Master Portfolio Trust

04/28/2026 | Press release | Distributed by Public on 04/28/2026 05:21

Semi-Annual Report by Investment Company (Form N-CSRS)

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED

MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number 811-10407

Master Portfolio Trust

(Exact name of registrant as specified in charter)

One Madison Avenue, 17th Floor, New York, NY 10010

(Address of principal executive offices) (Zip code)

Marc A. De Oliveira

Franklin Templeton

100 First Stamford Place

Stamford, CT 06902

(Name and address of agent for service)

Registrant's telephone number, including area code: 877-6LM-FUND/656-3863

Date of fiscal year end: August 31

Date of reporting period: February 28, 2026

ITEM 1. REPORT TO STOCKHOLDERS.

(a) The Report to Shareholders is filed herewith

U.S. Treasury Obligations Portfolio
Semi-Annual Shareholder Report | February 28, 2026
This semi-annual shareholder report contains important information about U.S. Treasury Obligations Portfolio for the period September 1, 2025, to February 28, 2026.
You can find additional information about the Fund at https://www.franklintempleton.com/regulatory-masterfunds-documents. You can also request this information by contacting us at 1-800-625-4554, or 1-203-703-6002.
WHAT WERE THE FUND COSTS FOR THE LAST SIX MONTHS? (based on a hypothetical $10,000 investment)
Fund Name
Costs of a $10,000 investment
Costs paid as a percentage of a $10,000 investment*,†
U.S. Treasury Obligations Portfolio
$2
0.03%
* Expense amounts may be voluntarily waived and/or reimbursed from time to time.
† Annualized.
KEY FUND STATISTICS (as of February 28, 2026)
Total Net Assets
$599,613,569
Total Number of Portfolio Holdings
27
WHAT DID THE FUND INVEST IN? (as of February 28, 2026)
Portfolio Composition (% of Total Investments)
WHERE CAN I FIND ADDITIONAL INFORMATION ABOUT THE FUND?
Additional information is available on https://www.franklintempleton.com/regulatory-masterfunds-documents, including its:
• proxy voting information • financial information • holdings • tax information
U.S. Treasury Obligations Portfolio PAGE 1 98069-SHTSR-0426

(b) Not applicable

ITEM 2. CODE OF ETHICS.

Not applicable.

ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT.

Not applicable.

ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES.

Not applicable.

ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS.

Not applicable.

ITEM 6. SCHEDULE OF INVESTMENTS.
(a) Please see schedule of investments contained in the Financial Statements and Financial Highlights included under Item 7 of this Form N-CSR.
(b) Not applicable.
ITEM 7. FINANCIAL STATEMENTS AND FINANCIAL HIGHLIGHTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.
Schedule of Investments (unaudited) February 28, 2026
 U.S. Treasury Obligations Portfolio
(Percentages shown based on Portfolio net assets)  
Security
Rate
Maturity
Date
Face
Amount
Value
Short-Term Investments - 91.9%
U.S. Treasury Bills - 33.8%
U.S. Treasury Bills
2.551%
3/3/26
$7,000,000
$6,998,551
  (a)
U.S. Treasury Bills
2.989%
3/5/26
10,000,000
9,995,967
  (a)
U.S. Treasury Bills
3.481%
3/12/26
21,500,000
21,475,828
  (a)
U.S. Treasury Bills
3.567%
3/17/26
15,000,000
14,975,533
  (a)
U.S. Treasury Bills
3.559%
3/19/26
10,000,000
9,981,810
  (a)
U.S. Treasury Bills
3.609%
3/24/26
30,000,000
29,930,146
  (a)
U.S. Treasury Bills
3.599%
3/26/26
10,000,000
9,974,847
  (a)
U.S. Treasury Bills
3.744%
3/31/26
10,000,000
9,968,833
  (a)
U.S. Treasury Bills
3.650%
4/2/26
10,000,000
9,967,644
  (a)
U.S. Treasury Bills
3.728%
4/9/26
5,000,000
4,979,985
  (a)
U.S. Treasury Bills
3.672%
4/14/26
10,000,000
9,955,633
  (a)
U.S. Treasury Bills
3.614%
4/16/26
15,000,000
14,931,575
  (a)
U.S. Treasury Bills
3.685%
4/21/26
5,000,000
4,974,288
  (a)
U.S. Treasury Bills
3.647%
4/23/26
10,000,000
9,947,147
  (a)
U.S. Treasury Bills
3.565%
4/28/26
15,000,000
14,915,300
  (a)
U.S. Treasury Bills
3.674%
5/7/26
10,000,000
9,933,000
  (a)
U.S. Treasury Bills
3.684%
5/14/26
10,000,000
9,925,946
  (a)
Total U.S. Treasury Bills
202,832,033
U.S. Treasury Notes - 8.0%
U.S. Treasury Notes
0.750%
3/31/26
5,000,000
4,986,200
  
