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Item 1A. Risk Factors.

Risk Factor Summary

Risks Relating to our Business Generally

•Global economic and geopolitical events, such as fluctuations in interest and inflation rates; geo-economic fragmentation and protectionism; a recession or economic downturn; a U.S. government shutdown or political violence; and instability, including as a result of armed conflicts in Ukraine, the Middle East, Latin America and the Caribbean could adversely affect our results of operations and financial condition.

•Economic conditions that result in financial difficulties for underwriting enterprises or lead to reduced risk-taking capital capacity could adversely affect our results of operations and financial condition.

•We have historically acquired large numbers of insurance brokers, benefit consulting firms and, to a lesser extent, third party claims administration and risk management firms. We may not be able to continue such an acquisition strategy in the future and there are risks associated with such acquisitions, which could adversely affect our growth and results of operations.

•Damage to our reputation and culture could have a material adverse effect on our business.

•Our sustainability aspirations, goals and initiatives, and our public statements and disclosures regarding them, expose us to numerous risks.

•If we are unable to apply technology, data analytics and AI effectively in driving value for our clients through technology-based solutions or gain internal efficiencies and effective internal controls through the application of technology and related tools, our operating results, client relationships, organic and inorganic growth and compliance programs could be adversely affected.

•We are subject to risks associated with AI.

•Our success depends, in part, on our ability to attract and retain qualified talent, including our senior management team.

•Business disruptions could have a material adverse effect on our operations, damage our reputation and impact client relationships.

•Our business or reputation could be harmed by our reliance on third-party providers.

•Sustained increases in compensation expense and the cost of employee benefits could reduce our profitability.

•Our substantial operations outside the U.S. expose us to risks different than those we face in the U.S.

•Changes in tax laws could adversely affect us.

•We face significant competitive pressures in each of our businesses.

•Volatility or declines in premiums or other adverse trends in the insurance industry may seriously undermine our profitability.

•Contingent and supplemental revenues we receive from underwriting enterprises are less predictable than standard commission revenues, and any decrease in the amount of these forms of revenue could adversely affect our results of operations.

•We face a variety of risks in our benefit consulting operations distinct from those we face in our insurance brokerage operations.

•We face a variety of risks in our third-party claims administration operations that are distinct from those we face in our brokerage and benefit consulting operations.

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Regulatory, Legal and Accounting Risks

•Improper disclosure of confidential, personal or proprietary information and cybersecurity attacks or other security breach of our information systems, or those of third-party vendors we rely on, could result in regulatory scrutiny, legal liability or reputational harm, and could adversely affect our business, financial condition and reputation.

•We are subject to a number of contingencies and legal proceedings which, if determined unfavorably to us, would adversely affect our financial results.

•Changes in data privacy and protection laws and regulations, or any failure to comply with such laws and regulations, could adversely affect our business and financial results.

•We could be adversely affected by violations or alleged violations of laws that impose requirements for the conduct of our overseas operations, including the FCPA, the U.K. Bribery Act or other anti-corruption laws, sanctions laws, and FATCA.

•We are subject to regulation worldwide. If we fail to comply with regulatory requirements or if regulations change in a way that adversely affects our operations, we may not be able to conduct our business, or we may be less profitable.

•Changes in our accounting estimates and assumptions could negatively affect our financial position and operating results.

•Limited protection of our intellectual property could harm our business and our ability to compete effectively, and we face the risk that our services or products may infringe upon the intellectual property rights of others.

Risks Relating to our Investments, Debt and Common Stock

•Our clean energy investments are subject to various risks and uncertainties.

•The IRC Section 45 operations in which we have invested and the by-products from such operations may result in environmental and product liability claims and environmental compliance costs.

•We have debt outstanding that could adversely affect our financial flexibility and subjects us to restrictions and limitations that could significantly impact our ability to operate our business.

•Credit rating downgrades would increase our financing costs and could subject us to operational risk.

•We are a holding company and, therefore, may not be able to receive dividends or other distributions in needed amounts from our subsidiaries.

•Future sales or other dilution of our equity could adversely affect the market price of our common stock.

Risks Relating to our Business Generally

Global economic conditions and geopolitical events may impact the countries, regions or industries in which we operate and adversely affect our business results of operations and financial condition.

Global economic and geopolitical events, including fluctuations in interest, inflation and exchange rates, geo-economic fragmentation and protectionism resulting in greater restrictions on international trade and market uncertainty, tariffs, trade wars and other governmental actions affecting the flow of goods, services or currency, military actions and war, including between Russia and Ukraine, the Middle East, Latin America and the Caribbean, political crises like U.S. governmental shutdowns, and political violence and instability worldwide could also weigh negatively on the economy.

A recession or decline in economic activity, for these and any other reasons, could adversely impact us in future periods. For example, our clients might reduce the amount of insurance coverage, reinsurance coverage, consulting services or claims administration services they purchase due to reductions in headcount, payroll, or replacement and asset values, among other factors. Whether these reductions are caused by an overall economic downturn or declines in certain countries, regions and industries in which we operate, our commission and fee revenues, consulting revenues, or revenues

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from managing third-party insurance claims could be adversely impacted. Some of our clients may also experience liquidity problems or other financial difficulties due to tightening credit markets or lower levels of economic activity. If our clients file for bankruptcy, liquidate their operations, consolidate or are generally unable to meet their obligations, our revenues, ability to collect receivables and liquidity could be adversely impacted, which could have an adverse effect on our results of operations and financial condition.

While lower interest rates benefit us by reducing our cost of borrowing, they also reduce investment earnings on our cash, revenue from our premium financing operations and short-term investments of fiduciary and operating funds. In addition, lower levels of inflation may reduce our revenue growth by slowing the increase in insurable asset values.

Uncertain economic conditions have created volatility in the U.S. and other markets where we operate. A rise in the cost of labor or cost of capital, among other things, could negatively impact our operating and general and administrative expenses. We have no or limited control over such developments. If our costs grow significantly, our margins and results of operations may be materially and adversely impacted and we may not be able to achieve our strategic and financial objectives. Further, a tightening of credit or capital markets could negatively impact our business, financial condition and liquidity, including our ability to continue to access preferred sources of liquidity when needed and under similar terms, which may increase our capital costs. We could also experience losses on holdings of cash and investments due to failures of financial institutions and other counterparties. Thus, a deterioration in macroeconomic conditions could adversely affect our business, results of operations or financial condition.

Economic conditions that result in financial difficulties for underwriting enterprises or lead to reduced risk-taking capital capacity could adversely affect our results of operations and financial condition.

We have a significant amount of receivables from certain of the underwriting enterprises with which we place insurance and reinsurance. If those companies experience liquidity problems or other financial difficulties, we could encounter delays or defaults in payments owed to us, which could have a significant adverse impact on our consolidated financial condition and results of operations. The failure of an underwriting enterprise with which we place business could result in E&O claims against us by our clients. Further, the failure of E&O underwriting enterprises could make the E&O insurance we rely upon cost prohibitive or unavailable. Underwriting enterprises are also clients of our reinsurance and third-party claims administration operations and, as such, any of the negative developments for underwriting enterprises referred to above could also reduce our commission and fee revenues from such clients. Any of these developments could adversely affect our results of operations and financial condition. In addition, if underwriting enterprises merge, fail, or withdraw from offering certain lines of coverage, for example, because of large payouts related to natural or man-made disasters, climate or weather events, or other emerging risk areas, overall risk-taking capital capacity could be negatively affected, which could reduce our ability to place certain lines of coverage, reduce demand from the insurance company clients of our reinsurance and third-party claims administration operations and, as a result, reduce our revenues and profitability.

We have historically acquired large numbers of insurance brokers, benefit consulting firms and, to a lesser extent, third party claims administration and risk management firms. We may not be able to continue such acquisition strategy in the future and there are risks associated with such acquisitions, which could adversely affect our growth and results of operations.

Our acquisition program has been an important part of our historical growth, particularly in our brokerage segment, and we believe that similar acquisition activity will be important to maintaining comparable growth in the future. Failure to successfully identify and complete acquisitions would likely result in slower growth. Continuing consolidation in our industry and a high level of interest in acquiring insurance brokers on the part of private equity firms, private equity-backed consolidators and newly public insurance brokers has, in some cases, made, and could in the future make, appropriate acquisition targets more difficult to identify and more expensive. Even if we are able to identify appropriate acquisition targets, we may not have sufficient capital to fund acquisitions, be able to execute transactions on favorable terms or integrate targets in a manner that allows us to realize the benefits we have historically experienced from acquisitions. When regulatory approval of acquisitions is required, our ability to complete acquisitions may be limited by an ongoing regulatory review or other issues with the relevant regulator. Our ability to finance and integrate acquisitions may also decrease if we complete a greater number of larger acquisitions than we have historically. See the paragraph below regarding larger acquisitions. See also Note 3 to our 2025 consolidated financial statements for information regarding the size of transactions in the reporting period.

Post-acquisition risks include poor cultural fit and risks relating to retention of personnel, retention of clients, entry into unfamiliar or complex markets or lines of business, contingencies or liabilities not covered by or in excess of escrowed or indemnified amounts (such as those arising from unlawful sales practices and violations of sanctions laws or anti-corruption laws including the FCPA and U.K. Bribery Act), risks relating to ensuring compliance with licensing and regulatory requirements, tax and accounting issues, the risk that an acquisition distracts management and personnel from our existing business, and integration difficulties relating to accounting, information technology (which we refer to as IT),

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pay equity, or human resources, some or all of which could have an adverse effect on our results of operations and growth. The failure of acquisition targets to achieve anticipated revenue and earnings levels could result in goodwill impairment charges. Additionally, through our acquisitions, we may enter new lines of business or offer new services within existing lines of business. For example, our acquisitions of Woodruff Sawyer and Caytons Law added legal consulting services related to directors' and officers’ liability insurance and a U.K.-based claims and legal solutions firm. These new businesses may pose additional risks or increased regulatory burden.

Integration efforts relating to larger acquisitions (including, for example, AssuredPartners, the largest acquisition in our history) are more complex, including with respect to technology systems, which may divert management’s attention and resources and could adversely affect our operating results. In addition, we have made certain assumptions relating to these acquisitions that may be inaccurate, including as a result of the failure to realize expected benefits, higher than expected integration costs and unknown liabilities as well as general economic and business conditions. These assumptions relate to various matters, including projections of future revenues, non-GAAP measures, expenses and expense allocation; our ability to maintain, develop and deepen relationships with employees, including key brokers, and clients; the amount of goodwill and intangibles; our ability to realize anticipated cost savings and revenue synergies; and other unforeseen compliance, financial and strategic risks.

Damage to our reputation or culture could have a material adverse effect on our business.

Our reputation is one of our key assets. We advise our clients on and provide services related to a wide range of subjects and our ability to attract acquisition partners and attract and retain clients and employees is highly dependent upon perceptions of our expertise, level of service, ability to protect client information, trustworthiness, business practices, financial condition and other subjective qualities such as ethics, culture and values. We believe that our culture has been a critical component of our growth and success since our founding nearly 100 years ago and the failure to uphold our culture as we grow could negatively impact our reputation. Negative perceptions or publicity, including our association with clients or business partners with damaged reputations, as a result of actions taken by companies we acquire before the acquisition, as a result of marketing partnerships (for example, with a sports team or league), or from actual or alleged conduct by us or our employees, including corruption or bribery allegations or cybersecurity incidents, could damage our reputation. Negative publicity may be posted on social media or other Internet forums, whether or not true, and the speed and pervasiveness with which information can be disseminated through these channels, in particular social media, may magnify the risks noted above. Our success is also dependent on maintaining a good reputation with investors, regulators and the communities in which we operate. As we enter new jurisdictions and markets globally, negative reputational events (whether arising from regulatory matters or otherwise) may have a disproportionate impact in locations or markets where our employee and client presence is limited. Any negative publicity could potentially hinder our growth prospects in such locations or markets. Any of these matters could have a material adverse effect on our business, financial condition and results of operations. See below for additional risk factors regarding sustainability initiatives and disclosures.

Our sustainability-related aspirations, goals and initiatives, and our statements and disclosures regarding sustainability expose us to numerous risks.

Differing views and regulatory approaches regarding sustainability have made compliance with regulations, frameworks and stakeholder expectations increasingly complex and subject to risk. Our sustainability-related aspirations, goals and initiatives face scrutiny from the investment community, regulators, current and potential clients, employees, potential acquisition targets, and other stakeholders related to sustainability. This includes scrutiny regarding our goal to reach operational net zero carbon emissions (Scope 1 and Scope 2) by 2050 and our interim goal of a 50% reduction in such emissions, on a per employee basis, by 2030. We anticipate the same level of scrutiny with respect to any other goals, targets and objectives we may announce in the future, and our methodologies and timelines for pursuing them.

We could become the target of litigation, investigations or public criticism alleging that our sustainability efforts are anti-competitive, discriminatory or otherwise unlawful. For example, the State of Texas recently issued an opinion on the legality of corporate diversity, equity and inclusion (DEI) programs taking the position that such programs are potentially unlawful under certain circumstances. On the other hand, our failure or perceived failure to pursue or fulfill our sustainability-related goals, targets and objectives, to comply with ethical, social, environmental or other standards, regulations or expectations, or to satisfy various sustainability reporting standards, which vary widely across different jurisdictions, could also make us the target of litigation, investigations or public criticism. Any resulting erosion of trust and confidence could make it difficult for us to attract acquisition targets or attract and retain clients, employees or investors; result in lower sustainability ratings, exclusion of our stock from sustainability-oriented indices, and reduced demand for our stock from sustainability-focused or anti-ESG investment funds; increase our cost of borrowing; or harm our relationships with regulators and the communities in which we operate. See also “We are subject to regulation worldwide. If we fail to comply with regulatory requirements or if regulations change in a way that adversely affects our operations, we may not be able to conduct our business, or we may be less profitable.”

