FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES 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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(Print or Type Responses)

1. Name and Address of Reporting Person * Jain Vishal 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) VICE PRESIDENT (Last) (First) (Middle) 2850 GOLF ROAD 3. Date of Earliest Transaction (Month/Day/Year) 07/01/2026 (Street) ROLLING MEADOWS, IL 60008 4. If Amendment, Date 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 (City) (State) (Zip) 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 07/01/2026 M 2,162.694 A $229.57 68,903.384 D Common Stock 491.113 I Gallagher 401(k) plan account

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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 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
Notional Stock Units	$ 0 (1)	07/01/2026		M			2,162.694	(2)	(2)	Common Stock	2,162.694	$ 0	9,725.8456	D
Phantom Stock	(3)							(4)	(4)	Common Stock	39,710.185		39,710.185	D
Non-qualified Stock Option	$228.2							(5)	03/01/2033	Common Stock	14,319		14,319	D
Non-qualified Stock Option	$127.9							(6)	03/16/2028	Common Stock	13,580		13,580	D
Non-qualified Stock Option	$86.17							(6)(7)	03/12/2027	Common Stock	10,450		10,450	D
Non-qualified Stock Option	$158.56							(6)	03/15/2029	Common Stock	9,950		9,950	D
Non-qualified Stock Option	$337.74(8)							(6)	03/01/2032	Common Stock	9,587		9,587	D
Non-qualified Stock Option	$243.54							(9)	03/01/2031	Common Stock	8,707		8,707	D
Non-qualified Stock Option	$177.09							(10)	03/15/2030	Common Stock	8,284		8,284	D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Jain Vishal 2850 GOLF ROAD ROLLING MEADOWS, IL 60008			VICE PRESIDENT

Signatures

/s/ Monica Norzagaray, by power of attorney		07/06/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	Each notional stock unit represents a right to receive one share of Gallagher common stock.
(2)	The notional stock units become payable in July 2026 and following the reporting person's separation from service with Gallagher.
(3)	Each share of phantom stock represents a right to receive one share of Gallagher common stock.
(4)	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.
(5)	One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
(6)	One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
(7)	Grant date of 3/12/2020.
(8)	Closing price of Gallagher common stock on February 28, 2025.
(9)	One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
(10)	One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.
Remarks: This report discloses the distribution of notional stock units (representing compensation previously deferred by the reporting person in the Arthur J. Gallagher & Co. Supplemental Savings and Thrift Plan) in the form of Gallagher common stock. The timing of this distribution in July 2026 is in accordance with the terms of the Supplemental Savings and Thrift Plan and the reporting person's election at the time of deferral.

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