Arthur J. Gallagher & Co. · Earnings release · 8-K Exhibit 99

NEWS RELEASE

ARTHUR J. GALLAGHER & CO. ANNOUNCES

FOURTH QUARTER AND FULL YEAR 2025 FINANCIAL RESULTS

ROLLING MEADOWS, IL, January 29, 2026 — Arthur J. Gallagher & Co. (NYSE: AJG) today reported its financial results for the quarter

ended December 31, 2025. Management will host a webcast conference call to discuss these results on Thursday, January 29, 2026 at 5:15 p.m. ET/4:15 p.m. CT. To listen to the call, and for printer-friendly formats of this release and the

“CFO Commentary” and “Supplemental Quarterly Data,” which may also be referenced during the call, please visit ajg.com/IR. These documents contain both GAAP and non-GAAPmeasures. Investors and other users of this information should read carefully the section entitled “Information Regarding Non-GAAP Measures” beginning on page 9.

Summary of Financial Results - Fourth Quarter

Revenues Before

Reimbursements

Net Earnings (Loss)

EBITDAC

Diluted Net Earnings

(Loss) Per Share

Segment

(in millions)

(in millions)

(in millions)

Brokerage, as reported

$

$

$

$

$

$

$

$

Net losses (gains) on divestitures

)

1

)

1

)

1

)

—

Acquisition integration

—

—

Workforce and lease termination

—

—

Acquisition related adjustments

—

—

Amortization of intangible assets

—

—

—

—

Effective income tax rate impact

—

—

—

1

—

—

—

Levelized foreign currency translation

—

—

5

—

8

—

Brokerage, as adjusted *

Risk Management, as reported

Net (gains) on divestitures

(1

)

—

(1

)

—

(1

)

—

—

—

Acquisition integration

—

—

1

—

2

2

—

—

Workforce and lease termination

—

—

1

3

2

2

—

Acquisition related adjustments

—

—

3

—

3

—

—

Amortization of intangible assets

—

—

4

3

—

—

Levelized foreign currency translation

—

3

—

1

—

1

—

—

Risk Management, as adjusted *

Corporate, as reported

—

)

)

)

)

)

)

Transaction-related costs

—

—

Legal, tax & benefit plan related

—

—

—

—

—

Clean energy related

—

(5

)

—

(1

)

—

(2

)

—

—

Corporate, as adjusted *

—

9

)

)

)

)

)

)

Total Company, as reported

$

$

$

$

$

$

$

$

Total Company, as adjusted *

$

$

$

$

$

$

$

$

Total Brokerage & Risk Management, as reported

$

$

$

$

$

$

$

$

Total Brokerage & Risk Management, as adjusted *

$

$

$

$

$

$

$

$

*

For fourth quarter 2025, the pretax impact of the Brokerage segment adjustments totals $533 million,

mostly due to non-cash period expenses related to intangible amortization, with a corresponding adjustment to the provision for income taxes of $136 million relating to these items. For fourth quarter

2025, the pretax impact of the Risk Management segment adjustments totals $12 million, with a corresponding adjustment to the provision for income taxes of $3 million relating to these items. For fourth quarter 2025, the pretax impact of

the Corporate segment adjustments totals $90 million, with a corresponding adjustment to the benefit for income taxes of $29 million relating to these items. A detailed reconciliation of the 2025 and 2024 provision (benefit) for income

taxes is shown on pages 14 and 15.

“We had an excellent fourth quarter and a terrific 2025!” said J. Patrick Gallagher, Jr.,

Chairman and CEO.

“Our two-pronged revenue growth strategy, that’s organic and M&A, drove

double-digit top line growth for the 20th straight quarter. T1Fourth quarter revenue growth for our combined Brokerage and Risk Management segments was in excess of 30% and included organic revenue growth of 5%. T2Net earnings margin was 10.2%, adjusted

EBITDAC margin was 30.8% and adjusted EBITDAC grew 30%.

“T3We finished 2025 with 21% growth in revenue, 6% organic growth, 26% growth in adjusted

EBITDAC and completed 33 mergers with more than $3.5 billion in estimated annualized revenue. Another fantastic year.

“We have excellent

momentum entering 2026 and our talented colleagues are executing on our value creation strategy. We are extremely excited about 2026 and believe we are just getting started!”

