SEC FORM 4

SEC FORM 4SEC Form 4

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).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Bay Walter D.

(Last)

(First)

(Middle)

2850 GOLF ROAD

(Street)

ROLLING MEADOWS

ILLINOIS

60008-4002

(City)

(State)

(Zip)

UNITED STATES

(Country)

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)
	General Counsel

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/31/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	03/31/2026		M		1,415.092	A	$215.95	83,919.092	D
Common Stock	03/31/2026		F		627	D	$215.95	83,292.092⁽¹⁾	D
Common Stock								491.129	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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
Phantom Stock	⁽²⁾	03/31/2026		M			1,415.092	⁽³⁾	⁽³⁾	Common Stock	1,415.092	$0	3,994.734	D
Non-qualified Stock Option	$127.9							⁽⁴⁾	03/16/2028	Common Stock	24,500		24,500	D
Non-qualified Stock Option	$86.17							⁽⁴⁾	03/12/2027	Common Stock	17,630		17,630	D
Non-qualified Stock Option	$228.2							⁽⁵⁾	03/01/2033	Common Stock	16,952		16,952	D
Non-qualified Stock Option	$158.56							⁽⁴⁾	03/15/2029	Common Stock	11,405		11,405	D
Non-qualified Stock Option	$337.74⁽⁶⁾							⁽⁴⁾	03/01/2032	Common Stock	11,350		11,350	D
Non-qualified Stock Option	$243.54							⁽⁷⁾	03/01/2031	Common Stock	10,884		10,884	D
Non-qualified Stock Option	$177.09							⁽⁸⁾	03/15/2030	Common Stock	9,452		9,452	D
Notional Stock Units	$0⁽⁹⁾							⁽¹⁰⁾	⁽¹⁰⁾	Common Stock	5,828.5456		5,828.5456	D

Explanation of Responses:

1. The transactions in this report relate solely to the distribution of vested shares under the Age 62 Plan and the withholding of shares to cover applicable income and employment taxes.

2. Each share of phantom stock represents a right to receive one share of Gallagher common stock.

3. 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 in the year they attain age 62, or after a one-year period for participants who have attained age 61.

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 exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.

6. Closing price of Gallagher common stock on February 28, 2025.

7. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.

8. One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date.

9. Each notional stock unit represents a right to receive one share of Gallagher common stock.

10. The notional stock units become payable following the reporting person's separation from service with Gallagher.

Remarks:

The transactions in this report relate solely to the distribution of vested shares under the Age 62 Plan and the withholding of shares to cover applicable income and employment taxes.

	/s/ Monica Norzagaray, by power of attorney	04/01/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

SEC Form 4 filed by Bay Walter D.