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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(Mark One)

For the quarterly period ended March 31, 2026

or

For the transition period from________________to

Commission File Number: 1-09761

ARTHUR J. GALLAGHER & CO.

(Exact name of registrant as specified in its charter)

2850 Golf Road, Rolling Meadows, Illinois 60008

(Address of principal executive offices) (Zip Code)

(630) 773-3800

(Registrant’s telephone number, including area code)

Not Applicable

(Former name, former address and former fiscal year, if changed since last report)

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15 (d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b‑2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No ☒

The number of outstanding shares of the registrant’s common stock, $1.00 par value, as of March 31, 2026 was approximately 256.9 million.

Information Concerning Forward-Looking Statements

This report contains “forward-looking statements” as that term is defined in the Private Securities Litigation Reform Act of 1995. These statements relate to expectations and future events and may include words such as “anticipate,” “believe,” “estimate,” “expect,” “forecast,” “project,” “intend,” “plan,” “potential,” and other similar terms, and future or conditional tense verbs like “could,” “may,” “might,” “see,” “should,” “will” and “would.” You can also identify forward-looking statements by the fact that they do not relate strictly to historical or current facts.

Forward-looking statements may address topics such as: our future performance, including our future financial and operating results; general economic conditions, including the impact of tariffs, inflation and interest rate fluctuations; market and industry conditions; our acquisition strategy, including expected benefits of our acquisition of AssuredPartners and the duration and costs of integrating acquisitions; our competitive position, cost structure, capital expenditures, debt levels and liquidity; regulatory actions and litigation matters; geopolitical conditions; and other operational, financial and strategic matters.

These statements are subject to risks and uncertainties that could cause actual results to differ materially from historical or anticipated results depending on a variety of factors.

Factors that could impact results include:

• Global economic and geopolitical events, including fluctuations in interest and inflation rates; protectionism such as tariffs; trade disruptions; economic downturn; government shutdowns; and political instability, including global armed conflicts;

• Economic conditions that result in financial difficulties for underwriting enterprises or reduced risk-taking capital capacity, including as a result of large catastrophe losses or enterprise failures, and increased E&O claims;

• Risks that could negatively affect the success of our acquisition strategy, including economic uncertainty affecting sourcing and pricing; industry consolidation and competition for targets; inaccurate assumptions and failure to realize expected benefits; regulatory approval; closing and integration risks; potential impairment charges; and unanticipated liabilities including cybersecurity and compliance risks;

• Risks related to AssuredPartners and other acquisitions larger than our usual tuck-in acquisitions, including integration risks and risks resulting from inaccurate assumptions such as unforeseen liabilities and failure to realize expected benefits;

• Damage to our reputation, including as a result of failing to uphold our culture and the potential for social media to amplify any negative effects;

• Failure to meet our sustainability aspirations, goals and initiatives or to comply with climate-related and other sustainability regulations, heightened scrutiny, including growing backlash against sustainability initiatives, and risks related to “greenwashing” and “greenhushing";

• Failure to apply technology, data analytics and artificial intelligence effectively to drive client value, internal efficiencies and effective controls;

• Risks associated with the use of AI in our business operations, including regulatory, data privacy, cybersecurity, E&O, intellectual property and competition risks;

• Risks related to “AI-washing”;

• Failure to attract and retain experienced and qualified talent, including our senior management team, or adequately plan for succession; increased compensation and benefit costs and restrictions on non-compete agreements;

• A disaster or other significant disruption to business continuity affecting our operations or those of third parties on which we rely (including AI providers), including cybersecurity incidents; natural disasters; and incidents of terrorism and civil unrest;

• Sustained increases in the cost of employee benefits and compensation expense;

• Risks arising from our international operations and changes in international conditions, including political and economic uncertainty; compliance with multi-jurisdictional laws (including anti‑corruption, sanctions, privacy and sustainability); protectionism, and trade restrictions, scrutiny of off-shore operations and global health risks;

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• Risks related to changes in U.S. or foreign tax laws;

• Competitive pressures, including as a result of innovation, in each of our businesses;

• Volatility or declines in premiums or other adverse trends in the insurance industry;

• The higher level of variability inherent in contingent and supplemental revenues versus standard commission revenues;

• Risks particular to our benefit consulting operations, including risks related to recent acquisitions such as Buck and Redington;

• Risks particular to our third-party claims administration operations, including system availability (including RISX‑FACS®, our proprietary risk management information system), wage inflation, staffing shortages, outsourcing trends and client concentration;

• Climate risks, including transition risks and potential disruptions;

• Cyber-attacks or other cybersecurity incidents including data breaches and evolving cybersecurity and data privacy regulations;

• Unfavorable determinations related to contingencies and legal proceedings, including violations or alleged violations of anti-corruption, tax or other laws and the outcome of investigations, regulatory actions or litigation;

• Failure to comply with regulatory requirements, including governance and control requirements, international sanctions, sustainability disclosures and AI-related laws and regulations, and changes in enforcement policies;

• Changes to our financial presentation from new accounting estimates and assumptions;

• Intellectual property risks;

• Risks related to our legacy clean energy investments, including intellectual property, environmental and product liability claims, compliance costs and potential disallowance of previously claimed tax credits;

• The risk that our outstanding debt adversely affects our financial flexibility and related covenant restrictions;

• The risk of credit rating downgrades;

• The risk that we may not be able to receive dividends or other distributions from our subsidiaries, including foreign exchange rates;

• The risk of share ownership dilution when we issue common stock; and

• Volatility of the price of our common stock.

Forward-looking statements are not guarantees of future performance and involve risks and uncertainties. Actual results or outcomes may differ materially from those expressed in forward-looking statements and you should not rely unduly on these statements.

All forward-looking statements are qualified by these cautionary statements and speak only as of the date made. We undertake no obligation to update them except as required by law. Sustainability-related statements may rely on evolving standards and assumptions.

A detailed discussion of the factors that could cause actual results to differ materially from our published expectations is contained under the heading “Risk Factors” in our filings with the Securities and Exchange Commission (SEC), including our most recent Annual Report on Form 10-K, this and subsequent Quarterly Reports on Form 10-Q and any other reports we file with the SEC in the future.

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Arthur J. Gallagher & Co.

Index

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Part I - Financial Information