organizing and registering a fund. With respect to 100% US Treasury Master Fund, deferred offering costs are amortized over a period of 12 months.

Investment advisor and administrator

UBS AM serves as the investment advisor and administrator to each Master Fund pursuant to an investment advisory and administration contract (Management Contract) approved by the Board. In accordance with the Management Contract, each Master Fund pays UBS AM an investment advisory and administration fee (management fee), which is accrued daily and paid monthly, at the below annual rates, as a percentage of each Master Funds average daily net assets:


Average daily net assets	Annual rate
Up to $30 billion		0.1000	%
In excess of $30 billion up to $40 billion		0.0975
In excess of $40 billion up to $50 billion		0.0950
In excess of $50 billion up to $60 billion		0.0925
Over $60 billion		0.0900

At April 30, 2025, the Master Funds owed UBS AM for investment advisory and administration services, net of waivers (if any), as follows:


Fund	Net amount owed to UBS AM
Government Master Fund	$	2,051,310
Treasury Master Fund		3,287,930
100% US Treasury Master Fund		773,495
Prime CNAV Master Fund		2,031,927

In exchange for these fees, for each Master Fund except 100% US Treasury Master Fund, UBS AM has agreed to bear all of the Master Funds expenses other than interest (except interest on borrowings), taxes, extraordinary costs and the cost of securities purchased and sold by such Master Funds, including any transaction costs. Although UBS AM is not obligated to pay the fees and expenses of such Master Funds independent trustees, it is contractually obligated to reduce its management fee in an amount equal to those fees and expenses. UBS AM estimates that these fees and expenses will be less than 0.01% of each Master Funds average daily net assets.

Master Trust

Notes to financial statements

With respect to 100% US Treasury Master Fund, such Master Fund will bear all expenses not specifically assumed by UBS AM incurred in its operations and the offering of its shares. UBS AM has contractually agreed to waive its management fees and/or reimburse expenses so that this Master Funds ordinary total operating expenses through August 31, 2025 (excluding, as applicable, (i) dividend expense, borrowing costs, and interest expense relating to short sales and (ii) investments in other investment companies, interest, taxes, brokerage commissions, expenses related to interest holders meetings and extraordinary expenses) do not exceed 0.10%. The contractual fee waiver agreement also provides that UBS AM is entitled to be reimbursed for any fees it waives and expenses it reimburses to the extent such reimbursement can be made during the three years following the period during which such fee waivers and expense reimbursements were made, provided that the reimbursement of UBS AM by 100% US Treasury Master Fund will not cause such Master Fund to exceed the lesser of any applicable expense limit that is in place for such Master Fund (i) at the time of the waiver or reimbursement or (ii) at the time of the recoupment. The fee waiver/expense reimbursement agreement may be terminated by the Trusts board at any time and also will terminate automatically upon the expiration or termination of such Master Funds management contract with UBS AM.

During the period ended April 30, 2025, UBS AM waived the below amount, which is subject to future recoupment:


Fund	Fee waiver expense Reimbursement subject to repayment		Expires April 30, 2027		Expires April 30, 2028
100% US Treasury Master Fund	$	506,185	$	54,171	$	452,014

Beneficial interest transactions


Government Master Fund

	For the years ended April 30,
	2025			2024
Contributions	$	92,715,049,160		$	56,516,921,636
Withdrawals		(93,245,498,292	)		(53,478,330,715	)
Net increase (decrease) in beneficial interest	$	(530,449,132	)	$	3,038,590,921

Treasury Master Fund

	For the years ended April 30,
	2025			2024
Contributions	$	83,950,122,114		$	82,757,159,468
Withdrawals		(83,652,297,826	)		(80,471,392,579	)
Net increase (decrease) in beneficial interest	$	297,824,288		$	2,285,766,889

100% US Treasury Master Fund
	For the year ended April 30, 2025			For the period from March 13, 2024¹ to April 2024
Contributions	$	14,987,658,097		$	58,385,304
Withdrawals		(5,373,567,605	)		(33,461,418	)
Net increase (decrease) in beneficial interest	$	9,614,090,492		$	24,923,886

Commencement of operations.

Master Trust

Notes to financial statements


Prime CNAV Master Fund

	For the years ended April 30,
	2025			2024
Contributions	$	27,537,686,305	*	$	9,745,111,848
Withdrawals		(16,890,407,598	)		(6,000,489,345	)
Net increase (decrease) in beneficial interest	$	10,647,278,707		$	3,744,622,503

*	Includes $8,370,789,961 attributed to the Plan of Reorganization pursuant to which Prime Master Fund transferred its assets to Prime CNAV Master Fund. Refer to the Reorganization of Funds in the notes to financial statements for further details.

Federal tax status

Each Master Fund is considered a non-publicly traded partnership for federal income tax purposes under the Internal Revenue Code; therefore, no federal tax provision is necessary. As such, each investor in a Master Fund is treated as owning its proportionate share of the net assets, income, expenses, and realized and unrealized gains and losses of the Master Fund. UBS AM intends that each Master Funds assets, income and distributions will be managed in such a way that an investor in a Master Fund will be able to continue to qualify as a regulated investment company by investing its net assets through the Master Fund.