Summary of Financial Results - Year Ended December 31

Revenues Before

Reimbursements

Net Earnings (Loss)

EBITDAC

Diluted Net Earnings

(Loss) Per Share

Segment

(in millions)

(in millions)

(in millions)

Brokerage, as reported

$

$

$

$

$

$

$

$

Net (gains) on divestitures

)

)

)

)

)

)

)

)

Acquisition integration

—

—

Workforce and lease termination

—

—

Acquisition related adjustments

—

)

Amortization of intangible assets

—

—

—

—

Effective income tax rate impact

—

—

—

(7

)

—

—

—

)

Levelized foreign currency translation

—

—

8

—

—

Brokerage, as adjusted *

Risk Management, as reported

Net (gains) on divestitures

(2

)

—

(1

)

—

(2

)

—

—

—

Acquisition integration

—

—

7

2

9

3

Workforce and lease termination

—

—

9

6

7

Acquisition related adjustments

—

—

3

—

4

—

—

Amortization of intangible assets

—

—

—

—

Levelized foreign currency translation

—

(1

)

—

—

—

—

—

—

Risk Management, as adjusted *

Corporate, as reported

1

)

)

)

)

)

)

Transaction-related costs

—

—

Legal, tax & benefit plan related

—

—

3

—

Clean energy-related

—

(5

)

—

(2

)

—

(2

)

—

)

Corporate, as adjusted *

1

)

)

)

)

)

)

Total Company, as reported

$

$

$

$

$

$

$

$

Total Company, as adjusted *

$

$

$

$

$

$

$

$

Total Brokerage & Risk Management, as reported

$

$

$

$

$

$

$

$

Total Brokerage & Risk Management, as adjusted *

$

$

$

$

$

$

$

$

*

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. A detailed

reconciliation of the 2025 and 2024 provision (benefit) for income taxes is shown on pages 14 and 15.

Brokerage Segment

Reported GAAP to Adjusted Non-GAAP Reconciliations (dollars in millions):

See “Information Regarding Non-GAAP Measures” on page 9 of 15.

Organic Revenues(Non-GAAP)

Base Commissions and Fees

Commissions and fees, as reported

$

$

$

$

Less commissions and fees from acquisitions, divested operations and other

)

)

)

)

Levelized foreign currency translation

—

—

Organic base commissions and fees

$

$

$

$

Organic change in base commissions and fees

4

%

6

%

Supplemental Revenues

Supplemental revenues, as reported

$

$

$

$

Less supplemental revenues from acquisitions, divested operations and other

)

—

)

—

Levelized foreign currency translation

—

1

—

3

Organic supplemental revenues

$

$

$

$

Organic change in supplemental revenues

%

%

Contingent Revenues

Contingent revenues, as reported

$

$

$

$

Less contingent revenues from acquisitions, divested operations and other

)

—

)

—

Levelized foreign currency translation

—

1

—

1

Organic contingent revenues

$

$

$

$

Organic change in contingent revenues

%

5

%

Total reported commissions, fees, supplemental revenues and contingent revenues

$

$

$

$

Less commissions, fees, supplemental revenues and contingent revenues from acquisitions, divested

operations and other

)

)

)

)

Levelized foreign currency translation

—

—

Total organic commissions, fees, supplemental revenues and contingent revenues

$

$

$

$

Total organic change

5

%

6

%

Acquisition Activity

Number of acquisitions closed *

6

Estimated annualized revenues acquired (in millions)

$

$

$

$

*

In the fourth quarter of 2025 Gallagher issued 6,000 shares of its common stock directly to sellers in

connection with tax-free exchange acquisitions. No shares were issued in fourth quarter 2024 in connection with tax-free exchange acquisitions.

Brokerage Segment Reported GAAP to Adjusted Non-GAAPReconciliations (continued) (dollars in millions):

See “Information Regarding Non-GAAP Measures” beginning on page 9 of 15.

Acquisition of AssuredPartners

As previously disclosed, on August 18, 2025, we acquired AssuredPartners for approximately $13.8 billion. 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 (collectively, 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.

