Sec Form 4 Filing - WATSA V PREM ET AL @ Under Armour, Inc. - 2025-12-22

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person WATSA V PREM ET AL 2. Issuer Name and Ticker or Trading Symbol Under Armour, Inc. [ UA] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 95 WELLINGTON STREET WEST SUITE 800 3. Date of Earliest Transaction (MM/DD/YY) 12/22/2025 (Street) TORONTO, A6M5J 2N7 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Class A Common Shares 12/22/2025 P 5,383,513 A $ 4.5285 ( 1 ) 24,691,049 I See Footnote ( 3 ) Class C Common Shares 12/22/2025 P 2,355,641 A $ 4.3562 ( 2 ) 5,599,950 I See Footnote ( 3 ) Class A Common Shares 12/23/2025 P 2,124,452 A $ 4.5443 ( 4 ) 26,815,501 I See Footnote ( 3 ) Class C Common Shares 12/23/2025 P 620,801 A $ 4.3765 ( 5 ) 6,220,751 I See Footnote ( 3 ) Class A Common Shares 12/24/2025 P 875,548 A $ 4.6238 ( 6 ) 27,691,049 I See Footnote ( 3 ) Class C Common Shares 12/24/2025 P 438,333 A $ 4.397 ( 7 ) 6,659,084 I See Footnote ( 3 ) Class A Common Shares 12/26/2025 P 1,000,000 A $ 4.6384 ( 8 ) 28,691,049 I See Footnote ( 3 ) Class C Common Shares 12/26/2025 P 385,850 A $ 4.42 ( 9 ) 7,044,934 I See Footnote ( 3 ) Class A Common Shares 12/29/2025 P 1,763,396 A $ 4.7315 ( 10 ) 30,454,445 I See Footnote ( 3 ) Class C Common Shares 12/29/2025 P 734,430 A $ 4.4776 ( 11 ) 7,779,364 I See Footnote ( 3 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other WATSA V PREM ET AL 95 WELLINGTON STREET WEST SUITE 800 TORONTO, A6M5J 2N7 X FAIRFAX FINANCIAL HOLDINGS LTD/ CAN 95 WELLINGTON STREET WEST SUITE 800 TORONTO, A6M5J 2N7 X Signatures /s/ V. Prem Watsa 12/29/2025 Signature of Reporting Person Date /s/ Peter Clarke, President and Chief Operating Officer, on behalf of Fairfax Financial Holdings Limited 12/29/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents the weighted average price of the Class A Common Shares purchased on December 22, 2025, ranging from a low of $4.4599 to a high of $4.6000 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 2 )Represents the weighted average price of the Class C Common Shares purchased on December 22, 2025, ranging from a low of $4.2850 to a high of $4.4000 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 3 )These securities are held by wholly-owned subsidiaries of Fairfax Financial Holdings Limited. Mr. Watsa is the Chief Executive Officer and controlling person of Fairfax Financial Holdings Limited through certain holding companies he controls, including The Second 810 Holdco Ltd, The Second 1109 Holdco Ltd, The Sixty Two Investment Company Limited and 12002574 Canada Inc. Each of the Reporting Persons disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Exchange Act, except to the extent of its or his pecuniary interest therein, if any. This report shall not be deemed an admission that any of the Reporting Persons is a beneficial owner for the purpose of Section 16 of the Exchange Act, or for any other purpose. ( 4 )Represents the weighted average price of the Class A Common Shares purchased on December 23, 2025, ranging from a low of $4.5150 to a high of $4.5500 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 5 )Represents the weighted average price of the Class C Common Shares purchased on December 23, 2025, ranging from a low of $4.3550 to a high of $4.3900 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 6 )Represents the weighted average price of the Class A Common Shares purchased on December 24, 2025, ranging from a low of $4.5800 to a high of $4.6500 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 7 )Represents the weighted average price of the Class C Common Shares purchased on December 24, 2025, ranging from a low of $4.3600 to a high of $4.4000 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 8 )Represents the weighted average price of the Class A Common Shares purchased on December 26, 2025, ranging from a low of $4.6050 to a high of $4.6700 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 9 )Represents the weighted average price of the Class C Common Shares purchased on December 26, 2025, ranging from a low of $4.3912 to a high of $4.4300 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 10 )Represents the weighted average price of the Class A Common Shares purchased on December 29, 2025, ranging from a low of $4.6500 to a high of $4.7700 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price. ( 11 ) Represents the weighted average price of the Class C Common Shares purchased on December 29, 2025, ranging from a low of $4.4000 to a high of $4.5400 per share. The Reporting Persons undertake, upon request by the staff of the Securities and Exchange Commission, the Issuer or a security holder of the Issuer to provide full information regarding the number of shares purchased at each separate price.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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