Arthur J. Gallagher & Co. (AJG) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-07-01 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: Arthur J. Gallagher & Co. (AJG) CIK: 0000354190 --- Reporting Owner --- Name: Jain Vishal CIK: 0001812516 Role: Officer (VICE PRESIDENT) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-07-01 | Code: M (Exercise of derivative) Shares: +2,162.694 | Price: $229.57 Total Value: $496,489.66 Shares Owned After: 68,903.384 | Ownership: D (Direct) --- Derivative Transactions --- [Transaction #1] Security: Notional Stock Units Date: 2026-07-01 | Code: M (Exercise of derivative) Shares: -2,162.694 | Price: $0.00 Shares Owned After: 9,725.8456 | Ownership: D (Direct) Footnotes: [F1] Each notional stock unit represents a right to receive one share of Gallagher common stock. [F2] The notional stock units become payable in July 2026 and following the reporting person's separation from service with Gallagher. [F2] The notional stock units become payable in July 2026 and following the reporting person's separation from service with Gallagher. --- Holdings --- [Holding #1] Security: Common Stock Ownership: I (Indirect) [Holding #2] Security: Phantom Stock Ownership: D (Direct) Footnotes: [F3] Each share of phantom stock represents a right to receive one share of Gallagher common stock. [F4] 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. [F4] 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. [Holding #3] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F5] One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #4] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F6] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #5] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F6] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [F7] Grant date of 3/12/2020. [Holding #6] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F6] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #7] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F8] Closing price of Gallagher common stock on February 28, 2025. [F6] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #8] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F9] One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #9] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F10] One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. --- Footnotes (Complete Index) --- F1: Each notional stock unit represents a right to receive one share of Gallagher common stock. F10: One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. F2: The notional stock units become payable in July 2026 and following the reporting person's separation from service with Gallagher. F3: Each share of phantom stock represents a right to receive one share of Gallagher common stock. F4: 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. F5: One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. F6: One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. F7: Grant date of 3/12/2020. F8: Closing price of Gallagher common stock on February 28, 2025. F9: One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. --- Signature --- /s/ /s/ Monica Norzagaray, by power of attorney (2026-07-06)