Compensation Expense and Ratios

Compensation expense, as reported

$

$

$

$

Acquisition integration

)

)

)

)

Workforce and lease termination related charges

)

)

)

)

Acquisition related adjustments

)

)

)

)

Levelized foreign currency translation

—

—

Compensation expense, as adjusted

$

$

$

$

Reported compensation expense ratios using reported revenues on pages 1 and 2

*

%

%

%

%

Adjusted compensation expense ratios using adjusted revenues on pages 1 and 2

*

*

%

%

%

%

*

T4Reported fourth quarter 2025 compensation expense ratio was 2.8 pts higher than fourth quarter 2024. This ratio

was primarily impacted by higher integration and workforce termination costs, as well as the impact of recent acquisitions and . lower interest income revenues in the quarter, as fourth quarter 2024 included interest income earned on proceeds

associated with the AssuredPartners Financing in December 2024.

**

Adjusted fourth quarter 2025 compensation expense ratio was 0.4 pts higher than fourth quarter 2024. This ratio

was primarily impacted by recent acquisitions as well as lower interest income revenues in the quarter, as fourth quarter 2024 included interest income earned on proceeds associated with the AssuredPartners Financing in December 2024.

Operating Expense and Ratios

Operating expense, as reported

$

$

$

$

Acquisition integration

)

)

)

)

Workforce and lease termination related charges

(4

)

(4

)

)

)

Levelized foreign currency translation

—

8

—

Operating expense, as adjusted

$

$

$

$

Reported operating expense ratios using reported revenues on pages 1 and 2

*

%

%

%

%

Adjusted operating expense ratios using adjusted revenues on pages 1 and 2

*

*

%

%

%

%

*

Reported fourth quarter 2025 operating expense ratio was 1.6 pts higher than fourth quarter 2024. This ratio

was primarily impacted by higher integration and technology costs, partially offset by savings in professional fees. This ratio was also impacted by lower interest income revenues in the quarter, as fourth quarter 2024 included interest income

earned on proceeds associated with the AssuredPartners Financing in December 2024.

**

Adjusted fourth quarter 2025 operating expense ratio was 0.5 pts higher than fourth quarter 2024. This ratio

was primarily impacted by increased technology costs, partially offset by savings in professional fees. This ratio was also impacted by lower interest income revenues in the quarter, as fourth quarter 2024 included interest income earned on proceeds

associated with the AssuredPartners Financing in December 2024.

Brokerage Segment Reported GAAP to Adjusted Non-GAAPReconciliations (continued) (dollars in millions):

See “Information Regarding Non-GAAP Measures”

Net Earnings to Adjusted EBITDAC(Non-GAAP)

Net earnings, as reported

$

$

$

$

Provision for income taxes

Depreciation

Amortization

Change in estimated acquisition earnout payables

6

EBITDAC

Net losses (gains) on divestitures

)

1

)

)

Acquisition integration

Workforce and lease termination related charges

Acquisition related adjustments

Levelized foreign currency translation

—

8

—

EBITDAC, as adjusted

$

$

$

$

Net earnings margin, as reported using reported revenues on pages 1 and 2

*

%

%

%

%

EBITDAC margin, as adjusted using adjusted revenues on pages 1 and 2

*

%

%

%

%

*

Fourth quarter 2024 adjusted EBITDAC margin includes approximately $20 million of interest income revenues

earned on the proceeds received in December 2024 related to the AssuredPartners Financing. This interest income in the prior period, as well as the seasonality of AssuredPartners and the roll-in of tuck-in acquisitions, unfavorably impacted the year over year change in fourth quarter adjusted EBITDAC margin by approximately 1.3%.

Risk Management Segment Reported GAAP to Adjusted Non-GAAP Reconciliations (dollars in millions):

See “Information Regarding Non-GAAP Measures” on page 9 of 15.

Organic Revenues(Non-GAAP)

Fees

$

$

$

$

International performance bonus fees

5

3

8

Fees as reported

Less fees from acquisitions

)

—

)

—

Less divested operations

—

(2

)

—

(9

)

Levelized foreign currency translation

—

3

—

(1

)

Organic fees

$

$

$

$

Organic change in fees

7

%

6

%

Acquisition Activity

Number of acquisitions closed

1

1

2

2

Estimated annualized revenues acquired (in millions)

$

$

$

$

Risk Management Segment Reported GAAP to Adjusted Non-GAAPReconciliations (continued) (dollars in millions):

See “Information Regarding Non-GAAP Measures”

beginning on page 9 of 15.