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If we are unable to apply technology and data analytics effectively in driving value for our clients through technology-based solutions or gain internal efficiencies and effective internal controls through the application of technology and related tools, our operating results, client relationships, ability to attract acquisition targets, growth and compliance programs could be adversely affected.

Our future success depends, in part, on our ability to collect and leverage data relating to our business and otherwise anticipate and respond effectively to the risks and opportunities presented by digital disruption, “big data” and data analytics, AI and other developments in technology. These may include new applications or insurance-related services based on AI (e.g., generative AI, machine learning), robotics, blockchain, or new approaches to data mining that impact the nature of how we generate revenue. We may be exposed to competitive risks related to the adoption and application of new technologies by established market participants (for example, through disintermediation) or new entrants such as technology companies, “Insurtech” start-up companies, and others. These new entrants are focused on using technology and innovation in an attempt to simplify and improve the client experience, increase efficiencies, alter business models and effect other potentially disruptive changes in the industries in which we operate. We must also develop and implement technology solutions and technical expertise among our employees that anticipate and keep pace with rapid and continuing changes in technology, industry standards, client preferences and internal control standards. We may not be successful in anticipating or responding to these developments on a timely and cost-effective basis and our ideas may not be accepted in the marketplace. Additionally, the effort to gain technological expertise, make use of data analytics, and develop new technologies in our business requires us to incur significant expenses. Investments in technology systems and data analytics capabilities may not deliver the benefits or perform as expected, or may be replaced or become obsolete more quickly than expected, which could result in operational difficulties or additional costs. If we cannot offer new technologies or data analytics solutions as quickly as our competitors, or if our competitors develop more cost-effective technologies, data analytics solutions or other product offerings, we could experience a material adverse effect on our operating results, client relationships, ability to attract acquisition targets, growth, and compliance programs.

In some cases, we depend on key third-party vendors and partners to provide technology and other support for our strategic initiatives. If these third parties fail to perform their obligations or cease to work with us, our ability to execute on our strategic initiatives could be adversely affected. See also “We are subject to risks associated with AI.”

We are subject to risks associated with AI.

We use AI in our business, including with respect to services provided to our clients. We have internal policies and controls governing development, procurement, deployment and the use of AI by our employees designed to align with globally recognized AI principles, maintain trust with clients and protect the company from cybersecurity threats, breaches of data privacy and intellectual property, E&O liability and regulatory enforcement risk; however, our employees could violate these policies and they or external threat actors could circumvent our controls and expose us to such risks. Furthermore, our exposure to these risks may increase if our vendors, suppliers, or other third-party providers employ AI in relation to the products or services they provide to us, as we have limited control over such use in third-party products or services. These risks include, among others, the input of confidential information, including material non-public information, in contravention of our policies or contractual restrictions to which any of the foregoing are subject, or in violation of applicable laws or regulations, including those relating to data protection and AI. This could result in such information becoming part of a data set that is accessible by other third-party AI applications and users.

Additionally, AI heavily relies on the collection and analysis of extensive data sets. The third-party models underlying our AI tools may be inadequately designed, implemented or trained, and due to the impracticality of incorporating all relevant data into the models used by AI, it is inevitable that data sets within these models will contain information that has inaccuracies and errors, and potential biases. This could potentially render such models inadequate or flawed, leading to outputs surfacing third-party intellectual property or that contain information that is biased, unethical, discriminatory, incomplete, inaccurate, misleading or poor-quality that could negatively impact the effectiveness of the technology or our services. We are exposed to the risks associated with these inaccuracies, errors and biases, along with the adverse impacts that such flawed models could have on our business and operations. Furthermore, there is a risk that the use of AI may subject the company to reputational harm and liability related to governance and ethical issues and potential litigation from third-party intellectual property holders.

The increasing adoption of AI technologies by cyber threat actors presents a significant and evolving risk to our company. These actors may leverage AI to develop more sophisticated and targeted cyberattacks, including advanced phishing schemes, malware, and data exfiltration techniques, which could compromise our controls and systems, client data, and proprietary information. Such incidents could result in operational disruptions, financial losses, reputational damage, regulatory scrutiny, and potential legal liabilities. As the capabilities of AI-driven threats continue to advance, the complexity and scale of cyber risks we face may increase, necessitating ongoing investment in robust cybersecurity measures and threat mitigation strategies.

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AI and its applications are developing rapidly. The use of this technology by our clients or underwriting enterprises may impact the way our business operates, and its use by our competitors and new market entrants with competing services derived from their AI capabilities may give them a competitive advantage. We cannot predict the effect of these changes at this time. or example, they may decrease the demand for our services or negatively affect our assumptions regarding the competitive landscape of our business. Further, the rapid development of these technologies may require significant efforts to upskill or reskill existing employees. Consequently, it is difficult to predict all risks associated with this new technology, which may eventually impact our business, results of operations, or financial condition. See also “Changes in data privacy and protection laws and regulations, or any failure to comply with such laws and regulations, could adversely affect our business and financial results.”

Our success depends, in part, on our ability to attract and retain qualified talent, including our senior management team.

We depend upon members of our senior management team, who possess extensive knowledge and a deep understanding of our business and strategy. We could be adversely affected if we fail to successfully execute our succession plans for these leaders, including our chief executive and chief financial officers, and if our succession plans are not well-received by our employees, trading partners, investors and other stakeholders. Additionally, members of our senior management team face the risk of cybersecurity and physical threats that, if carried out, could adversely affect our business.

We could be adversely affected if we fail to attract and retain talent and foster a diverse and inclusive workplace throughout our organization. Competition for talent is intense in many areas of our business, particularly in our claims management business, IT and in rapidly developing fields such as AI and data engineering. The prevalence of remote working arrangements has expanded the pool of companies that compete with us for talent. As competition for skilled professionals remains intense, employers are implementing new offerings to attract talent, including but not limited to increasing compensation, enhancing health and wellness solutions, and providing remote work options. We may have to devote significant resources to attract and retain talent, which could negatively affect our business, operating results and financial condition.

Our industry has experienced competition for brokers and in the past we have lost key brokers and groups of brokers, along with their clients, business relationships and intellectual property directly to our competition. We enter into agreements with many of our brokers and significant client-facing employees and all of our executive officers, which prohibit them from disclosing confidential information and/or soliciting our clients, prospects and employees upon their termination of employment. The confidentiality and non-solicitation provisions of such agreements terminate in the event of a hostile change in control, as defined in the agreements. Although we pursue legal actions for alleged breaches of such agreements, theft of trade secrets, breaches of fiduciary duties, intellectual property infringement and related causes of action, such legal actions may not be effective in preventing such breaches, theft or infringement. In certain cases, our competitors have solicited employees in violation of their employment agreements as a matter of standard business practice, apparently determining that the cost of defending litigation is outweighed by the benefits of acquiring our employees in this manner. Certain states like Minnesota, North Dakota, Oklahoma and Wyoming have implemented rules that would prevent employers from entering into non-competes with employees, while California has broadened the scope of its longstanding restrictions on non-competes. If more states adopt similar rules or if we fail to adequately address any of the issues referred to above, we could experience a material adverse effect on our business, operating results and financial condition.

Business disruptions could have a material adverse effect on our operations, damage our reputation and impact client relationships.

Our ability to conduct business may be adversely affected by a disruption in the infrastructure that supports our business. This includes infrastructure controlled by third-party vendors and suppliers. Such disruptions could be caused by various factors, such as cybersecurity incidents, security breaches, human error, capacity constraints, hardware failures or defects, natural or man-made disasters, climate and weather events, pandemics, fires, power outages, telecommunication failures, break-ins, sabotage, intentional acts of vandalism, acts of terrorism, civil disruption, political violence and unrest, military actions or war. While we have disaster recovery procedures in place, they may not be effective. Additionally, insurance covering such disruptions may not continue to be available at reasonable prices and may not address all potential losses or compensate us for the possible loss of clients or increase in claims and lawsuits against us. Further, because we do not control infrastructure owned by third parties, we cannot guarantee that such parties have effective recovery procedures, or sufficient funds or insurance to recover any damages, losses or other liabilities that we may incur due to business interruptions caused by disruptions to their infrastructure.

The risk of business disruption is more pronounced in certain geographic areas where a significant portion of our business is concentrated. For example, we have substantial operations in India that provide important client support and other services for our global organization. To date, the dispute between India and Pakistan involving the Kashmir region, rising tensions between India and China, incidents of terrorism in India, the potential for civil unrest and general geopolitical

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uncertainties have not adversely affected our operations in India. However, such factors could potentially affect our operations there in the future. If our access to these services is disrupted, our client relationships could be harmed, our liability for E&O could increase, and our reputation could be damaged, adversely affecting our business, operating results and financial condition.

Our business or reputation could be harmed by our reliance on third-party providers.

While we maintain some of our critical information technology systems, we are dependent on third-party providers of information technology systems and services, as well as other non-IT services, to meet the needs of our business and our clients around the world. As we do not fully control the actions of these third parties, we are subject to the risk that their decisions, actions, or inactions may adversely impact us, and replacing these service providers could create significant delay and expense. There is a risk that our third-party providers could engage in business practices that are prohibited by our internal policies or violate applicable laws and regulations. A failure by third parties to comply with service-level agreements or regulatory or legal requirements in a high-quality and timely manner, particularly during periods of our peak demand for their services, could result in economic and reputational harm to us. These third parties face their own technology, operating, business and economic risks, and any significant failures by them, including the improper use or disclosure of our confidential client, employee or company information, could cause harm to our business and reputation. An interruption in or the cessation of service by any service provider as a result of systems failures, cybersecurity incidents, capacity constraints, financial difficulties, or for any other reason could disrupt our operations, impact our ability to offer certain products and services, and result in contractual or regulatory penalties, liability claims from clients or employees, damage to our reputation, and harm to our business. See also “Business disruptions could have a material adverse effect on our operations, damage our reputation and impact client relationships.”

Sustained increases in compensation expense and the cost of employee benefits could reduce our profitability.

Compensation expense and the cost of employees’ medical and other employee benefits, substantially affect our profitability. In the past, we have occasionally experienced significant increases in these costs as a result of macro-economic factors beyond our control, including wage inflation and increases in health care costs. In 2025, our health care costs rose by approximately 20% compared to 2024 (includes impact of inflation, increased utilization and increased headcount) and our consolidated compensation expense ratio in 2025 as a percent of total consolidated revenue at 56.2% decreased slightly compared to 2024. Although we have actively sought to control increases in compensation expense and the cost of employee benefits, we can make no assurance that we will succeed in limiting future cost increases, and continued upward pressure in these costs could reduce our profitability.

Our substantial operations outside the U.S. expose us to risks different than those we face in the U.S.

In 2025, we generated approximately 33% of our combined brokerage and risk management revenues outside the U.S. Our business outside the U.S. presents operational, regulatory, economic and other risks that are different from, or greater than, the risks we face doing comparable business in the U.S. These include, among others, risks relating to:

•Maintaining awareness of and complying with a wide variety of labor practices and foreign laws, including those relating to labor and employment, data privacy requirements, AI regulations, prohibitions on corrupt payments to government officials, export and import duties, environmental policies, sustainability disclosures, as well as laws and regulations applicable to U.S. business operations abroad;

•Our employees, agents, or affiliated entities, or their respective officers, directors, employees and agents, may take actions in violation of local laws, regulations or policies, for which we might be held responsible. Actual or alleged violations could result in substantial fines, sanctions, civil or criminal penalties, debarment from government contracts, curtailment of operations in certain jurisdictions, competitive or reputational harm, litigation or regulatory action and other consequences that might adversely affect our results of operations, financial condition or strategic objectives;

•We expect relations with work councils and trade unions will continue to be satisfactory. However, work stoppages could occur in countries where such organizations exist and we may not be successful in negotiating new collective bargaining agreements. In addition, collective bargaining negotiations may (1) result in significant increases in the cost of labor, (2) divert management’s attention away from operating the business or (3) break down and result in the disruption of operations. See also “Regulatory, Legal and Accounting Risks”;

•We own interests in firms where we do not exercise management control (such as Casanueva Perez S.A.P.I. de C.V. in Mexico and Renomia, A.S. in the Czech Republic) and

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are therefore unable to direct or manage the business to realize the full range of benefits, including mitigation of risks, that could be achieved through full ownership;

•The potential costs, difficulties and risks associated with local regulations across the globe, including the risk of personal liability for directors and officers (for example, in the U.K.) and “piercing the corporate veil” risks under the corporate law regimes of certain countries;

•Difficulties in staffing and managing foreign operations. For example, we are growing our Latin America operations through acquisitions of local family-owned insurance brokerage firms. If we lose a key local employee, hiring and retaining talent locally or finding an internal candidate qualified to transfer to such location could be difficult;

•Less flexible employee relationships, which in certain circumstances have limited our ability to prohibit employees from competing with us after they are no longer employed with us or recover damages, and made it more difficult and expensive to terminate their employment;

•Conflicting regulations in the countries in which we do business;

