FORM 4 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
or Section 30(h) of the Investment Company Act of 1940
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 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person *
GALLAGHER THOMAS JOSEPH
(Last) (First) (Middle)
2850 GOLF ROAD
(Street)
ROLLING MEADOWS IL 60008-4002
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
Arthur J. Gallagher & Co. [ AJG ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
President
3. Date of Earliest Transaction (Month/Day/Year)
03/15/2026
4. If Amendment, Date of Original Filed (Month/Day/Year)
 6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 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
Common Stock (restricted) 03/15/2026   A   9,560 (1) A $ 0 9,560 D  
Common Stock (restricted) 03/15/2026   M   9,560 D $ 0 0 D  
Common Stock 03/15/2026   M   9,560 A $ 0 328,251.08 D  
Common Stock 03/15/2026   F   4,068 D $ 207.93 324,183.08 D  
Common Stock               62,295 I By grantor retained annuity trust
Common Stock               96,709 I By Irrevocable Trust
Common Stock               32,428 I By wife
Common Stock               119,175 I By wife as trustee (2) (3)
Common Stock               491.14 I Gallagher 401(k) plan account
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 (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 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 (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (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: 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
Non-qualified Stock Option $ 127.9               (4) 03/16/2028 Common Stock 32,895   32,895 D  
Non-qualified Stock Option $ 86.17               (4) 03/12/2027 Common Stock 31,340   31,340 D  
Non-qualified Stock Option $ 228.2               (5) 03/01/2033 Common Stock 22,219   22,219 D  
Phantom Stock (6)               (7)   (7) Common Stock 20,232.185   20,232.185 D  
Non-qualified Stock Option $ 158.56               (4) 03/15/2029 Common Stock 15,310   15,310 D  
Non-qualified Stock Option $ 243.54               (8) 03/01/2031 Common Stock 15,070   15,070 D  
Non-qualified Stock Option $ 337.74 (9)               (4) 03/01/2032 Common Stock 14,876   14,876 D  
Non-qualified Stock Option $ 177.09               (10) 03/15/2030 Common Stock 12,744   12,744 D  
Notional Stock Units $ 0 (11)               (12)   (12) Common Stock 11,445.7485   11,445.7485 D  
Explanation of Responses:
1. Performance share units (awarded on March 15, 2023) earned and vested as of March 15, 2026.
2. The reporting person disclaims beneficial ownership of these shares, and this report shall not be deemed an admission that the reporting person is the beneficial owner of these shares for purposes of Section 16 or for any other purpose.
3. These shares are held in trusts, for the benefit of the reporting person's children, of which his wife is a trustee.
4. One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
5. One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
6. Each share of phantom stock represents a right to receive one share of Gallagher common stock.
7. These shares represent awards under the Age 62 Plan, a nonqualified deferred compensation plan of the Company, which have been deemed invested in Company common stock at the election of the reporting person. Participants vest in these awards when they attain age 62, or after a one-year period for participants who have attained age 61.
8. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
9. Closing price of Gallagher common stock on February 28, 2025.
10. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
11. Each notional stock unit represents a right to receive one share of Gallagher common stock.
12. Portions of these notional stock units are payable to the reporting person in shares of common stock in July of 2025 and 2026 and following the reporting person's separation from service.
/s/ Monica Norzagaray, by power of attorney 03/17/2026
** Signature of Reporting Person Date
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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