U.S. Treasury Notes (3 mo. U.S. Treasury Money
Market Yield + 0.150%)
3.793%
4/30/26
43,000,000
43,007,776
  (b)
Total U.S. Treasury Notes
47,993,976
Repurchase Agreements - 50.1%
Canadian Imperial Bank of Commerce tri-party
repurchase agreement dated 2/27/26; Proceeds at
maturity - $20,006,100; (Fully collateralized by
U.S. government obligations, 0.125% to 4.500%
due 3/31/26 to 2/15/54; Market value -
$20,406,231)
3.660%
3/2/26
20,000,000
20,000,000
  
Credit Agricole SA tri-party repurchase agreement
dated 2/27/26; Proceeds at maturity -
$50,015,250; (Fully collateralized by U.S.
government obligations, 0.000% to 4.375% due
10/29/26 to 8/15/53; Market value - $51,000,026)
3.660%
3/2/26
50,000,000
50,000,000
  
See Notes to Financial Statements.
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
0
Schedule of Investments (unaudited) (cont'd) February 28, 2026
 U.S. Treasury Obligations Portfolio
(Percentages shown based on Portfolio net assets)
Security
Rate
Maturity
Date
Face
Amount
Value
Repurchase Agreements - continued
Fixed Income Clearing Corp. tri-party repurchase
agreement dated 2/27/26; Proceeds at maturity -
$10,003,050; (Fully collateralized by U.S.
government obligations, 3.500% due 1/31/28;
Market value - $10,200,072)
3.660%
3/2/26
$10,000,000
$10,000,000
  
Fixed Income Clearing Corp. tri-party repurchase
agreement dated 2/27/26; Proceeds at maturity -
$95,029,054; (Fully collateralized by U.S.
government obligations, 2.500% due 3/31/27;
Market value - $96,900,058)
3.670%
3/2/26
95,000,000
95,000,000
  
HSBC Bank USA tri-party repurchase agreement
dated 2/27/26; Proceeds at maturity -
$10,003,033; (Fully collateralized by U.S.
government obligations, 1.375% due 8/15/50;
Market value - $10,203,127)
3.640%
3/2/26
10,000,000
10,000,000
  
JPMorgan Securities LLC tri-party repurchase
agreement dated 2/27/26; Proceeds at maturity -
$5,001,525; (Fully collateralized by U.S. government
obligations, 0.125% to 4.625% due 4/30/28 to
4/30/31; Market value - $5,101,569)
3.660%
3/2/26
5,000,000
5,000,000
  
Societe Generale SA tri-party repurchase
agreement dated 2/27/26; Proceeds at maturity -
$50,015,250; (Fully collateralized by U.S.
government obligations, 4.750% due 8/15/55;
Market value - $51,000,005)
3.660%
3/2/26
50,000,000
50,000,000
  
TD Securities LLC tri-party repurchase agreement
dated 2/27/26; Proceeds at maturity -
$60,018,350; (Fully collateralized by U.S.
government obligations, 1.500% to 3.875% due
2/15/30 to 8/15/34; Market value - $61,200,086)
3.670%
3/2/26
60,000,000
60,000,000
  
Total Repurchase Agreements
300,000,000
Total Investments - 91.9% (Cost - $550,826,009#)
550,826,009
Other Assets in Excess of Liabilities - 8.1%
48,787,560
Total Net Assets - 100.0%
$599,613,569
 
#
Aggregate cost for federal income tax purposes is substantially the same.
(a)
Rate shown represents yield-to-maturity.
(b)
Variable rate security. Interest rate disclosed is as of the most recent information available. 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 their
description above.
See Notes to Financial Statements.
1
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
Statement of Assets and Liabilities (unaudited) February 28, 2026
 
Assets:
Investments, at value
$250,826,009
Repurchase agreements, at value
300,000,000
Cash
63,544,915
Interest receivable
219,132
Prepaid expenses
17,300
Total Assets
614,607,356
Liabilities:
Payable for securities purchased
14,915,300
Trustees' fees payable
626
Accrued expenses
77,861
Total Liabilities
14,993,787
Total Net Assets
$599,613,569
Represented by:
Paid-in capital
$599,613,569
See Notes to Financial Statements.
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
2
Statement of Operations (unaudited) For the Six Months Ended February 28, 2026
 