•Political and economic instability (including risks relating to undeveloped or evolving legal systems, unstable governments, acts of terrorism, military actions and war, including between Russia and Ukraine, the Middle East and Latin America and the Caribbean). See also “Global economic conditions and geopolitical events may impact the countries, regions or industries in which we operate and adversely affect our business, results of operations and financial condition”;

•Coordinating our communications, policies and logistics across geographic distances, multiple time zones and in different languages, including during times of crisis management;

•Risks relating to our post-Brexit plan to address the loss of passporting rights between the U.K. and the European Economic Area (which we refer to as EEA) with respect to insurance brokerage services. The plan we implemented in 2020 involved transferring the EEA clients of our U.K.-based regulated entities to a Swedish subsidiary authorized in the EEA, and providing some services through a U.K. branch of such subsidiary. Although this “reverse branch” model is typical of other brokers of a similar size, EEA, regulators continue to assess their approach to this model, including as a result of, among other developments, the supervisory statement issued by the European Insurance and Occupational Pensions Authority (EIOPA) in February 2023. While we are continuously assessing the impact of these developments, it is difficult to predict such impact on our current plan;

•Unfavorable audits and exposure to additional liabilities relating to various non-income taxes (such as payroll, sales, use, value-added, net worth, property and goods and services taxes) in non-U.S. jurisdictions. In addition, our future effective tax rates could be unfavorably affected by changes in tax rates, discriminatory or confiscatory taxation, changes in the valuation of our deferred tax assets or liabilities, changes in tax laws or their interpretation and the financial results of our non-U.S. subsidiaries. See also “Changes in tax laws could adversely affect us”;

•Legal or political constraints on our ability to maintain or increase prices;

•Cash balances held in foreign banks and institutions where governments have not specifically enacted formal guarantee programs;

•Certain of our non-U.S. subsidiaries receive revenues or incur obligations in currencies that differ from their functional currencies. We must also translate the financial results of our non-U.S. subsidiaries into U.S. dollars. Although we have used foreign currency hedging strategies in the past and currently have some in place, such risks cannot be eliminated entirely, and significant changes in exchange rates may adversely affect our results of operations;

•Epidemics or pandemics at a regional or global level;

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•Lost business or other financial harm due to protectionism in the U.S. and in countries around the world, including adverse trade policies, tariffs, trade wars and other governmental actions affecting the flow of goods, services or currency, and governmental restrictions on the transfer of funds to us from our operations outside the U.S.; for example, the practice of using off-shore labor has come under increased scrutiny in the U.S. and governmental authorities or insurance carriers could seek to impose financial costs or restrictions on the use of off-shore centers of excellence such as the ones we operate in India and other international jurisdictions (see also “Business disruptions could have a material adverse effect on our operations, damage our reputation and impact client relationships”); and

•Increased tensions between countries such as the U.S., China and Russia and related trade and military policies of the U.S. government that may cause retaliation or countermeasures from other countries or regions, could further develop in ways that exacerbate the risks described above, or introduce new risks for our non-U.S. operations, such as increasing the potential that sanctions, tariffs, global mobility restrictions or other related measures may impact our business.

If any of these risks materialize, our results of operations and financial condition could be adversely affected.

Changes in tax laws could adversely affect us.

We operate in various jurisdictions and are subject to changes in applicable tax laws, treaties, or regulations in those jurisdictions. A material change in the tax laws, treaties, or regulations, or their interpretation, of any jurisdiction with which we do business, or in which we have significant operations, could adversely affect us. For example, in the Organization for Economic Cooperation and Development (which we refer to as the OECD) continues to issue reports and recommendations as part of its Base Erosion and Profit Shifting project (which we refer to as BEPS) and in 2021, it announced that 136 countries and tax jurisdictions agreed to implement a new Pillar 2 approach to international taxation. Pillar 1 exempts regulated financial institutions and we believe we qualify for such exemption.

Many countries in which we do business have adopted, or are expected to adopt, these rules which will change various aspects of the existing framework under which our tax obligations are determined. For example, the U.K., the majority of the E.U., Canada, Australia and New Zealand have now adopted nearly all aspects of these rules with limited variation from the OECD model rules. Other jurisdictions in which we do business also reacted to these efforts; for example, Bermuda enacted a corporate tax regime for the first time in 2023, which became effective in 2025.

On January 5, 2026, OECD released additional administrative guidance on the application of Pillar 2 global minimum tax rules, which are designed to ensure that large multinational enterprise (MNE) groups are subject to a minimum effective tax rate of 15% in each jurisdiction in which they operate. This guidance introduces a package of new and expanded safe harbors and simplification measures, including a “side-by-side” safe harbor regime applicable to certain U.S.-parent MNE groups, extensions and modifications to existing transitional safe harbors, and additional rules addressing the treatment of tax incentives and effective tax rate calculations. The most significant element of this guidance is the “side-by-side” safe harbor which is intended to coordinate the Pillar 2 global minimum tax regime with certain domestic minimum tax systems, including those in the U.S. Subject to eligibility requirements and elections, this safe harbor may substantially reduce or eliminate the application of Pillar 2 “top-up taxes,” including the Income Inclusion Rule and Undertaxed Profits Rule for affected MNE groups for fiscal years beginning on or after January 1, 2026. These developments, once enacted into domestic law by Pillar 2 adopters, have the potential to significantly de-risk Pillar 2 exposure for U.S. multinationals like Gallagher. Whether those enactments take effect in 2026 or later, they will need to be monitored and anticipated top-ups adjusted to reflect those enactment dates. Regardless of the adoption of this new guidance, the domestic minimum top-up aspect of Pillar 2 (referred to as “QDMTT”) and its related compliance aspects will remain for all multinationals that operate in jurisdictions that have enacted it.

We anticipate further significant developments across several jurisdictions in which we operate in 2026 and 2027. Should the jurisdictions in which we operate, and those in which we and our subsidiaries are based, choose not to implement the OECD’s January 2026 guidance in their tax treaties and domestic tax laws, particularly if the U.S. does not adopt Pillar 2, although we do not anticipate a material financial impact, we could be adversely affected by a top-up.

We face significant competitive pressures in each of our businesses.

The insurance brokerage, reinsurance brokerage and employee benefit consulting businesses are highly competitive and many insurance brokerage, reinsurance brokerage and employee benefit consulting organizations actively compete with us in one or more areas of our business around the world. Two of the firms we compete with in the global brokerage and risk management markets have larger revenues than ours. In addition, many other smaller firms that operate nationally or that

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are strong in a particular country, region or locality may have, in that country, region or locality, an office with revenues as large as or larger than those of our corresponding local office. Our third-party claims administration operation also faces significant competition from stand-alone firms as well as divisions of larger firms. Over the past decade or more, private equity sponsors have invested heavily in the insurance brokerage and third-party claims administration industries, creating new competitors and strengthening existing ones. Across all of our operations, Insurtech and technology-based start-ups are entering the business. In most cases, these businesses complement or enhance our offerings, but in some cases, they compete with us.

We believe that the primary factors determining our competitive position with other organizations in our industry are the quality of the services we offer, our data analytics capabilities, the personalized attention we provide, the individual and corporate expertise of the brokers and consultants providing the actual service to the client, our ability to address client needs across the insurance value chain by leveraging our capabilities in insurance, reinsurance, alternative risk transfer, management and administrative services, benefits consulting, and claims management, and our ability to help our clients manage their overall risk exposure and insurance or reinsurance costs. Losing business to competitors offering similar services or products at a lower cost or having other competitive advantages would adversely affect our business.

Consolidation among our existing competitors could create additional competitive pressure on us as such firms grow their market share, take advantage of strategic and operational synergies and develop lower cost structures. In addition, any increase in competition due to new legislative or industry developments could adversely affect us.

These developments include:

•Increased capital-raising by underwriting enterprises, which could result in new risk-taking capital in the industry, which in turn may lead to lower insurance premiums and commissions;

•Underwriting enterprises selling insurance directly to insureds without the involvement of a broker or other intermediary;

•Changes in our business compensation model as a result of regulatory developments;

•Federal and state governments establishing programs to provide health insurance (such as a single-payer system) or, in certain cases, property insurance in catastrophe-prone areas or other alternative market types of coverage, that compete with, or completely replace, insurance products currently offered by underwriting enterprises;

•Sustainability regulations in the U.S. and around the world, particularly those promoting the transition to a lower-carbon economy, which could create new competitive pressures around climate resilience consulting services and innovative insurance solutions;

•Continued consolidation in the financial services industry, leading to large financial services institutions offering a wider variety of services including insurance brokerage and risk management services;

•Increased competition from new market participants such as banks, accounting firms, consulting firms and Internet or other technology firms offering risk management or insurance brokerage services, or new distribution channels for insurance such as payroll firms and professional employer organizations; and

•Third-party capital providers entering the insurance and reinsurance risk transfer market offering products and capital directly to our clients. Their presence in the market has increased the competitive pressures that we face.

New competition as a result of these or other legislative or industry developments could cause the demand for our products and services to decrease, which could in turn adversely affect our results of operations and financial condition.

Volatility or declines in premiums or other adverse trends in the insurance industry may seriously undermine our profitability.

We derive much of our revenue from commissions and fees for our brokerage services. We do not determine the premiums on which our commissions are generally based. Moreover, premiums are cyclical in nature and may vary widely based on market conditions. Because of market cycles for insurance and reinsurance product pricing, which we cannot predict or control, our brokerage revenues and profitability can be volatile or remain depressed for significant periods of time.

Underwriting enterprises may seek to minimize their expenses by reducing the commission rates payable to agents or brokers such as us. The reduction of these commission rates, along with general volatility and/or declines in premiums,

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may significantly affect our profitability. Because we do not determine the timing or extent of premium pricing changes, it is difficult to forecast our commission revenues precisely, including whether they will significantly decline. As a result, we may have to adjust our budgets for future acquisitions, capital expenditures, dividend payments, debt repayments and other expenditures to account for unexpected changes in revenues, and any decreases in premium rates may adversely affect the results of our operations.

In addition, there have been and may continue to be various trends in the insurance and reinsurance markets toward alternative insurance markets including, among other things, greater levels of self-insurance, captives, rent-a-captives, risk retention groups and non-insurance capital markets-based solutions to traditional insurance. While historically we have been able to participate in certain of these activities on behalf of our clients and obtain fee revenue for such services, there can be no assurance that we will realize revenues and profitability as favorable as those realized from our traditional brokerage activities. Our ability to generate premium based commission revenue may also be challenged by the growing desire of some clients to compensate brokers based upon flat fees rather than a percentage of premium. This could negatively impact us because fees are generally not indexed for inflation and might not increase with premiums as commissions do or with the level of service provided.

Contingent and supplemental revenues we receive from underwriting enterprises are less predictable than standard commission revenues, and any decrease in the amount of these forms of revenue could adversely affect our results of operations.

A meaningful portion of our revenues consists of contingent and supplemental revenues from underwriting enterprises. Contingent revenues are paid after the insurance contract period, generally in the first or second quarter, based on the growth and/or profitability of business we placed with an underwriting enterprise during the prior year. On the other hand, supplemental revenues are paid up front, on an annual or quarterly basis, generally based on our historical premium volumes with the underwriting enterprise and additional capabilities or services we bring to the engagement. While underwriting enterprises generally maintain supplemental revenues in the current year at a pre-determined rate, that rate can change in future years as described above. If, due to the current economic environment or for any other reason, we are unable to meet an underwriting enterprise’s particular profitability, volume or growth thresholds, as the case may be, or such companies increase their estimate of loss reserves (over which we have no control), actual contingent revenues or supplemental revenues could be less than anticipated, which could adversely affect our results of operations. In the case of contingent revenues, under revenue recognition accounting standards, this could lead to the reversal of revenues in future periods that were recognized in prior periods.

We face a variety of risks in our benefit consulting operations distinct from those we face in our insurance brokerage operations.

Our benefit consulting operations face a variety of risks distinct from those faced by our brokerage operations. The portion of our revenue derived from consulting engagements and special project work is more vulnerable to reduction, postponement, cancellation or non-renewal during an economic downturn than traditional insurance brokerage commissions. A portion of our benefit consulting operation revenue is tied to assets invested by our clients, and when investment returns are adversely affected that portion of our revenue is negatively impacted. Certain areas within our retirement consulting practice may attract a higher level of regulatory scrutiny due to regulators’ historical interest in such matters, including pension-related products and investment advisory and broker-dealer services. In addition, we have made significant investments in product and knowledge development to assist clients as they navigate the complex regulatory requirements relating to employer-sponsored healthcare. New laws or regulations reducing employer-sponsored health insurance, by limiting or eliminating tax-advantaged employer-sponsored benefits or otherwise, could impact clients’ demand for our services. If we are unable to adapt our services to changes in the legal and regulatory landscape around employer-sponsored benefits, our results of operations could be adversely impacted.

We face a variety of risks in our third-party claims administration operations that are distinct from those we face in our brokerage and benefit consulting operations.

