AJG Arthur J Gallagher and Company

On November 15, 2022, Arthur J. Gallagher & Co. (the “Company”) entered into an equity distribution agreement (the “Equity Distribution Agreement”) with Morgan Stanley & Co. LLC (“Morgan Stanley”), pursuant to which the Company may offer and sell up to 3,000,000 shares of the Company’s common stock, par value $1.00 per share (the “shares”), from time to time, in “at-the-market” offerings through Morgan Stanley, as sales agent (the “at-the-market program”). Sales of the shares, if any, will be made at prevailing market prices at the time of sale, or as otherwise agreed with Morgan Stanley. Morgan Stanley will receive a commission from the Company that will not exceed, but may be lower than, 1.25% of the gross sales price of all shares sold under the Equity Distribution Agreement. The shares will be issued pursuant to the Company’s shelf registration statement, dated as of March 8, 2021 (Registration No. 333-254015), as supplemented by the prospectus supplement, dated November 15, 2022.

The Company is not obligated to sell, and Morgan Stanley is not obligated to buy or sell, any shares under the Equity Distribution Agreement, and no assurance can be given that the Company will sell any such shares, or, if it does, as to the price or amount of shares that it sells or the dates when such sales will take place. Under the Equity Distribution Agreement, the Company agreed to indemnify Morgan Stanley against certain liabilities, including under the Securities Act of 1933, as amended, or to contribute payments that Morgan Stanley may be required to make because of such liabilities.

The foregoing description of the Equity Distribution Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the agreement. A copy of the Equity Distribution Agreement is attached as Exhibit 1.1 hereto and is incorporated herein by reference. In addition, a copy of the opinion of Gibson, Dunn & Crutcher LLP relating to the validity of the shares that may be sold pursuant to the Equity Distribution Agreement is filed herewith as Exhibit 5.1.

On November 16, 2022, the Company issued a press release announcing the establishment of the at-the-market program and the filing of a Registration Statement on Form S-4 with the Securities and Exchange Commission. A copy of this press release is attached as Exhibit 99.1 hereto.