Investment Income:
Interest
$11,454,783
Expenses:
Fund accounting fees
31,461
Audit and tax fees
19,556
Trustees' fees
9,096
Interest expense
1,974
Custody fees
747
Miscellaneous expenses
33,755
Total Expenses
96,589
Net Investment Income
11,358,194
Net Realized Gain on Investments
96,068
Increase in Net Assets From Operations
$11,454,262
See Notes to Financial Statements.
3
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
Statements of Changes in Net Assets
 
For the Six Months Ended February 28, 2026 (unaudited)
and the Year Ended August 31, 2025
2026
2025
Operations:
Net investment income
$11,358,194
$24,723,631
Net realized gain
96,068
1,332
Increase in Net Assets From Operations
11,454,262
24,724,963
Capital Transactions:
Proceeds from contributions
1,569,808,318
1,612,100,834
Value of withdrawals
(1,607,267,044
)
(1,466,189,673
)
Increase (Decrease) in Net Assets From Capital
Transactions
(37,458,726
)
145,911,161
Increase (Decrease) in Net Assets
(26,004,464
)
170,636,124
Net Assets:
Beginning of period
625,618,033
454,981,909
End of period
$599,613,569
$625,618,033
See Notes to Financial Statements.
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
4
Financial Highlights
 
For the years ended August 31, unless otherwise noted:
20261
2025
2024
2023
2022
2021
Net assets, end of period (millions)
$600
$626
$455
$538
$401
$417
Total return2
1.96
%
4.60
%
5.48
%
4.49
%
0.54
%
0.07
%
Ratios to average net assets:
Gross expenses
0.03
%3
0.04
%
0.04
%
0.04
%
0.04
%
0.03
%
Net expenses4
0.03
3
0.04
0.04
0.04
0.04
0.03
Net investment income
3.92
3
4.47
5.34
4.45
0.53
0.06
 
1
For the six months ended February 28, 2026 (unaudited).
2
Performance figures may reflect compensating balance arrangements, fee waivers and/or expense reimbursements.
In the absence of compensating balance arrangements, fee waivers and/or expense reimbursements, the total
return would have been lower. Past performance is no guarantee of future results. Total returns for periods of less
than one year are not annualized.
3
Annualized.
4
The investment manager has voluntarily undertaken to limit Portfolio expenses. Such expense limitations may
fluctuate daily and are voluntary and temporary and may be terminated by the investment manager at any time
without notice.
See Notes to Financial Statements.
5
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
Notes to Financial Statements (unaudited)
1. Organization and significant accounting policies
U.S. Treasury Obligations Portfolio (the "Portfolio") is a separate diversified investment series of Master Portfolio Trust (the "Trust"). The Trust, a Maryland statutory trust, is registered under the Investment Company Act of 1940, as amended (the "1940 Act"), as an open-end management investment company. The Declaration of Trust permits the Board of Trustees (the "Board") to issue beneficial interests in the Portfolio. At February 28, 2026, all investors in the Portfolio were funds advised or administered by the investment manager of the Portfolio and/or its affiliates.
The Portfolio follows the accounting and reporting guidance in Financial Accounting Standards Board ("FASB") Accounting Standards Codification Topic 946, Financial Services - Investment Companies ("ASC 946"). The following are significant accounting policies consistently followed by the Portfolio and are in conformity with U.S. generally accepted accounting principles ("GAAP"), including, but not limited to, ASC 946. Estimates and assumptions are required to be made regarding assets, liabilities and changes in net assets resulting from operations when financial statements are prepared. Changes in the economic environment, financial markets and any other parameters used in determining these estimates could cause actual results to differ. Subsequent events have been evaluated through the date the financial statements were issued.
(a) Investment valuation. In accordance with Rule 2a-7 under the 1940 Act, money market instruments are valued at amortized cost, which approximates market value. This method involves valuing portfolio securities at their cost and thereafter assuming a constant amortization to maturity of any discount or premium. The Portfolio's use of amortized cost is subject to its compliance with certain conditions as specified by Rule 2a-7 under the 1940 Act.
Pursuant to policies adopted by the Board, the Portfolio's manager has been designated as the valuation designee and is responsible for the oversight of the daily valuation process. The Portfolio's manager is assisted by the Global Fund Valuation Committee (the "Valuation Committee"). The Valuation Committee is responsible for making fair value determinations, evaluating the effectiveness of the Portfolio's pricing policies, and reporting to the Board.
The Portfolio uses valuation techniques to measure fair value that are consistent with the market approach and/or income approach, depending on the type of security and the particular circumstance. The market approach uses prices and other relevant information generated by market transactions involving identical or comparable securities. The income approach uses valuation techniques to discount estimated future cash flows to present value.
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
6
Notes to Financial Statements (unaudited) (cont'd)
GAAP establishes a disclosure hierarchy that categorizes the inputs to valuation techniques used to value assets and liabilities at measurement date. These inputs are summarized in the three broad levels listed below:
•
Level 1 - unadjusted quoted prices in active markets for identical investments
•
Level 2 - other significant observable inputs (including quoted prices for similar investments, interest rates, prepayment speeds, credit risk, etc.)
•
Level 3 - significant unobservable inputs (including the Portfolio's own assumptions in determining the fair value of investments)
The inputs or methodologies used to value securities are not necessarily an indication of the risk associated with investing in those securities.
The following is a summary of the inputs used in valuing the Portfolio's assets carried at fair value:
 