Our third party claims administration operations face a variety of risks distinct from those faced by the rest of our business, including the risks that:

•Epidemics and pandemics that reduce in-person business activity have a greater negative impact because they result in a reduction in the number of claims processed, as experienced during the years 2020, 2021 and the beginning of 2022. If a new epidemic or pandemic were to emerge, these operations could face similar negative impacts in the future;

•RISX-FACS®, our proprietary risk management information system, on which our ability to provide clients with insurance claim settlement and administration services is highly dependent, becomes inoperable for some reason. In addition, we are increasing our use of

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cloud storage and cloud computing application services supported, upgraded and maintained by third-party vendors. A disruption affecting RISX-FACS®, third-party cloud services or any other infrastructure supporting our business, including key client relationship management software, could have a material adverse effect on our operations, cause reputational harm and damage our employee and client relationships;

•The favorable trend among both underwriting enterprises and self-insured entities toward outsourcing various types of claims administration and risk management services will reverse or slow, causing our revenues or revenue growth to decline;

•Concentration of large amounts of revenue with certain clients results in greater exposure to the potential negative effects of lost business due to changes in management at such clients or changes in state government policies, in the case of our government-entity clients, or for other reasons;

•Contracting terms will become less favorable or the margins on our services will decrease due to increased competition, regulatory constraints or other developments;

•We do not satisfy regulatory requirements related to third party administrators or that regulatory developments, impose additional burdens, costs or business restrictions that make our business less profitable; for example, regulations relating to security, cybersecurity, AI and data privacy as we manage a large amount of highly sensitive and confidential information including personally identifiable information, protected health information and financial information;

•Volatility in our case volumes, which are dependent upon a number of factors and difficult to forecast accurately, could impact our revenues;

•Wage inflation, difficulty attracting and retaining talent, and rising technology costs, may impact our ability to remain competitive in the marketplace and profitably fulfill our existing contracts (other than those that provide cost-plus or other margin protection);

•We may be unable to develop further efficiencies in our claims-handling business and may be unable to obtain or retain certain clients if we fail to make adequate improvements in technology or operations; and

•Underwriting enterprises or certain large self-insured entities may create in-house servicing capabilities, including as a result of the adoption of AI that compete with our third party administration and other administration, servicing and risk management products, and we could face additional competition from potential new entrants into the global claims management services market. See also “We are subject to risks associated with AI.”

If any of these risks materialize, our results of operations and financial condition could be adversely affected.

Regulatory, Legal and Accounting Risks

Improper disclosure of confidential, personal or proprietary information and cybersecurity attacks or other security breach of our information systems, or those of third-party vendors we rely on, could result in regulatory scrutiny, legal liability or reputational harm, and could adversely affect our business, financial condition and reputation.

We collect, use, store, transmit and otherwise process, confidential, personal and proprietary information relating to our company, acquisition targets, our employees and our clients. This information includes personally identifiable information, protected health information, financial information, mergers and acquisitions information and intellectual property.

We maintain policies, procedures and technical safeguards designed to protect the security and privacy of confidential, personal and proprietary information. Nonetheless, we cannot eliminate the risk of human error, malfeasance or highly sophisticated cyber-attacks, which are heightened as a result of military actions and war, including between Russia and Ukraine, the Middle East, Latin America and the Caribbean, or other cybersecurity incidents. Further, there is a possibility that our internal processes and those of our third-party vendors to de-identify or delete confidential, personal and proprietary information may not be adequate to ensure that sensitive information is disposed of in compliance with applicable laws and regulations. In addition, our increased reliance on technologies that support remote and hybrid work and our employees’ more frequent use of personal devices and non-standard business processing as well as the increasing prevalence of sophisticated cyber-attacks using AI, such as “deep fakes,” may increase the risk of cybersecurity or data breaches from circumvention of security systems, denial-of-service attacks or other cyber-attacks, hacking, “phishing”

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attacks (including digital or telephonic impersonation), computer viruses, ransomware, malware, malicious or destructive code, employee or insider error, malfeasance, social engineering, physical breaches or other actions. It is possible that our preventive, detective, containment or remedial security controls, employee training and other aspects of our cybersecurity safeguards are not effective.

We have and continue to invest in technology security initiatives, policies, resources and employee training. The cost and operational consequences of implementing, maintaining and enhancing appropriate technical measures is high. Given the continuously evolving cyber threat landscape, it will become increasingly difficult to detect, defend against and remediate cybersecurity incidents and data breaches. If we are unable to effectively maintain and enhance our system safeguards in line with evolving cyber threats, including in connection with the integration of acquisitions, we may incur unexpected costs, including litigation costs, regulatory enforcement action, loss of clients, reputational damage, and certain of our systems may become more vulnerable to unauthorized access.

We rely on IT and third party vendors some of which have direct access to our systems, to support our business activities, including our secure processing of personal, confidential, sensitive, proprietary and other types of information. Despite ongoing efforts to improve our and our vendors’ ability to protect and defend against cyber-attacks, we may not be able to protect all of our data. From time to time, cybersecurity incidents and data breaches of certain systems on which we rely have occurred, such as computer viruses, unauthorized parties gaining access to our information technology systems, and privacy incidents, such as loss or inadvertent transmission of data, although to date we have not been materially impacted by such events. In the future, breaches of any third-party or internal systems may result from circumvention of security systems, denial-of-service, hacking, “phishing”, computer viruses, ransomware, malware, or other cyber-attacks, employee or insider error, malfeasance, social engineering, physical breaches or other actions. Furthermore, the risk from threat actors has increased due to the rapid development of AI capabilities.

With respect to our commercial arrangements with third-party vendors, we have processes designed to require third party IT outsourcing, offsite storage and other vendors to agree to maintain certain standards with respect to their storage, protection and transfer of confidential, personal and proprietary information. However, we have limited control over their security, privacy and data governance practices so there can be no assurance that we can prevent, mitigate, or remediate a potential failure of those standards and we remain at risk of a cyber or data incident due to the intentional or unintentional non-compliance by a vendor’s employee or agent, the breakdown of a vendor’s processes, or a cybersecurity incident involving vendor’s information systems. We cannot ensure that any provisions in our agreements with these vendors would be enforceable or adequate or would otherwise protect us from any liability in connection with these incidents. See also “Our business or reputation could be harmed by our reliance on third-party providers.”

We are an acquisitive organization. The process of integrating information systems of businesses we acquire is complex and exposes us to additional risk as we might not adequately identify weaknesses in the targets’ information systems or information handling, privacy and security policies and protocols, which could expose us to unexpected liabilities or make our own systems and data more vulnerable to employee or insider error, malfeasance or cybersecurity incidents. These risks may be exacerbated in connection with the integration of AssuredPartners. Any future, material cybersecurity or data incident, may cause us to experience unauthorized access, exfiltration, manipulation, corruption, loss or disclosure of our proprietary, client, employee, or other data, reputational harm, the inability to render services due to system outages or other business disruptions, loss of clients and revenue, regulatory action and scrutiny, sanctions or other statutory penalties, litigation, liability for failure to safeguard clients’ information, increases in cybersecurity costs or financial losses. Any of the foregoing may be exacerbated by a delay or failure to detect a cybersecurity incident or the full extent of such incident. In addition, disclosure or media reports of actual or perceived security vulnerabilities to our systems or those of our third-party service providers, even if no breach has been attempted or occurred, could lead to reputational harm, loss of customers and revenue, or increased regulatory actions oversight and scrutiny.

Such incidents could result in confidential, personal or proprietary information being lost or stolen, used to perpetuate fraud, maliciously made public, surreptitiously modified, or rendered inaccessible for a period of time. We cannot ensure that any limitations of liability provisions in our agreements with clients, vendors and other third parties with which we do business would be enforceable or adequate or would otherwise protect us from any liability with respect to claims arising from a cybersecurity, data or similar incident.

During a cybersecurity incident, we might have to take our systems offline, which could interfere with services to our clients or damage our reputation. While we endeavor to design and implement technologies, controls, policies and procedures to identify such incidents as quickly as possible, any response could take substantial time, and there may be extensive delays before we obtain full and reliable information. During such time we would not necessarily know the extent of the harm or how best to remediate it, and certain errors or actions could be repeated or compounded before they are discovered and remediated, all of which may further increase the costs and consequences of such incident. Any of these losses may not be insured against or be fully covered by insurance we maintain. Further, we cannot ensure that our and our third-party vendors’ existing insurance coverage will continue to be available on acceptable terms or at all. Certain

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regulations and contractual obligations require us to inform regulators, clients or affected persons in the event of a breach of confidential, personal or proprietary information on our or our third-party vendors’ systems, which we may need to deliver before we fully understand the impact of such breach resulting in damage to our reputation and our relationship with regulators and clients.

In addition, the competition for talent is high in the cybersecurity and privacy space, and we may not be able to hire, develop or retain suitable talent that we need to be capable of minimizing, identifying, mitigating or remediating these risks.

Any of the foregoing may have a material adverse effect on our business, financial condition and reputation.

Changes in data privacy and protection laws and regulations, or any failure to comply with such laws and regulations, could adversely affect our business and financial results.

We are subject to a variety of continuously evolving and developing laws and regulations globally regarding privacy, data protection, and data security, including those related to the collection, storage, handling, use, disclosure, cross-border transfer, destruction, and security of personal data. These laws apply to transfers of personal information among our affiliates, as well as to transactions we enter into with third party vendors and clients. Significant uncertainty exists as privacy and data protection laws evolve. Such laws are complex and may be interpreted and applied differently from country to country and state to state, and may create inconsistent or conflicting requirements. Some of these laws provide rights to individuals to access, correct, and delete their personal information and to obtain copies at the expense of the business entities that process their data. Some of these laws carry heavy penalties for violations, e.g., fines of up to 4% of worldwide revenue under the U.K. Data Protection Act and the European Union General Data Protection Regulation (which we refer to as GDPR), up to $20,000 per violation under the Colorado Privacy Act (which we refer to as CPA), and up to $7,500 per intentional violation under the California Consumer Privacy Act (which we refer to as CCPA). In the U.S., there is pending federal legislation and over a dozen states have proposed and some have implemented their own comprehensive data privacy bills similar to the GDPR and CCPA, with some of those laws already in effect, and others coming into effect through 2026. Despite recent privacy frameworks developed between the U.S., the U.K. and the E.U., there remains a high level of uncertainty concerning the flow of personal information between these jurisdictions, which may impair our ability to offer existing and new services and increase our costs and compliance burden.

India and other countries where we have operations outside the U.S. have proposed or have enacted sweeping data protection laws, and in some cases we are subject to sector and personal data localization laws that may require that data or personal data stay within their borders, such as India's IRDIA (Maintenance of Insurance Records) Regulation, 2015.

In addition, in the U.S., legislators are continuing to enact comprehensive cybersecurity laws. For example, we are subject to the New York State Department of Financial Services Cybersecurity Regulation for Financial Services Companies, which were substantively amended in 2023. We also expect to be subject to a variety of laws and regulations governing AI, such as the E.U. AI Act which was enacted in 2024 and will gradually enter into force during the next two years, the Colorado AI Act, and the California AI Transparency Act. Further, the issuance of the President‘s AI Executive Order entitled “Ensuring a National Policy Framework for Artificial Intelligence” introduces significant uncertainty in the regulatory landscape for AI across the United States. This uncertainty may lead to a fragmented regulatory environment, complicating compliance efforts, increasing operational risks, and potentially impacting the company’s ability to adapt to evolving legal and regulatory requirements. These laws and regulations are still evolving, and while we are continuing to assess how regulators may apply existing consumer protection, data protection and other similar laws to AI, there is uncertainty regarding the scope of new laws and how existing laws will apply. Due to this uncertainty, we may face challenges complying with existing and new laws, and our policies and governance frameworks may not be successful in mitigating these risks. See also “We are subject to risks associated with AI.”

Adhering to the increased obligations imposed by various new and emerging laws as well as the terms of our privacy notices and contractual obligations to third parties causes us to incur substantial expense in connection with developing, implementing, and securing our systems and effectively implementing data privacy governance policies for the lawful processing of personal data. Such increased obligations also result in the allocation of additional resources towards new privacy compliance processes and enhanced technologies, further contributing to our IT and compliance costs. We have implemented privacy policies detailing how we collect, use, disclose, transfer across borders, retain, and otherwise process personal information but our employees, third-party vendors or other third parties we work with may not fully adhere to

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such policies. Such non-compliance could lead to private rights of action or regulatory enforcement actions or investigations if our processing of personal data is deemed deceptive, unfair, misrepresentative of our published privacy notices or otherwise non-compliant with privacy regulation. In addition, enforcement actions and investigations by regulatory authorities related to data security incidents and privacy violations generally continue to increase. The enactment of more restrictive laws, rules, regulations, or future enforcement actions or investigations could impact us through increased costs or restrictions on our business and could result in regulatory penalties and significant legal liability.

We are subject to a number of contingencies and legal proceedings which, if determined unfavorably to us, would adversely affect our financial results.

We are or have been subject to numerous claims, tax assessments, lawsuits and proceedings that arise in the ordinary course of business. Such claims, lawsuits and other proceedings include claims for damages based on allegations that our employees or sub-agents improperly failed to procure coverage, report claims on behalf of clients, provide underwriting enterprises with complete and accurate information relating to the risks being insured, or provide clients with appropriate consulting, advisory, pension and claims handling services. There is the risk that our employees or sub-agents may fail to appropriately apply funds that we hold for our clients on a fiduciary basis. Certain of our benefits and retirement consultants provide investment advisory or decision-making services to clients. Additionally, Gallagher Re operates a securities business. If our clients experience investment losses, our reputation could be damaged and our financial results could be negatively affected as a result of claims asserted against us and lost business. Where appropriate, we have established provisions against these matters that we believe are adequate in light of current information and legal advice, and we adjust such provisions from time to time based on current material developments. The damages claimed in such matters are or may be substantial, including, in many instances, claims for punitive, treble or other extraordinary damages. It is possible that, if the outcomes of these contingencies and legal proceedings were not favorable to us, it could materially adversely affect our future financial results. In addition, our results of operations, financial condition or liquidity may be adversely affected if, in the future, our insurance coverage proves to be inadequate or unavailable or we experience an increase in liabilities for which we self-insure. We have purchased E&O insurance and other insurance to provide protection against losses that arise in such matters. Accruals for these items, net of insurance receivables, when applicable, have been provided to the extent that losses are deemed probable and are reasonably estimable. These accruals and receivables are adjusted from time to time as current developments warrant.