Aggregate cost for federal income tax purposes was substantially the same for book purposes.

ASC 740-10 Income TaxesOverall sets forth a minimum threshold for financial statement recognition of the benefit of a tax position taken or expected to be taken. The Master Funds have conducted an analysis and concluded, as of April 30, 2025, that there are no significant uncertain tax positions taken or expected to be taken that would require recognition in the financial statements. The Master Funds recognize interest and penalties, if any, related to uncertain tax positions as income tax expense in the Statement of operations. During the period ended April 30, 2025, the Funds did not incur any interest or penalties.

Each of the tax years in the four year period ended April 30, 2025 and since inception for 100% US Treasury Master Fund, remains subject to examination by the Internal Revenue Service and state taxing authorities.

Reorganization of Funds

Following the close of business August 23, 2024, the Target Fund reorganized into the existing Destination Fund within the Trust. The reorganization into the existing Destination Fund was as follows:


Target Fund	Destination Fund
Prime Master Fund		Prime CNAV Master Fund

Pursuant to an Agreement and Plan of Reorganization, the Target Fund transferred all of its property and assets to the Destination Fund. In exchange, the Destination Fund assumed all of the liabilities of the Target Fund and issued a proportionate interest to the Target Fund, as described below. The reorganization was accomplished by a tax-free exchange of the net assets of the Target Fund for a proportionate interest of the Destination Fund outstanding following the close of business on August 23, 2024. The allocated cost basis of the investments received from the Target Fund were carried forward to align ongoing reporting of the related feeder funds allocated realized and unrealized gains and losses with amounts distributable to feeder fund shareholders for tax purposes.


Target Fund	Destination Fund		Dollar Amount
Prime Master Fund		Prime CNAV Master Fund	$	8,370,789,961

Master Trust

Notes to financial statements

The net assets of the Target Fund, including unrealized appreciation (depreciation), were combined with those of the Destination Fund. These amounts were as follows:

Target Fund

Unrealized

Appreciation

Depreciation)

Target Fund

Net Assets

Destination Fund

Destination

Fund Net
Assets Prior to

Reorganization

Net Assets

After

Reorganization

Prime Master Fund

(1,124,223

)

8,370,789,961

Prime CNAV Master Fund

16,158,299,089

24,529,089,050

Assuming the reorganization had been completed as of the beginning of the annual reporting period of the accounting and performance survivor, the pro forma results of operations for the year ended April 30, 2025 would have been as follows (unaudited):

Destination Fund

Net Investment

Income (Loss)

Net Realized and

Change in

Unrealized Gain

(Loss)

Net Increase

(Decrease) in Net

Assets Resulting

from Operations

Prime CNAV Master Fund

1,333,168,738

(323,440

)

1,332,845,298

Master Trust

Report of independent registered public accounting firm

To the Interest holders and the Board of Trustees of Master Trust

Opinion on the Financial Statements

We have audited the accompanying statements of assets and liabilities of Master Trust (the Trust), (comprising Government Master Fund, Treasury Master Fund, Prime CNAV Master Fund, and 100% US Treasury Master Fund (collectively referred to as the Funds)), including the portfolios of investments, as of April 30, 2025, and the related statements of operations and changes in net assets, and the financial highlights for each of the periods indicated in the table below and the related notes (collectively referred to as the financial statements). In our opinion, the financial statements present fairly, in all material respects, the financial position of each of the Funds comprising Master Trust at April 30, 2025, the results of their operations, changes in net assets and financial highlights for each of the periods indicated in the table below, in conformity with U.S. generally accepted accounting principles.


Individual fund constituting the Master Trust	Statement of operations	Statements of changes in net assets	Financial highlights
Government Master Fund Treasury Master Fund Prime CNAV Master Fund	For the year ended April 30, 2025	For each of the two years in the period ended April 30, 2025	For each of the five years in the period ended April 30, 2025
100% US Treasury Master Fund	For the year ended April 30, 2025	For the year ended April 30, 2025 and for the period from March 13, 2024 (commencement of operations) through April 30, 2024	For the year ended April 30, 2025 and for the period from March 13, 2024 (commencement of operations) through April 30, 2024

Basis for Opinion

These financial statements are the responsibility of the Trusts management. Our responsibility is to express an opinion on each of the Funds financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Trust in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and in accordance with the relevant ethical requirements relating to our audit.

We conducted our audits in accordance with the auditing standards of the PCAOB and in accordance with auditing standards generally accepted in the United States of America. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. The Trust is not required to have, nor were we engaged to perform, an audit of the Trusts internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Trusts internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our procedures included confirmation of securities owned as of April 30, 2025, by correspondence with the custodian and brokers; when replies were not received from brokers, we performed other auditing procedures. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

We have served as the auditor of one or more UBS investment companies since 1978.