ASSETS
Description
Quoted Prices
(Level 1)
Other Significant
Observable Inputs
(Level 2)
Significant
Unobservable
Inputs
(Level 3)
Total
Short-Term Investments†
-
$550,826,009
-
$550,826,009
 
†
See Schedule of Investments for additional detailed categorizations.
(b) Repurchase agreements. The Portfolio may enter into repurchase agreements with institutions that its subadviser has determined are creditworthy. Each repurchase agreement is recorded at cost. Under the terms of a typical repurchase agreement, the Portfolio acquires a debt security subject to an obligation of the seller to repurchase, and of the Portfolio to resell, the security at an agreed-upon price and time, thereby determining the yield during the Portfolio's holding period. When entering into repurchase agreements, it is the Portfolio's policy that its custodian or a third party custodian, acting on the Portfolio's behalf, take possession of the underlying collateral securities, the market value of which, at all times, at least equals the principal amount of the repurchase transaction, including accrued interest. To the extent that any repurchase transaction maturity exceeds one business day, the value of the collateral is marked-to-market and measured against the value of the agreement in an effort to ensure the adequacy of the collateral. If the counterparty defaults, the Portfolio generally has the right to use the collateral to satisfy the terms of the repurchase transaction. However, if the market value of the collateral declines during the period in which the Portfolio seeks to assert its rights or if bankruptcy proceedings are commenced with respect to the seller of the security, realization of the collateral by the Portfolio may be delayed or limited.
(c) Interest income and expenses. Interest income (including interest income from payment-in-kind securities) consists of interest accrued and discount earned (including both
7
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
original issue and market discount adjusted for amortization of premium) on the investments of the Portfolio. Expenses of the Portfolio are accrued daily. The Portfolio bears all costs of its operations other than expenses specifically assumed by the investment manager.
(d) Method of allocation. Net investment income of the Portfolio is allocated pro rata, based on respective ownership interests, among the Fund and other investors in the Portfolio (the "Holders") at the time of such determination. Gross realized gains and/or losses of the Portfolio are allocated to the Holders in a manner such that the net asset values per share of each Holder, after each such allocation, is closer to the total of all Holders' net asset values divided by the aggregate number of shares outstanding for all Holders.
(e) Income taxes. The Portfolio is classified as a partnership for federal income tax purposes. As such, each investor in the Portfolio is treated as owner of its proportionate share of the net assets, income, expenses and realized gains and losses of the Portfolio. Therefore, no federal income tax provision is required. It is intended that the Portfolio's assets will be managed so an investor in the Portfolio can satisfy the requirements of Subchapter M of the Internal Revenue Code.
Management has analyzed the Portfolio's tax positions taken on income tax returns for all open tax years and has concluded that as of August 31, 2025, no provision for income tax is required in the Portfolio's financial statements. The Portfolio's federal and state income tax returns for the prior three fiscal years are subject to examination by the Internal Revenue Service and state departments of revenue.
(f) Other. Purchases, maturities and sales of money market instruments are accounted for on the date of the transaction. Realized gains and losses are calculated on the identified cost basis.
2. Investment management agreement and other transactions with affiliates
Franklin Templeton Fund Adviser, LLC ("FTFA") is the Portfolio's investment manager and Western Asset Management Company, LLC ("Western Asset") is the Portfolio's subadviser. FTFA and Western Asset are indirect, wholly-owned subsidiaries of Franklin Resources, Inc. ("Franklin Resources").
Under the investment management agreement, the Portfolio does not pay an investment management fee.
Expense amounts may be voluntarily waived and/or reimbursed from time to time.
FTFA is permitted to recapture amounts waived and/or reimbursed to the Portfolio during the same fiscal year under certain circumstances.
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
8
Notes to Financial Statements (unaudited) (cont'd)
All officers and one Trustee of the Trust are employees of Franklin Resources or its affiliates and do not receive compensation from the Trust.
3. Derivative instruments and hedging activities
During the six months ended February 28, 2026, the Portfolio did not invest in derivative instruments.
4. Operating segments
The Portfolio operates as a single operating segment, which is an investment portfolio. A management group assigned to the Portfolio within the Portfolio's investment manager serves as the Chief Operating Decision Maker ("CODM") and is responsible for evaluating the Portfolio's operating results and allocating resources in accordance with the Portfolio's investment strategy. Internal reporting provided to the CODM aligns with the accounting policies and measurement principles used in the financial statements.
For information regarding segment assets, segment profit or loss, and significant expenses, refer to the Statement of Assets and Liabilities and the Statement of Operations, along with the related Notes to Financial Statements. The Portfolio's Schedule of Investments provides details of the Portfolio's investments that generate returns such as interest, dividends, and realized and unrealized gains or losses. Performance metrics, including expense ratios, are disclosed in the Financial Highlights.
9
U.S. Treasury Obligations Portfolio 2026 Semi-Annual Report
 