As more fully described in Note 15 to our 2025 consolidated financial statements, we are a defendant in various legal actions incidental to our business, including but not limited to matters related to employment practices, alleged breaches of non-compete or other restrictive covenants, theft of trade secrets, breaches of fiduciary duties, and related causes of action. We are also periodically the subject of inquiries and investigations by regulatory and tax authorities into various matters related to our business. For example, our micro-captive advisory services business has been under investigation by the IRS since 2013. We currently believe that the ultimate outcome of these proceedings, individually and in the aggregate, will not materially harm our financial position, results of operations or cash flows. However, legal proceedings and government investigations are subject to inherent uncertainties, and unfavorable rulings or other adverse events could occur, including the payment of substantial monetary damages or an injunction or other order prohibiting us from selling one or more products at all or in particular ways, precluding particular business practices or requiring other remedies, which may result in a material adverse impact on our business, results of operations or financial position. In addition, regardless of any unfavorable ruling, any such matter could expose us to negative publicity, reputational damage, harm to our client or employee relationships, or diversion of personnel and management resources, which could adversely affect our ability to recruit quality brokers and other significant employees to our business, and otherwise adversely affect our results of operations.

We could be adversely affected by violations or alleged violations of laws that impose requirements for the conduct of our overseas operations, including the FCPA, the U.K. Bribery Act or other anti-corruption laws, sanctions laws and FATCA.

In countries outside the U.S., a risk exists that our employees or third parties acting on our behalf, including correspondent brokers, consultants, introducers, partners or agents, could engage in business practices prohibited by applicable laws and regulations, including anti-bribery and anti-corruption laws, and sanctions laws such as those administered by the U.S. Department of the Treasury’s Office of Foreign Assets Control. Anti-bribery and anti-corruption laws, such as the FCPA and the U.K. Bribery Act, generally prohibit companies from making improper payments to foreign officials and require companies to keep accurate books and records and maintain appropriate internal controls. Trade and financial sanctions laws generally restrict the ability to engage in trade with, or provide goods or services, to designated governments or other parties, or may require freezing of such parties’ assets. We operate in some parts of the world that have experienced governmental corruption. In such parts of the world, in certain circumstances, local customs and practice might not be consistent with the requirements of anti-bribery and anti-corruption laws. Similarly, some of these countries do not

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implement sanctions laws and may not restrict trade with parties designated as sanctions targets under U.S., U.K. or E.U. laws.

Our policies mandate strict compliance with such laws and we devote substantial resources to programs designed to ensure compliance, including investigating business practices and taking steps to address the risk that our employees, third party representatives, partners or agents will engage in business practices that are prohibited by our policies and/or such laws and regulations.

We offer client service capabilities in many countries around the world and sometimes work through a network of third-party representatives acting on our behalf such as correspondent brokers and consultants. There is a risk that our third party representatives engage in business practices that are prohibited by our internal policies or violate applicable laws and regulations, such as the FCPA and the U.K. Anti-Bribery Act.

Violations by us or our third party representatives could result in significant internal investigation costs and legal fees, civil and criminal penalties, including prohibitions on the conduct of our business, and reputational harm.

We may also be subject to legal liability and reputational damage if we violate trade sanctions laws of the U.S., the E.U., the U.K. and other jurisdictions in which we operate. In addition, FATCA requires certain of our subsidiaries, affiliates and other entities to obtain valid FATCA documentation from payees prior to remitting certain payments to such payees and our failure to do so properly could result in penalties.

We are subject to regulation worldwide. If we fail to comply with regulatory requirements or if regulations change in a way that adversely affects our operations, we may not be able to conduct our business, or we may be less profitable.

Many of our activities throughout the world, especially regulated businesses such as our insurance brokerage, securities broker-dealer and investment advisory services, are subject to supervision and regulations promulgated by regulatory or self-regulatory bodies such as the SEC, the NYSE, the DOJ, the IRS, the Financial Crimes Enforcement Network, the FTC and FINRA in the U.S., the FCA in the U.K., the Australian Securities and Investments Commission in Australia and insurance regulators in nearly every jurisdiction in which we operate. Our retirement-related consulting and investment advisory services are subject to pension law and financial regulation in many countries. Our activities are also subject to a variety of other laws, rules and regulations addressing licensing, cybersecurity, data privacy, AI, wage-and-hour standards, employment and labor relations, competition, anti-corruption, currency, the conduct of business, reserves and the amount of local investment with respect to our operations in certain countries. For example, the DOJ updated its guidance on corporate compliance programs to include AI risk management. These and other forms of regulatory action could reduce our profitability or growth by increasing the costs of compliance, increasing the risk of costly enforcement actions, restricting the products or services we sell, the markets we enter, the methods by which we sell our products and services, or the prices we can charge for our services and the form of compensation we can accept from our clients, underwriting enterprises and third parties. As our operations grow around the world, it is increasingly difficult to monitor and enforce regulatory compliance across the organization. A compliance failure by even one of our smallest branches could lead to a loss of reputation in the local market, and litigation and/or disciplinary actions that may include compensating clients for loss, the imposition of penalties, and/or the loss of our authorization to operate. In all such cases, we would also likely incur significant internal investigation costs and legal fees.

The global nature of our operations increases the complexity and cost of compliance with laws and regulations, including increased staffing needs, the development of new policies, procedures and internal controls and providing training to employees in multiple locations, adding to our cost of doing business. Many of these laws and regulations may have differing or conflicting legal standards across jurisdictions, increasing further the complexity and cost of compliance. We experience substantial geopolitical and regulatory changes on a real-time basis, which may lead to uncertainty and increase the complexity, difficulty, and cost of compliance. In emerging markets and other jurisdictions with less developed legal systems, local laws and regulations may not be established with sufficiently clear and reliable guidance to provide us with adequate assurance that we are aware of all necessary licenses to operate our business, that we are operating our business in a compliant manner, or that our rights are otherwise protected. In addition, major political and legal developments in jurisdictions in which we do business may lead to new regulatory costs and challenges. For example, China has in place a “blocking” statute similar to that of the E.U. requiring compliance with certain Chinese laws if they conflict with U.S. laws. Rising global tensions and protectionism may also lead other countries to adopt similar blocking statutes, which could make it more difficult and costly for us to expand our operations globally.

Changes in legislation or regulations and actions by regulators, including changes in administration and enforcement policies, or the failure of state and local governments to follow through on agreed-upon state and local tax credits or other tax related incentives, could adversely affect our results of operations or require operational changes that could result in lost revenues or higher costs or hinder our ability to operate our business.

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For example, the method by which insurance brokers are compensated has received substantial scrutiny in the past because of the potential for conflicts of interest. The potential for conflicts of interest arises when a broker is compensated by two parties in connection with the same or similar transactions. The vast majority of the compensation we receive for our work as insurance and reinsurance brokers is in the form of retail commissions and fees. We receive additional revenue from underwriting enterprises, separate from retail commissions and fees, including, among other things, contingent and supplemental revenues and payments for consulting and analytics services we provide them. Future changes in the regulatory environment may impact our ability to collect these revenues. Adverse regulatory, legal or other developments regarding these revenues could have a material adverse effect on our business, results of operations or financial condition, expose us to negative publicity and reputational damage and harm our relationships with clients, underwriting enterprises or other business partners.

In addition, climate change and sustainability issues remain a significant focus for investors, clients and other business partners, while regulatory approaches across jurisdictions continue to vary widely. Some jurisdictions, such as the U.K., Australia and the State of California, are intensifying regulation and enforcement with respect to climate-related disclosures, where others are moving towards deregulation – for example, at the U.S. federal level the SEC abandoned the defense of the climate-related disclosures rule and the E.U. approved the Omnibus I directive that reduced significantly the entities subject to, and the requirements of, the Corporate Sustainability Reporting Directive (which we refer to as CSRD) and the Corporate Sustainability Due Diligence Directive (which we refer to as CSDDD). In addition, the State of Texas recently issued an opinion on the legality of corporate DEI programs taking the position that such programs are potentially unlawful under certain circumstances. Navigating these inconsistent and evolving rules may demand substantial effort and resources, potentially diverting management’s attention. Failure to effectively navigate these complexities could harm our reputation and strain relationships with regulators, investors, clients, and other business partners, which may adversely affect our business, operating results and financial condition.

Changes in our accounting estimates and assumptions could negatively affect our financial position and operating results.

We prepare our financial statements in accordance with U.S. generally accepted accounting principles (which we refer to as GAAP). These accounting principles require us to make estimates and assumptions that affect the reported amounts of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of our consolidated financial statements. We are also required to make certain judgments and estimates that affect the disclosed and recorded amounts of revenues and expenses related to revenue recognition and deferred costs - see Note 4 to our 2025 consolidated financial statements. We periodically evaluate our estimates and assumptions, including those relating to the valuation of goodwill and other intangible assets, investments, income taxes, revenue recognition, deferred costs, stock-based compensation, claims handling obligations, retirement plans, litigation and contingencies. We base our estimates on historical experience and various assumptions that we believe to be reasonable based on specific circumstances. Such estimates and assumptions could change in the future as more information becomes known, which could impact the amounts reported and disclosed in our consolidated financial statements.

Further, in 2022, the U.S. enacted the Inflation Reduction Act (which we refer to as the IRA) which, among other things, implements a corporate book minimum tax and an excise tax on stock buy backs. While guidance is still being issued and the administration may enact significant amendments to the IRA, our current understanding of the IRA suggests that we will not face significant impacts. Additionally, in July 2025, the U.S. enacted the One Big Beautiful Bill Act which includes significant provisions, such as the permanent extension of certain expiring provisions of the Tax Cuts and Jobs Act, modifications to the international tax framework and the restoration of favorable tax treatment for certain business provisions. The legislation has multiple effective dates, with certain provisions effective in 2025 and others implemented through 2027. The application of the OBBBA did not have any material impact on our financial statements for 2025. As additional guidance relating to the IRA, OBBBA, and upcoming amendments are released, our estimates related to tax and other liabilities arising under these frameworks may change. Additionally, changes in accounting standards (see Note 2 to our 2025 consolidated financial statements) could increase costs to the organization and could have an adverse impact on our future financial position and results of operations.

Limited protection of our intellectual property could harm our business and our ability to compete effectively, and we face the risk that our services or products may infringe upon the intellectual property rights of others.

We cannot guarantee that trade secret, trademark and copyright law protections, or our internal policies and procedures regarding our management of intellectual property, are adequate to deter misappropriation of our intellectual property. Existing laws of some countries in which we provide services or products may offer only limited protection of our intellectual property rights. Also, we may be unable to detect the unauthorized use of our intellectual property and take the necessary steps to enforce our rights, which may have a material adverse impact on our business, financial condition or results of operations. We cannot be sure that our services and products, or the products of others that we offer to our clients, do not infringe on the intellectual property rights of third parties, and we may have infringement claims asserted

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against us or our clients. These claims may harm our reputation, result in financial liability, consume financial resources to pursue or defend, and prevent us from offering some services or products. In addition, these claims, whether with or without merit, could be expensive, take significant time and divert management’s focus and resources from business operations. Successful challenges against us could require us to modify or discontinue our use of technology or business processes where such use is found to infringe or violate the rights of others, or require us to purchase licenses from third parties, any of which could adversely affect our business, financial condition and operating results.

Risks Relating to our Investments, Debt and Common Stock

Our clean energy investments are subject to various risks and uncertainties.

We generated tax credits under IRC Section 45 from 2009 to 2021. As of December 31, 2025, we had generated a total of $1,706 million in IRC Section 45 tax credits, of which approximately $1,102 million have been used to offset U.S. federal tax liabilities and $604 million remain unused and available to offset future U.S. federal tax liabilities.

Our ability to use tax credits under IRC Section 45 depends upon the operations in which we invested having satisfied the conditions set forth in IRC Section 45. These include, among others, the “placed-in-service” condition and requirements relating to qualified emissions reductions, coal sales to unrelated parties and at least one of the operations’ owners qualifying as a “producer” of refined coal. While we have received some degree of confirmation from the IRS relating to our ability to claim these tax credits, the IRS could ultimately determine that the operations did not satisfy the conditions set forth in IRC Section 45. The IRS audited a number of these operations. Such audits were either closed with no adjustments or, in one instance, the relevant partnership defended its position in court and prevailed.

There is a risk that foreign laws will not protect the intellectual property associated with The Chem-ModTM Solution to the same extent as U.S. laws, leaving us vulnerable to companies outside the U.S. who may attempt to copy such intellectual property. In addition, other companies may make claims of intellectual property infringement with respect to The Chem-ModTM Solution. Litigation is inherently uncertain and it is not possible for us to predict the ultimate outcome of any future claims against us by other parties.

The IRC Section 45 operations in which we have invested and the by-products from such operations may result in environmental and product liability claims and environmental compliance costs.