Compensation Expense and Ratios

Compensation expense, as reported

$

$

$

$

Acquisition integration

(1

)

(1

)

(3

)

(2

)

Workforce and lease termination related charges

—

(1

)

(9

)

(4

)

Acquisition related adjustments

(2

)

—

(4

)

—

Levelized foreign currency translation

—

1

—

(2

)

Compensation expense, as adjusted

$

$

$

$

Reported compensation expense ratios using reported revenues (before reimbursements) on pages 1

and 2

*

%

%

%

%

Adjusted compensation expense ratios using adjusted revenues (before reimbursements) on pages 1

and 2

*

%

%

%

%

*

Reported fourth quarter 2025 compensation expense ratio was 0.2 pts higher than fourth quarter 2024. Adjusted

fourth quarter 2025 compensation ratio was 0.4 pts higher than fourth quarter 2024. Both ratios were primarily impacted by increased incentive compensation, partially offset by savings related to headcount controls.

Operating Expense and Ratios

Operating expense, as reported

$

$

$

$

Acquisition integration

(3

)

(1

)

(6

)

(1

)

Workforce and lease termination related charges

(1

)

(1

)

(3

)

(3

)

Levelized foreign currency translation

—

1

—

1

Operating expense, as adjusted

$

$

$

$

Reported operating expense ratios using reported revenues (before reimbursements) on pages 1 and

2

*

%

%

%

%

Adjusted operating expense ratios using reported revenues (before reimbursements) on pages 1 and

2

*

*

%

%

%

%

*

Reported fourth quarter 2025 operating expense ratio was 0.8 pts lower than fourth quarter 2024. This ratio was

primarily impacted by savings in client-related expenses and lower business insurance costs, partially offset by increased integration costs.

**

Adjusted fourth quarter 2025 operating expense ratio was 1.3 pts lower than fourth quarter 2024. This ratio was

primarily impacted by savings in client-related expenses and lower business insurance costs.

Net Earnings to Adjusted EBITDAC(Non-GAAP)

Net earnings, as reported

$

$

$

$

Provision for income taxes

Depreciation

Amortization

6

4

Change in estimated acquisition earnout payables

1

—

2

—

EBITDAC

Net (gains) on divestitures

(1

)

—

(2

)

—

Acquisition integration

2

2

9

3

Workforce and lease termination related charges

2

2

7

Acquisition related adjustments

3

—

4

—

Levelized foreign currency translation

—

1

—

—

EBITDAC, as adjusted

$

$

$

$

Net earnings margin, as reported using reported revenues (before reimbursements) on pages 1 and

2

%

%

%

%

EBITDAC margin, as adjusted using adjusted revenues (before reimbursements) on pages 1 and

2

%

%

%

%

Corporate Segment Reported GAAP to Adjusted Non-GAAP Reconciliation (dollars in millions):

See “Information Regarding Non-GAAP Measures” beginning on page 9 of 15.

4th Quarter

Pretax

Loss

Income

Tax

Benefit

Net Earnings

(Loss)

Attributable to

Controlling

Interests

Pretax

Loss

Income

Tax

Benefit

Net Earnings

(Loss)

Attributable to

Controlling

Interests

Components of Corporate Segment, as reported

Interest and banking costs

$

)

$

$

)

$

)

$

$

)

Clean energy related

(2

)

1

(1

)

—

—

—

Acquisition costs (1)

)

9

)

)

5

)

Corporate (2)

)

)

)

)

Reported 4th Quarter

)

)

)

)

Adjustments

Clean energy related

—

—

—

(2

)

—

(2

)

Transaction-related costs (1)

(9

)

(2

)

Legal and tax related (3)

(9

)

1

—

—

—

Benefit plan related (4)

)

—

—

—

Components of Corporate Segment, as adjusted

Interest and banking costs

)

)

)

)

Clean energy related

(2

)

1

(1

)

(2

)

—

(2

)

Acquisition costs

(5

)

—

(5

)

(7

)

3

(4

)

Corporate (2)

)

)

)

)

Adjusted 4th Quarter

$

)

$

$

)

$

)

$

$

)

Year Ended December 31,

Components of Corporate Segment, as reported

Interest and banking costs

$

)

$

$

)

$

)

$

$

)

Clean energy related

(8

)

3

(5

)

(6

)

1

(5

)

Acquisition costs (1)

)

)

)

)

Corporate (2)

)

)

)

)

Reported year

)

)

)

)

Adjustments

Clean energy related

—

—

—

(2

)

