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: 2026-05-26 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: Arthur J. Gallagher & Co. (AJG) CIK: 0000354190 --- Reporting Owner --- Name: Gallagher Patrick Murphy CIK: 0001929606 Role: Officer (Chief Operating Officer) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-05-26 | Code: G (Gift) Shares: +14,698 | Price: $0.00 Shares Owned After: 98,105.25 | Ownership: I (Indirect) | Nature: By Trust Footnotes: [F1] Shares held in trust for the benefit of the reporting person and immediate family members, of which he and his immediate family members, as applicable, is a trustee. --- Holdings --- [Holding #1] Security: Common Stock Ownership: I (Indirect) Footnotes: [F2] Shares held in trusts, for the benefit of the reporting person's children, of which his wife is sole trustee. [Holding #2] Security: Common Stock Ownership: D (Direct) [Holding #3] Security: Common Stock Ownership: I (Indirect) [Holding #4] Security: Common Stock Ownership: I (Indirect) Footnotes: [F3] Shares held in a revocable trust and an irrevocable trust of which the reporting person's spouse is sole Trustee and as to which he disclaims beneficial ownership [Holding #5] Security: Common Stock Ownership: I (Indirect) Footnotes: [F4] Shares held in trust for the benefit of the reporting person's children, of which he is a trustee. [Holding #6] Security: Common Stock Ownership: I (Indirect) [Holding #7] 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 #8] Security: Phantom Stock Ownership: D (Direct) Footnotes: [F6] Each share of phantom stock represents a right to receive one share of Gallagher common stock. [F7] 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. [F7] 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 #9] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F8] Closing price of Gallagher common stock on February 28, 2025. [F9] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #10] 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. [Holding #11] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F9] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [F11] Grant date of 3/16/2021. [Holding #12] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F9] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [F12] Grant date of 3/12/2020. [Holding #13] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F13] One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [Holding #14] Security: Non-qualified Stock Option Ownership: D (Direct) Footnotes: [F9] One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. [F14] Grant date of 3/15/2022. [Holding #15] Security: Phantom Stock Ownership: D (Direct) Footnotes: [F6] Each share of phantom stock represents a right to receive one share of Gallagher common stock. [F15] These shares represent awards under the Deferred Cash Participation Plan, a nonqualified deferred compensation plan of the Company, which have been deemed invested in Company common stock at the election of the participant. These awards are payable in a lump sum on the six-month anniversary of the reporting person's separation from service. [F15] These shares represent awards under the Deferred Cash Participation Plan, a nonqualified deferred compensation plan of the Company, which have been deemed invested in Company common stock at the election of the participant. These awards are payable in a lump sum on the six-month anniversary of the reporting person's separation from service. [Holding #16] Security: Notional Stock Units Ownership: D (Direct) Footnotes: [F16] Each notional stock unit represents a right to receive one share of Gallagher common stock. [F17] The notional stock units become payable following the reporting person's separation from service with Gallagher. [F18] The notional stock units become payable following the reporting person's separation from service with Gallagher. --- Footnotes (Complete Index) --- F1: Shares held in trust for the benefit of the reporting person and immediate family members, of which he and his immediate family members, as applicable, is a trustee. F10: One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. F11: Grant date of 3/16/2021. F12: Grant date of 3/12/2020. F13: One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. F14: Grant date of 3/15/2022. F15: These shares represent awards under the Deferred Cash Participation Plan, a nonqualified deferred compensation plan of the Company, which have been deemed invested in Company common stock at the election of the participant. These awards are payable in a lump sum on the six-month anniversary of the reporting person's separation from service. F16: Each notional stock unit represents a right to receive one share of Gallagher common stock. F17: The notional stock units become payable following the reporting person's separation from service with Gallagher. F18: The notional stock units become payable following the reporting person's separation from service with Gallagher. F2: Shares held in trusts, for the benefit of the reporting person's children, of which his wife is sole trustee. F3: Shares held in a revocable trust and an irrevocable trust of which the reporting person's spouse is sole Trustee and as to which he disclaims beneficial ownership F4: Shares held in trust for the benefit of the reporting person's children, of which he is a trustee. F5: One-third of this stock option becomes exercisable on each of the 3rd, 4th, and 5th anniversaries of the grant date. F6: Each share of phantom stock represents a right to receive one share of Gallagher common stock. F7: 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. F8: Closing price of Gallagher common stock on February 28, 2025. F9: One-third of this stock option becomes exerciseable on each of the 3rd, 4th, and 5th anniversaries of the grant date. --- Signature --- /s/ /s/ Monica Norzagaray, by power of attorney (2026-05-28)