The construction and operation of the IRC Section 45 operations were subject to federal, state and local laws, regulations and potential liabilities arising under or relating to the protection or preservation of the environment, natural resources and human health and safety. Some environmental laws, without regard to fault or the legality of a party’s conduct, impose liability on certain entities that are considered to have contributed to, or are otherwise responsible for, the release or threatened release of hazardous substances into the environment. One party may, under certain circumstances, be required to bear more than its share or the entire share of investigation and cleanup costs at a site if payments or participation cannot be obtained from other responsible parties. By having used The Chem‐ModTM Solution at locations owned and operated by others, we and our partners may be exposed to the risk of being held liable for environmental damage from releases of hazardous substances we may have had little, if any, involvement in creating. Such risk remains even after production ceases at an operation to the extent the environmental damage can be traced to the types of chemicals or compounds used or operations conducted in connection with The Chem-ModTM Solution. Increasing attention to global climate change has resulted in an increased possibility of regulatory attention and private litigation. For example, claims have been made against certain energy companies alleging that greenhouse gas emissions constitute a public nuisance. In addition to the possibility of being named in such actions, we and our partners could face the risk of environmental and product liability claims related to concrete incorporating fly ash produced using The Chem-ModTM Solution. No assurances can be given that contractual arrangements and precautions taken to provide for assumption of these risks by facility owners or operators, or other end users, will result in that facility owner or operator, or other end user, accepting full responsibility for any environmental or product liability claim. Nor can we or our partners be certain that facility owners or operators, or other end users, fully complied with all applicable laws and regulations, and this could result in environmental or product liability claims. It is also common for private claims by third parties alleging contamination to also include claims for personal injury, property damage, nuisance, diminution of property value, or similar claims. Furthermore, many environmental, health and safety laws authorize citizen suits, permitting third parties to make claims for violations of laws or permits. Our insurance may not cover all environmental risk and costs or may not provide sufficient coverage in the event of an environmental or product liability claim, and defense of such claims can be costly, even when such defense prevails. If significant uninsured losses arise from environmental or product liability claims, or if the costs of environmental compliance increase for any reason, our results of operations and financial condition could be adversely affected.

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We have debt outstanding that could adversely affect our financial flexibility and subjects us to restrictions and limitations that could significantly impact our ability to operate our business.

As of December 31, 2025, we had total consolidated debt outstanding of approximately $13.1 billion. The level of debt outstanding each period could adversely affect our financial flexibility. We also bear risk at the time our debt matures. Our ability to make interest and principal payments, to refinance our debt obligations and to fund our acquisition program and planned capital expenditures will depend on our ability to generate cash from operations. This, to a certain extent, is subject to general economic, financial, competitive, legislative, regulatory and other factors that are beyond our control, such as an environment of rising interest rates. A small portion of our private placement debt consists of floating rate notes, and interest payments under our senior revolving credit facility are based on a floating rate which exposes us to the risk of a changing or unknown rate environment. Our indebtedness will also reduce the ability to use that cash for other purposes, including working capital, dividends to stockholders, acquisitions, capital expenditures, share repurchases, and general corporate purposes. If we cannot service our indebtedness, we may have to take actions such as selling assets, issuing additional equity or reducing or delaying capital expenditures, strategic acquisitions, and investments, any of which could impede the implementation of our business strategy or prevent us from entering into transactions that would otherwise benefit our business. Additionally, we may not be able to effect such actions, if necessary, or refinance any of our indebtedness on commercially reasonable terms, or at all.

The agreements governing our debt include covenants that, among other things, restrict our ability to dispose of assets, incur additional debt, engage in certain asset sales, mergers, acquisitions or similar transactions, create liens on assets, engage in certain transactions with affiliates, change our business or make investments, and require us to comply with certain financial and legal covenants. The restrictions in the agreements governing our debt may prevent us from taking actions that we believe would be in the best interest of our business and our stockholders and may make it difficult for us to execute our business strategy successfully or effectively compete with companies that are not similarly restricted. We may also incur future debt obligations that might subject us to additional or more restrictive covenants that could affect our financial and operational flexibility, including our ability to pay dividends. We cannot make any assurances that we will be able to refinance our debt or obtain additional financing on terms acceptable to us, or at all. A failure to comply with the restrictions under the agreements governing our debt could result in a default under the financing obligations or could require us to obtain waivers from our lenders for failure to comply with these restrictions. The occurrence of a default that remains uncured or the inability to secure a necessary consent or waiver could cause our obligations with respect to our debt to be accelerated and have a material adverse effect on our financial condition and results of operations.

Our reinsurance securities business serves from time to time as the underwriter and initial purchaser of securities (such as catastrophe bonds) issued by our reinsurance company clients. This involves us, acting as an intermediary, using our capital on hand and short-term borrowings to cover the purchase price of the securities. We place the securities with investors and use the funds we receive from them to repay our obligations. Risks specific to these short-term borrowings include counterparty risk (which is the risk that arises due to uncertainty about a counterparty’s ability to meet its obligations) with respect to the investors. Non-performance by any of our counterparties in these transactions for financial or other reasons could potentially expose us to material losses.

Credit rating downgrades would increase our financing costs and could subject us to operational risk.

If we need to raise capital in the future (for example, in order to maintain adequate liquidity, fund maturing debt obligations or finance acquisitions or other initiatives), credit rating downgrades would increase our financing costs, and could limit our access to financing sources. We would also face the risk of a credit rating downgrade if we do not retire or refinance the debt to levels acceptable to the credit rating agencies in a timely manner. Further, a downgrade to a rating below investment-grade could result in greater operational risks through increased operating costs and increased competitive pressures.

We are a holding company and, therefore, may not be able to receive dividends or other distributions in needed amounts from our subsidiaries.

We are organized as a holding company, a legal entity separate and distinct from our operating subsidiaries. As a holding company without significant operations of our own, we are dependent upon dividends and other payments from our operating subsidiaries to meet our obligations for paying principal and interest on outstanding debt obligations, for paying dividends to stockholders, repurchasing our common stock and for corporate expenses. In the event our operating subsidiaries are unable to pay sufficient dividends and other payments to us, we may not be able to service our debt, pay our obligations, pay dividends on or repurchase our common stock.

Further, we derive a meaningful portion of our revenue and operating profit from operating subsidiaries located outside the U.S. Since the majority of financing obligations as well as dividends to stockholders are paid from the U.S., it is important to be able to access the cash generated by our operating subsidiaries located outside the U.S. in the event we are unable to meet these U.S. based cash requirements.

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Funds from our operating subsidiaries outside the U.S. may be repatriated to the U.S. via stockholder distributions and intercompany financings, where necessary. A number of factors may arise that could limit our ability to repatriate funds or make repatriation cost prohibitive, including, but not limited to the imposition of currency controls and other government restrictions on repatriation in the jurisdictions in which our subsidiaries operate, fluctuations in foreign exchange rates, the imposition of withholding and other taxes on such payments and our ability to repatriate earnings in a tax-efficient manner.

In the event we are unable to generate or repatriate cash from our operating subsidiaries for any of the reasons discussed above, our overall liquidity could deteriorate and our ability to finance our obligations, including to pay dividends on or repurchase our common stock, could be adversely affected.

Future sales or other dilution of our equity could adversely affect the market price of our common stock.

An important way we grow our business is through acquisitions. One method of acquiring companies or otherwise funding our corporate activities is through the issuance of additional equity securities. The issuance of any additional shares of common or of preferred stock or convertible securities could be substantially dilutive to holders of our common stock. Moreover, to the extent that we issue restricted stock units, performance stock units, options or warrants to purchase shares of our common stock in the future and those options or warrants are exercised or as the restricted stock units or performance stock units vest, our stockholders will experience further dilution. In March 2024, we established an "at the market" equity offering program (which we refer to as an ATM program) pursuant to which we may offer and sell up to 3,000,000 shares of our common stock. We have refreshed our ATM program in the past and expect to refresh our ATM program periodically. Sales under our ATM program will result in additional dilution for our stockholders. Holders of our common stock have no preemptive rights that entitle holders to purchase their pro rata share of any offering of shares of any class or series and, therefore, such sales or offerings could result in increased dilution to our stockholders. The market price of our common stock could decline as a result of sales of shares of our common stock or the perception that such sales could occur.

Item 1B. Unresolved Staff Comments.

Not applicable.

Item 1C. Cybersecurity.

We have implemented a cybersecurity program to assess, identify, and manage risks from cybersecurity threats that could adversely and materially affect the confidentiality, integrity, and availability of our information and information systems. We maintain administrative, technical, and physical safeguards designed to protect the security and privacy of confidential, personal and proprietary information. Our cybersecurity program is aligned with notable control frameworks such as the NIST CSF (National Institute of Standards and Technology Cybersecurity Framework) and ISO (International Organization for Standardization) 27001.

Our Chief Information Security Officer (which we refer to as our CISO), working together with our Chief Information Officer (which we refer to as our CIO), oversees a team of employees dedicated to cybersecurity. Our cybersecurity team includes Business Information Security Officers (which we refer to as BISOs) in each region to lead the cybersecurity program, and to communicate ongoing updates from the cybersecurity team regarding the prevention, detection, mitigation, and remediation of cybersecurity incidents.

Our CISO regularly reports to the CIO and is an active member of our management-level enterprise risk management committee, which has broad oversight of the company’s enterprise risks, including cybersecurity risks. In addition, our CIO and CISO both attend regular meetings of the executive officer team, including our Chief Executive Officer, Chief Financial Officer, General Counsel and other senior executive officers, dedicated to compliance and risk, and report on cybersecurity matters as appropriate.Our Board of Directors has delegated primary responsibility for the oversight of cybersecurity matters to its Risk and Compliance Committee; however, the full board reviews significant cybersecurity matters as appropriate. Our CIO and CISO report on cybersecurity and information security at each quarterly meeting of the Risk and Compliance Committee.

Our cybersecurity program leverages people, processes, and technology to identify and respond to cybersecurity threats. We have a global incident response capability supported by our Security Operations Center (which we refer to as SOC) team, a managed security service provider (MSSP), ReliaQuest, and our global Cybersecurity Incident Response Team (which we refer to as CSIRT), which provides threat detection and incident response. ReliaQuest supports the operation of Gallagher’s SOC, and performs triage and escalation of event data from the security information and event management (which we refer to as SIEM) solution. This support enables 24x7 monitoring and allows Gallagher to address threats and/or detections with urgency. We have rolled out additional security technologies for new acquisitions and extended our SOC to monitor acquisitions prior to integration. We have bolstered our internal cyber forensics capability to augment our Security

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Operations capability to strengthen our ability to detect incidents, as well as to accelerate our response in parallel with our external partners.

We maintain a global cybersecurity incident response plan and related playbooks, for execution by the SOC team and CSIRT, in coordination with internal and external stakeholders, as applicable. Significant incidents are escalated to a cross-departmental team to assess materiality based on qualitative and quantitative factors. This team consists of executives representing core business functions, including, among others, information technology, legal, finance, accounting, data protection and business divisions, in consultation with third-party advisors, as applicable. We undertake periodic leadership tabletop exercises and periodic adversarial (“red team”) exercises simulating incident response under common risk scenarios. As an acquisitive organization, we have also established a program to increase our visibility into the cybersecurity environment of acquisition targets prior to closing.

Other technology partners provide additional solutions and services, including endpoint detection and response, data loss prevention, dark web monitoring, vulnerability management, next-generation firewalls, advanced web proxy, and other solutions. We have also partnered with a strategic vendor to enable acceleration of our efforts to build the cyber team and mitigate risk across the company. The relationship has brought both talent and flexibility to the team and has enabled acceleration of build-outs and integrations.

Identity management is a core component of our cyber program and solutions from Ping and Microsoft are in-place. We have also deployed a global Privileged Access Management solution, which resulted in the vaulting of all elevated user accounts that are subject to a more stringent set of controls tied to account use and duration. Additionally, we have implemented a cloud-based password reset tool offering users a highly secure and easy-to-use interface to reset passwords, regardless of device location, or browser.

Email security is a top priority for Gallagher, and we have implemented email threat detection and response services as well as capabilities to protect against phishing attacks and malicious links. Concurrently, we have rolled out phishing simulations targeted at increasing user awareness of common indicators of malicious messages. We have additionally implemented and are expanding coverage of advanced messaging features to prevent email compromise and data exfiltration, including deepfake detection and prevention.

We have established a dedicated vendor assessment team, which employs systems and processes designed to oversee, identify, and reduce the potential impact of a security incident at a third-party vendor, service provider or customer or that otherwise implicates the third-party technology and systems we use. We also require cybersecurity insurance coverage for vendors whose services or products may present a cybersecurity risk.

We continuously test and assess our cybersecurity posture, including through annual third-party risk assessments performed by reputable assessors, consultants and auditors. A global FAIR (Factor Analysis of Information Risk) assessment is conducted at least annually to update our cybersecurity risks and corresponding mitigations strategies. This process results in a quantitative understanding of our top cyber risks based on annualized loss expectancy. Our top risks, in turn, guide our prioritization of cybersecurity program maturation efforts to focus on initiatives offering Gallagher the greatest residual risk reduction.

Penetration testing is performed globally at least quarterly by our professional partners in cooperation with internal Gallagher teams. We also support leadership tabletop exercises and periodic adversarial (“red team”) exercises simulating incident response under common risk scenarios. These scenarios are updated regularly to resemble threat actor behavior trends revealed by our threat intelligence sources.

Our employees complete training on data security and our policies when they join us and annually thereafter. We review the content of our mandatory training annually and provide access to a comprehensive set of supplemental training to meet individual and role-specific needs.