New York, New York

June 24, 2025

Master Trust

General information (unaudited)

Monthly portfolio holdings disclosure

The Master Funds file their complete schedules of portfolio holdings with the US Securities and Exchange Commission (SEC) each month on Form N-MFP. The Master Funds reports on Form N-MFP are available on the SECs Web site at http://www.sec.gov. The Master Funds make portfolio holdings information available to interest holders (and investors in the related feeder funds) on UBSs Web site at the following internet address: www.ubs.com/usmoneymarketfunds. A more limited portfolio holdings report for each Master Fund is available on a weekly basis at the same Web address. Investors also may find additional information about the Master Funds at the above referenced UBS Website internet address.

Proxy voting policies, procedures and record

You may obtain a description of each Funds (1) proxy voting policies, (2) proxy voting procedures and (3) information regarding how the Fund voted any proxies related to portfolio securities during the most recent 12-month period ended June 30 for which an SEC filing has been made, without charge, upon request by contacting the Fund directly at 1-800-647 1568, online on the Funds Web site: www.ubs.com/ubsam-proxy, or on the EDGAR Database on the SECs Web site (http://www.sec.gov).

Trustees

Virginia G. Breen

Richard R. Burt

Bernard H. Garil

Heather R. Higgins

Chair

David R. Malpass

Manager

UBS Asset Management (Americas) LLC

787 Seventh Avenue

New York, New York 10019

Placement Agent

UBS Asset Management (US) Inc.

787 Seventh Avenue

New York, New York 10019

This report is not to be used in connection with the offering of interests in the Funds unless accompanied or preceded by an offering document.

UBS Asset Management (Americas) LLC

787 Seventh Avenue

New York, New York 10019

Item 12. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not applicable to the registrant.

Item 13. Portfolio Managers of Closed-End Management Investment Companies.

Not applicable to the registrant.

Item 14. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

Not applicable to the registrant.

Item 15. Submission of Matters to a Vote of Security Holders.

The registrants Board has established a Nominating and Corporate Governance Committee. The Nominating and Corporate Governance Committee will consider nominees recommended by shareholders if a vacancy occurs among those board members who are not interested persons as defined in Section 2(a)(19) of the Investment Company Act of 1940, as amended. In order to recommend a nominee, a

shareholder should send a letter to the chair of the Nominating and Corporate Governance Committee, Richard R. Burt, care of the Secretary of the registrant at UBS Asset Management, UBS Building, One North Wacker Drive, Chicago, IL 60606, Attn: Keith A. Weller, Secretary, and indicate on the envelope Nominating and Corporate Governance Committee. The shareholders letter should state the nominees name and should include the nominees resume or curriculum vitae, and must be accompanied by a written consent of the individual to stand for election if nominated for the Board and to serve if elected by shareholders.

Item 16. Controls and Procedures.

(a)

The registrants principal executive officer and principal financial officer have concluded that the registrants disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940, as amended) are effective based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this document.

(b)

The registrants principal executive officer and principal financial officer are aware of no changes in the registrants internal control over financial reporting that occurred during the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrants internal control over financial reporting.

Item 17. Disclosure of Securities Lending Activities for Closed- End Management Investment Companies.

Not applicable to the registrant.

Item 18. Recovery of Erroneously Awarded Compensation.

Not applicable.

Item 19. Exhibits.

(a)

(1) Code of Ethics as required pursuant to Section 406 of the Sarbanes-Oxley Act of 2002 (and designated by registrant as a Code of Conduct) is filed herewith as Exhibit EX-99.CODE ETH.

(a)

(2) Any policy required by the listing standards adopted pursuant to Rule 10D-1 under the Exchange Act (17 CFR 240.10D-1) by the registered national securities exchange or registered national securities association upon which the registrants securities are listed. Not applicable to the registrant.

(a)

(3) Certifications of principal executive officer and principal financial officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 are attached hereto as Exhibit EX-99.CERT.

(a)

(4) Written solicitation to purchase securities under Rule 23c-1 under the Investment Company Act of 1940 sent or given during the period covered by the report by or on behalf of the registrant to 10 or more persons. Not applicable to the registrant.

(a)

(5) Change in the registrants independent public accountant. Provide the information called for by Item 4 of Form 8-K under the Exchange Act (17 CFR 249.308). Unless otherwise specified by Item 4, or related to and necessary for a complete understanding of information not previously disclosed, the information should relate to events occurring during the reporting period. Not applicable.

(b)

Certifications of principal executive officer and principal financial officer pursuant to Section 906 of the Sarbanes-Oxley Act of 2002 are attached hereto as Exhibit EX-99.906CERT.

(c)

Disclosure pursuant to Section 13(r) of the Securities Exchange Act of 1934, as amended, is attached hereto as Exhibit EX-99.IRANNOTICE.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Master Trust


By:		/s/ Mark E. Carver
		Mark E. Carver
		President

Date:		July 7, 2025

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.


By:		/s/ Mark E. Carver
		Mark E. Carver
		President

Date:		July 7, 2025

By:		/s/ Joanne M. Kilkeary
		Joanne M. Kilkeary
		Vice President, Treasurer and Principal Accounting Officer

Date:		July 7, 2025

Master Trust published this content on July 07, 2025, and is solely responsible for the information contained herein. Distributed via SEC EDGAR on July 07, 2025 at 21:09 UTC. If you believe the information included in the content is inaccurate or outdated and requires editing or removal, please contact us at [email protected]

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