Changes in and Disagreements with Accountants
For the period covered by this report
Not applicable.
Results of Meeting(s) of Shareholders
For the period covered by this report
Not applicable.
Remuneration Paid to Directors, Officers and Others
For the period covered by this report
Refer to the financial statements included herein.
U.S. Treasury Obligations Portfolio
10
ITEM 8. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.

The information is disclosed as part of the Financial Statements included in Item 7 of this Form N-CSR.

ITEM 9. PROXY DISCLOSURES FOR OPEN-END MANAGEMENT INVESTMENT COMPANIES.

The information is disclosed as part of the Financial Statements included in Item 7 of this Form N-CSR.

ITEM 10. REMUNERATION PAID TO DIRECTORS, OFFICERS, AND OTHERS OF OPEN-END MANAGEMENT INVESTMENT COMPANIES.

The information is disclosed as part of the Financial Statements included in Item 7 of this Form N-CSR.

ITEM 11. STATEMENT REGARDING BASIS FOR APPROVAL OF INVESTMENT ADVISORY CONTRACT.

The information is disclosed as part of the Financial Statements included in Item 7 of this Form N-CSR, as applicable.

ITEM 12. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable.

ITEM 13. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable.

ITEM 14. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS.

Not applicable.

ITEM 15. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS.

There have been no changes to the procedures by which shareholders may recommend nominees to the Registrant's Board of Trustees that would require disclosure herein.

ITEM 16. CONTROLS AND PROCEDURES.
(a) The Registrant's principal executive officer and principal financial officer have concluded that the Registrant's disclosure controls and procedures (as defined in Rule 30a- 3(c) under the Investment Company Act of 1940, as amended (the "1940 Act")) are effective as of a date within 90 days of the filing date of this report that includes the disclosure required by this paragraph, based on their evaluation of the disclosure controls and procedures required by Rule 30a-3(b) under the 1940 Act and 15d-15(b) under the Securities Exchange Act of 1934.
(b) There were no changes in the Registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the 1940 Act) that occurred during the period covered by this report that have materially affected or are likely to materially affect the Registrant's internal control over financial reporting.
ITEM 17. DISCLOSURE OF SECURITIES LENDING ACTIVITIES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

Not applicable.

ITEM 18. RECOVERY OF ERRONEOUSLY AWARDED COMPENSATION.
(a) Not applicable.
(b) Not applicable.
ITEM 19. EXHIBITS.

(a) (1) Not applicable.

Exhibit 99.CODE ETH

Exhibit 99.CERT

Exhibit 99.906CERT

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, there unto duly authorized.

Master Portfolio Trust

By: /s/ Jane Trust
Jane Trust
Principal Executive Officer
Date: April 27, 2026

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/ Jane Trust
Jane Trust
Principal Executive Officer
Date: April 27, 2026
By: /s/ Christopher Berarducci
Christopher Berarducci
Principal Financial Officer
Date: April 27, 2026
Master Portfolio Trust published this content on April 28, 2026, and is solely responsible for the information contained herein. Distributed via EDGAR on April 28, 2026 at 11:22 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]