As a global organization, Gallagher’s operational approach to data security and sensitive data such as PHI and PII ties to least privilege – limiting access to data, systems and applications that only align to a user’s role and responsibility. Identity management solutions and processes, such as regular user access reviews, govern the principle of least privilege. Policies inclusive of data classification and regulatory requirements for sensitive data handling mandate secure device and data handling practices, as well as controls such as an encryption and data loss prevention. Of note, Data Loss Prevention tooling has been implemented globally to monitor, prevent and detect data leakage.

Our CIO has more than 30 years of experience, including from his prior business and technology leadership roles at Aegon N.V., Citigroup, Inc. and JP Morgan Chase & Company. Our CISO has more than 20 years of cybersecurity experience. Prior to joining us, he was Senior Vice President, Chief Information Security Officer at Brighthouse Financial. Before then, he served as Technology Vice President & Chief Information Security Officer for GE Healthcare. He started his career at Allstate Insurance Company. He also holds security, privacy and risk certifications, including Certified Information Systems Auditor, Certified Information Security Manager and Certified Information Systems Security Professional.

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Gallagher remains committed to maintaining and improving our existing security posture. We regularly monitor and assess the policies and procedures in place and continue to work with leading global cybersecurity investigation firms with expertise in data privacy incident response and containment.

We, including our third-party vendors, have experienced cybersecurity incidents and threats and may continue to experience them in the future. Based on the information available as of the date of this Annual Report on Form 10-K, we believe that during the last three fiscal years risks from cybersecurity threats, including as a result of previous cybersecurity incidents, have not materially affected us, including our business strategy, results of operations or financial condition, and as of the date of this Annual Report on Form 10-K, the Company is not aware of any material risks from cybersecurity threats that are reasonably likely to do so. However, we cannot eliminate all risks from cybersecurity threats or provide assurances that the Company will not be materially affected by such risks in the future. Due to evolving cybersecurity threats, we may not be able to protect all information systems and, as an acquisitive organization, integrating information systems as we acquire new businesses may expose us to unexpected liabilities or increase our vulnerability. There can be no guarantee that our policies, programs and controls, and those of our third-party vendors, including those described in this section, will be sufficient to protect our information, information systems or other property. Additional information on cybersecurity risks we face is discussed in Item 1A of Part I, “Risk Factors,” which should be read in conjunction with the foregoing information.

Item 2. Properties.

The executive offices of our corporate segment and certain subsidiary and branch facilities of our brokerage and risk management segments are located at 2850 Golf Road, Rolling Meadows, Illinois, where we own approximately 360,000 square feet of space, and can accommodate 2,000 employees at peak capacity.

Elsewhere, we generally operate in leased premises related to the facilities of our brokerage and risk management operations. We prefer to lease office space rather than own real estate related to the branch facilities of our brokerage and risk management segments. Certain of our office space leases have options permitting renewals for additional periods. In addition to minimum fixed rentals, a number of our leases contain annual escalation clauses generally related to increases in an inflation index. See Notes 13 and 15 to our 2025 consolidated financial statements for information with respect to our lease commitments as of December 31, 2025.

Item 3. Legal Proceedings.

Please see the information set forth in Note 15 to our consolidated financial statements, included herein, under “Litigation, Regulatory and Taxation Matters.”

Item 4. Mine Safety Disclosures.

Not applicable.

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Information About Our Executive Officers

Set forth below are the names, ages, positions and business backgrounds of our executive officers as of the date hereof:

Name Age Position and Year First Elected

Walter D. Bay 63 Corporate Vice President, General Counsel, Secretary since 2007

With the exception of Mr. Bloom, we have employed each such person principally in management capacities for more than the past five years. All executive officers are appointed annually and serve at the discretion of our board of directors.

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Part II

Item 5. Market for the Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.

Our common stock is listed on the New York Stock Exchange, trading under the symbol “AJG.”

As of January 31, 2026, there were approximately 2,000 holders of record of our common stock.

(c)Issuer Purchases of Equity Securities

The following table shows the purchases of our common stock made by or on behalf of us or any “affiliated purchaser” (as such term is defined in Rule 10b-18(a)(3) under the Securities Exchange Act of 1934, as amended) of us for each fiscal month in the three-month period ended December 31, 2025:

(1)Amounts in this column include shares of our common stock purchased by the trustees of trusts established under our Deferred Equity Participation Plan (which we refer to as the DEPP), our Deferred Cash Participation Plan (which we refer to as the DCPP) and our Supplemental Savings and Thrift Plan (which we refer to as the Supplemental Plan), respectively. These plans are considered to be unfunded for purposes of federal tax law since the assets of these trusts are available to our creditors in the event of our financial insolvency. The DEPP is an unfunded, non-qualified deferred compensation plan that generally provides for awards to certain of our key executives that do not vest and/or distribute until participants reach age 62 (or the one-year anniversary of the date of grant for participants over the age of 61). Under sub‐plans of the DEPP for certain production staff, the plan generally provides for vesting and/or distributions no sooner than five years from the date of awards, although certain awards vest and/or distribute after the earlier of fifteen years or the participant reaching age 65. See Note 10 to our 2025 consolidated financial statements for more information regarding the DEPP. The DCPP is an unfunded, non-qualified deferred compensation plan for certain key employees, other than executive officers, that generally provides for vesting and/or distributions no sooner than five years from the date of awards. Under the terms of the DEPP and the DCPP, we may contribute cash to the trust and instruct the trustee to acquire a specified number of shares of our common stock on the open market or in privately negotiated transactions. For the fourth quarter of 2025, we instructed the trustee for the DEPP and the DCPP to reinvest dividends on shares of our common stock held by these trusts and to purchase our common stock using cash that we contributed to the DCPP related to 2025 awards under the DCPP. The Supplemental Plan is an unfunded, non-qualified deferred compensation plan that allows certain highly compensated employees to defer compensation, including match amounts by the Company, on a before-tax basis or after-tax basis. Under the terms of the Supplemental Plan, all amounts credited to an employee’s account may be deemed invested, at the employee’s election, in a number of investment options that include various mutual funds, an annuity product and a fund representing our common stock. When an employee elects to have some or all of the amounts credited to the employee’s account under the Supplemental Plan deemed to be invested in the fund representing our common stock, the trustee of the trust for the Supplemental Plan purchases shares of our common stock in a number sufficient to ensure that the trust holds a number of shares of our common stock with a value equal to the amounts deemed invested in the fund representing our common stock. This is to ensure that at the time when an employee becomes entitled to a distribution under the terms of the Supplemental Plan, any amounts deemed to be invested in the fund representing our common stock are distributed in the form of shares of our common stock held by the trust. We established the trusts for the DEPP, the DCPP and the Supplemental Plan to assist us in discharging our deferred compensation

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obligations under these plans. All assets of these trusts, including any shares of our common stock purchased by the trustees, remain, at all times, assets of the Company, subject to the claims of our creditors in the event of our financial insolvency. The terms of the DEPP, the DCPP and the Supplemental Plan do not provide for a specified limit on the number of shares of common stock that may be purchased by the respective trustees of the trusts.

(2)The average price paid per share is calculated on a settlement basis and does not include commissions.

(3)Effective July 28, 2021, the board of directors approved a common stock repurchase plan of up to $1.5billion of common stock. Repurchases of common stock may be effected from time to time through open market purchases, trading plans established in accordance with the U.S. Securities and Exchange Commission’s rules, accelerated stock repurchases, private transactions or other means, depending on satisfactory market conditions, applicable legal requirements and other factors. The repurchase plan has no expiration date and we are under no commitment or obligation to repurchase any particular amount of our common stock under the plan. At our discretion, we may suspend the repurchase plan at any time.

(4)Dollar values stated in millions.

Item 6. [Reserved].

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Introduction

The following discussion and analysis should be read in conjunction with our consolidated financial statements and the related notes included in Item 8 of this annual report. In addition, please see “Information Regarding Non-GAAP Measures and Other” beginning on page 38 for a reconciliation of the non-GAAP measures for adjusted total revenues, organic commission, fee and supplemental revenues and adjusted EBITDAC to the comparable GAAP measures, as well as other important information regarding these measures.

We are engaged in providing insurance brokerage, reinsurance brokerage, consulting services, and third-party property/casualty claims settlement and administration services to entities and individuals around the world. We believe that one of our major strengths is our ability to deliver comprehensively structured insurance and risk management services to our clients. Our brokers, agents and administrators act as intermediaries between underwriting enterprises and our clients and we do not assume net underwriting risks. We are headquartered in Rolling Meadows, Illinois, and provide brokerage, risk management and consulting services in approximately 130 countries around the world through our owned operations and a network of correspondent brokers and consultants and third-party property/casualty claims settlement and administration services through a network of offices located throughout Australia, Canada, New Zealand, the U.K. and the U.S. In 2025, we expanded, and expect to continue to expand, our international operations through both acquisitions and organic growth. We generate approximately 67% of our revenues for the combined brokerage and risk management segments domestically, with the remaining 33% generated internationally, primarily in Australia, Canada, New Zealand and the U.K. (based on 2025 revenues). We have three reportable segments: brokerage, risk management and corporate. Brokerage and risk management contributed approximately 87% and 13%, respectively, to 2025 revenues. Our major sources of operating revenues are commissions, fees and supplemental and contingent revenues from brokerage operations and fees from risk management operations. Interest income, premium finance revenues and other income is generated from invested cash and fiduciary funds and revenue from premium financing.

Prior Year Discussion of Results and Comparisons

For information on fiscal 2024 results and similar comparisons, see "Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations" of our Form 10-K for the fiscal year ended December 31, 2024.

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Summary of Financial Results - Year Ended December 31,

See the Reconciliations of Non-GAAP Measures on page 38.

(In millions, except per share data)

Brokerage Segment

Net earnings margin 16.8 % 17.0 % - 14 bpts

Adjusted EBITDAC margin 36.5 % 35.1 % + 145 bpts

Risk Management Segment

Net earnings margin (before reimbursements) 11.6 % 12.1 % - 51 bpts

Adjusted EBITDAC margin (before reimbursements) 21.2 % 20.7 % + 54 bpts

Corporate Segment

Diluted net loss per share $ (2.81) $ (2.24) $ (1.74) $ (1.61)

Total Company

Total Brokerage and Risk Management Segment

In our corporate segment, net after-tax (loss) earnings from our clean energy investments was $(5) million in both 2025 and 2024. At this time, we anticipate our clean energy investments will produce after-tax losses in 2026.

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The following provides information that management believes is helpful when comparing revenues before reimbursements, net earnings, EBITDAC and diluted net earnings per share for 2025 and 2024. In addition, these tables provide reconciliations to the most comparable GAAP measures for adjusted revenues, adjusted EBITDAC and adjusted diluted net earnings per share. Reconciliations of EBITDAC for the brokerage and risk management segments are provided on pages 45 and 51 of this filing.

Year Ended December 31 Reported GAAP to Adjusted Non-GAAP Reconciliation:

(In millions, except per share data)

Effective income tax rate impact — — — (7) — — — (0.03)

Levelized foreign currency translation — 57 — 8 — 13 — 0.04

Net (gains) on divestures (2) — (1) — (2) — — —

Acquisition related adjustments — — 3 — 4 — 0.01 —

Amortization of intangibles assets — — 16 10 — — 0.06 0.04

Levelized foreign currency translation — (1) — — — — — —

Legal, tax and benefit plan related — — 42 3 78 — 0.16 0.02

Clean energy-related — (5) — (2) — (2) — (0.01)

Total Brokerage and Risk

*For the year ended December 31, 2025, the pretax impact of the brokerage segment adjustments totals $1,482 million, mostly due to non-cash period expenses related to intangible amortization, with a corresponding adjustment to the provision for income taxes of $375 million relating to these items. For the year ended December 31, 2025, the pretax impact of the risk management segment adjustments totals $45 million, with a corresponding adjustment to the provision for income taxes of $11 million relating to these items. For the year ended December 31, 2025, the pretax impact of the corporate segment adjustments totals $200 million, with a corresponding adjustment to the benefit for income taxes of $51 million relating to these items and other tax items noted on page 56. For the corporate segment, the clean energy related adjustments are described on page 56.

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Reconciliation of Non-GAAP Measures - Pre-tax Earnings and Diluted Net Earnings per Share

(In millions except share and per share data)

Net (gains) on divestitures (24) (6) (18) — (18) (0.07)

Net (gains) on divestitures (2) (1) (1) — (1) —

Acquisition integration 9 2 7 — 7 0.03

Workforce and lease termination 12 3 9 — 9 0.03

Acquisition related adjustments 4 1 3 — 3 0.01

Amortization of intangible assets 22 6 16 — 16 0.06

Net (gains) on divestitures (24) (6) (18) — (18) (0.08)

Effective income tax rate impact — 7 (7) — (7) (0.03)

Levelized foreign currency translation 13 5 8 — 8 0.04

Acquisition integration 3 1 2 — 2 0.01

Workforce and lease termination 8 2 6 — 6 0.03

Amortization of intangible assets 14 4 10 — 10 0.04

Legal and tax related — (3) 3 — 3 0.02

Clean energy related (2) — (2) — (2) (0.01)

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Acquisition of AssuredPartners and Woodruff Sawyer

On August 18, 2025, we acquired all of the issued and outstanding stock of Dolphin TopCo, Inc., the holding company of AssuredPartners, Inc., a Delaware corporation (which we refer to, together with its subsidiaries, as “AssuredPartners”) for gross consideration of $13.8 billion. AssuredPartners is a leading U.S. insurance broker with client capabilities across commercial property/casualty, specialty, employee benefits and personal lines with operations in the U.K. and Ireland. We raised $8.5 billion of cash in our December 11, 2024 follow-on common stock offering and borrowed $5.0 billion of cash in our December 19, 2024 senior notes issuance (which we refer to, together with the follow-on common stock offering, as the AssuredPartners Financing) to fund the transaction. On January 7, 2025, we received an additional $1.3 billion of cash due to the exercise by the underwriters of the overallotment provision related to the follow-on common stock offering. AssuredPartners had over 10,900 employees serving through offices located across the U.S., U.K. and Ireland.

On April 10, 2025, we acquired all of the issued and outstanding stock of Woodruff-Sawyer & Co. (which we refer to as Woodruff Sawyer) for consideration of $1.2 billion. We funded the transaction using cash on hand. Woodruff Sawyer provides a full suite of commercial property/casualty products, employee benefits solutions and risk management services with a focus on middle and large market clients. Immediately prior to closing, Woodruff Sawyer had over 600 employees serving clients through 14 U.S. offices and one U.K. office.

Insurance Market Overview

Fluctuations in premiums charged by property/casualty underwriting enterprises have a direct and potentially material impact on the insurance brokerage industry. Commission revenues are generally based on a percentage of the premiums paid by insureds and normally follow premium levels. Insurance premiums are cyclical in nature and may vary widely based on market conditions. Various factors, including competition for market share among underwriting enterprises, increased underwriting capacity and improved economies of scale following consolidations, can result in flat or reduced property/casualty premium rates (a “soft” market). A soft market tends to put downward pressure on commission revenues. Various countervailing factors, such as greater than anticipated loss experience, unexpected loss exposure and capital shortages, can result in increasing property/casualty premium rates (a “hard” market). A hard market tends to favorably impact commission revenues. Hard and soft markets may be broad-based or more narrowly focused across individual product lines or geographic areas. As markets harden, buyers of insurance (such as our brokerage clients), have historically tried to mitigate premium increases and the higher commissions these premiums generate, including by raising their deductibles and/or reducing the overall amount of insurance coverage they purchase. As the market softens, or costs decrease, these trends have historically reversed. During a hard market, buyers may switch to negotiated fee in lieu of commission arrangements to compensate us for placing their risks, or may consider the alternative insurance market, which includes self-insurance, captives, rent-a-captives, risk retention groups and capital market solutions to transfer risk. Our brokerage units are very active in these markets as well. While increased use by insureds of these alternative markets historically has reduced commission revenue to us, such trends generally have been accompanied by new sales and renewal increases in the areas of risk management, claims management, captive insurance and self-insurance services and related growth in fee revenue. Inflation tends to increase the levels of insured values and risk exposures, resulting in higher overall premiums and higher commissions. However, the impact of hard and soft market fluctuations has historically had a greater impact on changes in premium rates, and therefore on our revenues, than inflationary pressures.

We use the Council of Insurance Agents & Brokers (which we refer to as the CIAB) insurance pricing quarterly survey as an indicator of the insurance rate environment. The CIAB represents the leading domestic and international insurance brokers, who write approximately 85% of the commercial property/casualty premiums in the U.S. The fourth quarter 2025 survey had not been published as of the filing date of this report. The first three 2025 quarterly surveys indicated that U.S. commercial property/casualty rates increased by 4.2%, 3.7%, and 1.6% on average, for the first, second and third quarters of 2025, respectively, indicating overall continued price firming.

We are seeing carrier competition across property related coverages and continued caution within casualty lines, particularly in the U.S. We believe these trends are likely to persist throughout 2026. We estimate global insured natural catastrophe losses were approximately $129 billion during 2025, below the 5-year annual average loss of $155 billion. More normalized global loss activity during 2026 may cause insurance and/or reinsurance carriers to increase property pricing upon renewal. Additionally, elevated loss trends and continued profitability concerns within casualty coverages, could lead to a more difficult rate and conditions environment in certain lines. The combination of increasing insurable values (due to inflation, including wage inflation), a tight labor market and low unemployment is likely contributing to increases in client insured exposures.

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We expect that our history of strong new business generation, solid retentions and enhanced value-added services for our carrier partners should all result in further organic growth opportunities around the world. Our professionals can demonstrate their expertise and high-quality, value-added capabilities by strengthening our clients’ insurance portfolios and delivering insurance and risk management solutions within our clients’ budget.

Business Combinations and Dispositions

See Note 3 to our 2025 consolidated financial statements for a discussion of our 2025 business combinations.

Results of Operations

Information Regarding Non-GAAP Measures and Other

In the discussion and analysis of our results of operations that follows, in addition to reporting financial results in accordance with GAAP, we provide information regarding EBITDAC, EBITDAC margin, adjusted EBITDAC, adjusted EBITDAC margin, diluted net earnings per share, as adjusted (adjusted EPS), adjusted revenue, adjusted compensation and operating expenses, adjusted compensation expense ratio, adjusted operating expense ratio and organic revenue. These measures are not in accordance with, or an alternative to, the GAAP information provided in this report. We believe that these presentations provide useful information to management, analysts and investors regarding financial and business trends relating to our results of operations and financial condition or because they provide investors with measures that our chief operating decision maker uses when reviewing the Company’s performance. See further below for definitions and additional reasons each of these measures is useful to investors. Our industry peers may provide similar supplemental non-GAAP information with respect to one or more of these measures, although they may not use the same or comparable terminology and may not make identical adjustments. The non-GAAP information we provide should be used in addition to, but not as a substitute for, the GAAP information provided. As disclosed in our most recent Proxy Statement, we make determinations regarding certain elements of executive officer incentive compensation, performance share awards and annual cash incentive awards, partly on the basis of measures related to adjusted EBITDAC.

Adjusted Non-GAAP presentation - We believe that the adjusted non-GAAP presentation of our 2025 and 2024 information, presented on the following pages, provides stockholders and other interested persons with useful information regarding certain financial metrics that may assist such persons in analyzing our operating results as they develop a future earnings outlook for us. The after-tax amounts related to the adjustments were computed using the normalized effective tax rate for each respective period.

•Adjusted measures - Revenues (for the brokerage segment), revenues before reimbursements (for the risk management segment), net earnings, compensation expense and operating expense, respectively, each adjusted to exclude the following, as applicable:

◦Net gains (losses) on divestitures, which are primarily net proceeds received related to sales of books of business and other divestiture transactions, such as the disposal of a business through sale or closure.

◦Acquisition integration costs, which include costs related to certain large acquisitions (including the acquisitions of the Willis Towers Watson plc treaty reinsurance brokerage operations (which we refer to as Willis Re), Buck, Cadence Insurance, Eastern Insurance, My Plan Manager, Woodruff Sawyer and AssuredPartners), outside the scope of our usual tuck-in strategy, not expected to occur on an ongoing basis in the future once we fully assimilate the applicable acquisition. These costs are typically associated with redundant workforce, compensation expense related to amortization of certain retention bonus arrangements, extra lease space, duplicate services and external costs incurred to assimilate the acquisition into our IT related systems.

◦Transaction-related costs, which are associated with completed, future and terminated acquisitions. Costs primarily relate to the acquisitions of Willis Re, Buck, Cadence Insurance, Eastern Insurance, all of which closed in 2023, as well as Woodruff Sawyer and AssuredPartners, which closed in April 2025 and August 2025, respectively. These include costs related to regulatory filings, legal and accounting services, insurance and incentive compensation.

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◦Workforce related charges, which primarily include severance costs (either accrued or paid) related to employee terminations and other costs associated with redundant workforce.

◦Lease termination related charges, which primarily include costs related to terminations of real estate leases and abandonment of leased space.

◦Acquisition related adjustments principally relate to changes in estimated acquisition earnout payables adjustments and acquisition related compensation charges. In addition, from time to time may include changes in balance sheet estimates arising from conforming accounting principles, purchase-related true-ups and other balance sheet adjustments made after the closing date; the net impact on the results for first quarter 2024 was approximately $26 million of revenues and approximately $28 million of compensation expense.

◦Amortization of intangible assets which reflects the amortization of customer/expiration lists, non-compete agreements, trade names and other intangible assets acquired through our merger and acquisition strategy, the impact to amortization expense of acquisition valuation adjustments to these assets as well as non-cash impairment charges.

◦The impact of foreign currency translation, as applicable. The amounts excluded with respect to foreign currency translation are calculated by applying current year foreign exchange rates to the same period in the prior year.

◦Effective income tax rate impact, which levelizes the prior year for the change in current year tax rates.

◦Legal and tax related, which represents the impact of adjustments in 2025 and 2024 related to costs associated with legal and tax matters.

◦Benefit plan related, which represents the impact of adjustments in 2025 related to costs associated with the termination of the Gallagher U.S. defined pension plan and other benefit plan changes.

•Adjusted ratios - Adjusted compensation expense and adjusted operating expense, respectively, each divided by adjusted revenues.

Non-GAAP Earnings Measures

•EBITDAC and EBITDAC Margin - EBITDAC is net earnings before interest, income taxes, depreciation, amortization and the change in estimated acquisition earnout payables and EBITDAC margin is EBITDAC divided by total revenues (for the brokerage segment) and revenues before reimbursements (for the risk management segment). These measures for the brokerage and risk management segments provide a meaningful representation of our operating performance for the overall business and provide a meaningful way to measure our financial performance on an ongoing basis.

•EBITDAC, as Adjusted and EBITDAC Margin, as Adjusted - Adjusted EBITDAC is EBITDAC adjusted to exclude net gains on divestitures, acquisition integration costs, workforce related charges, lease termination related charges, acquisition related adjustments, transaction related costs, and the period-over-period impact of foreign currency translation, as applicable and Adjusted EBITDAC margin is Adjusted EBITDAC divided by total adjusted revenues (defined above). These measures for the brokerage and risk management segments provide a meaningful representation of our operating performance, and are also presented to improve the comparability of our results between periods by eliminating the impact of the items that have a high degree of variability.

•EPS, as Adjusted and Net Earnings, as Adjusted - Adjusted net earnings have been adjusted to exclude the after-tax impact of net gains on divestitures, acquisition integration costs, the impact of foreign currency translation, workforce related charges, lease termination related charges, acquisition related adjustments, transaction related costs,

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amortization of intangible assets, and effective income tax rate impact, as applicable. Adjusted EPS is Adjusted Net Earnings divided by diluted weighted average shares outstanding. This measure provides a meaningful representation of our operating performance (and as such should not be used as a measure of our liquidity), and for the overall business is also presented to improve the comparability of our results between periods by eliminating the impact of the items that have a high degree of variability.

Organic Revenues (a non-GAAP measure) - Organic revenue change measures the year-over-year percentage change in organic revenue. For the brokerage segment, organic revenue consists of base commission and fee revenues, supplemental revenues and contingent revenues excludes the first twelve months of such revenues generated from acquisitions and such revenues related to divested operations which include disposals of a business through sale or closure, estimate changes, run-off of a business and the restructuring and/or repricing of programs and products in each year presented. Such revenues are excluded from organic revenues in order to help interested persons analyze the revenue growth associated with the operations that were a part of our business in both the current and prior year. In order to improve the comparability of our results between periods, we further exclude the period-over-period impact of foreign currency translation; revenue from certain large life product sales within Gallagher’s Executive Life and Benefits practice group (which are typically large, singular transactions with a high degree of variability in amount and timing); and revenue attributable to changes in assumptions used to calculate estimated deferred revenues, which impact the quarterly timing of revenues during the annual contract period. For the risk management segment, organic revenues consists of fee revenues excludes the first twelve months of such revenues generated from acquisitions and such revenues related to divested operations in each year presented. In order to improve the comparability of our results between periods, we further exclude the period-over-period impact of foreign currency translation

These revenue items are excluded from organic revenues in order to determine a comparable, but non-GAAP, measurement of revenue growth that is associated with the revenue sources that are expected to continue in the current year and beyond as well as eliminating the impact of the items that have a high degree of variability. We have historically viewed organic revenue growth as an important indicator when assessing and evaluating the performance of our brokerage and risk management segments. We also believe that using this non-GAAP measure allows readers of our financial statements to measure, analyze and compare the growth from our brokerage and risk management segments in a meaningful and consistent manner.

Reconciliation of Non-GAAP Information Presented to GAAP Measures - This report includes tabular reconciliations to the most comparable GAAP measures, as follows: for EBITDAC (on pages 45 and 51), for adjusted revenues, adjusted EBITDAC and adjusted diluted net earnings per share (on page 37), for organic revenue measures (on pages 46 and 51), respectively, for the brokerage and risk management segments, for adjusted compensation and operating expenses and adjusted EBITDAC margin (on page 48), respectively, for the brokerage segment and (on page 52) for the risk management segment.

Brokerage

AJG US Equity

AJG · 10-K · period ended 2025-12-31

Item 1A. Risk Factors.

Item 1B. Unresolved Staff Comments.

Item 1C. Cybersecurity.

Item 2. Properties.

Item 3. Legal Proceedings.

Item 4. Mine Safety Disclosures.

Item 5. Market for the Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.

Item 6. [Reserved].

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

AJG US Equity☆

AJG · 10-K · period ended 2025-12-31

Item 1A. Risk Factors.

Item 1B. Unresolved Staff Comments.

Item 1C. Cybersecurity.

Item 2. Properties.

Item 3. Legal Proceedings.

Item 4. Mine Safety Disclosures.

Item 5. Market for the Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities.

Item 6. [Reserved].

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

AJG US Equity