—

(2

)

Transaction-related costs (1)

)

(6

)

Legal and tax related (3)

)

9

—

3

3

Benefit plan related (4)

)

—

—

—

Components of Corporate Segment, as adjusted

Interest and banking costs

)

)

)

)

Clean energy related

(8

)

3

(5

)

(8

)

1

(7

)

Acquisition costs

)

2

)

)

4

)

Corporate (2)

)

)

)

)

Adjusted Year

$

)

$

$

)

$

)

$

$

)

(1)

Gallagher incurred transaction-related costs, which include legal, consulting, employee compensation and other

professional fees associated with completed, future and terminated acquisitions. Adjustments primarily relate to the acquisition of the Willis Towers Watson treaty reinsurance brokerage operations, the acquisitions of Buck, Cadence Insurance,

Eastern Insurance Group, all of which closed in 2023, as well as Woodruff Sawyer and AssuredPartners, which closed in April 2025 and August 2025, respectively.

(2)

Corporate pretax loss includes a net unrealized foreign exchange remeasurement loss of $(4) million in fourth

quarter 2025 and a net unrealized foreign exchange remeasurement gain of $16 million in fourth quarter 2024. Corporate pretax loss includes a net unrealized foreign exchange remeasurement loss of $(47) million in the year ended

December 31, 2025 and a net unrealized foreign exchange remeasurement loss of zero in the year ended December 31, 2024.

(3)

Adjustments in fourth quarter 2025 and 2024 include costs associated with legal and tax matters.

(4)

Adjustments in fourth quarter 2025 include costs associated with the termination of the Gallagher US defined

pension plan and other benefit plan changes.

Interest and banking costs and debt - At December 31, 2025, Gallagher

had $9,550 million of borrowings from public debt, $3,323 million of borrowings from private placements and no borrowings under its line of credit facility. In addition, Gallagher had $226 million outstanding under a revolving loan

facility that provides funding for premium finance receivables, which are fully collateralized by the underlying premiums held by insurance carriers, and as such are excluded from its debt covenant computations, as applicable. Interest and banking

costs in fourth quarter 2025 are higher than the same period in 2024 primarily due to the debt issuances that occurred in December 2024.

Clean energy

related - For 2025, this consists of operating results related to Gallagher’s investments in new clean energy projects, primarily fusion and carbon sequestration projects.

Acquisition costs - Consists mostly of external professional fees and other due diligence costs related to acquisitions. On occasion, Gallagher enters

into forward currency hedges for the purchase price of committed, but not yet funded, acquisitions with funding requirements in currencies other than the U.S. dollar. The gains or losses, if any, associated with these hedge transactions are also

included in acquisition costs.

Corporate - Consists of overhead allocations mostly related to corporate staff compensation, other corporate level

activities, and net unrealized foreign exchange remeasurement. In addition, it includes the tax expense related to the partial taxation of foreign earnings, nondeductible executive compensation and entertainment expenses, the tax benefit from the

vesting of employee equity awards, as well as other permanent or discrete tax items not reflected in the provision for income taxes in the Brokerage and Risk Management segments.

Income Taxes - Gallagher allocates the provision for income taxes to its Brokerage and Risk Management segments using the local country statutory

rates. Gallagher’s consolidated effective tax rate for the quarters ended December 31, 2025 and 2024 were 14.3% and 22.5%, respectively. Gallagher’s consolidated effective tax rate for the year ended December 31, 2025 and 2024

Webcast Conference Call - Gallagher will host a webcast conference call on Thursday, January 29, 2026 at

5:15 p.m. ET/4:15 p.m. CT. To listen to this call, please go to Arthur J. Gallagher & Co. - Events & Presentations (ajg.com). The call will be available for replay at such website for at least 90 days.

About Arthur J. Gallagher & Co.

Arthur J.

Gallagher & Co., a global insurance brokerage, risk management and consulting services firm, is headquartered in Rolling Meadows, Illinois. Gallagher provides these services in approximately 130 countries around the world through its owned

operations and a network of correspondent brokers and consultants.

Information Concerning Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. When used in

this press release, the words “anticipates,” “believes,” “contemplates,” “see,” “should,” “could,” “will,” “estimates,” “expects,”

“intends,” “plans” and variations thereof and similar expressions, are intended to identify forward-looking statements. Examples of forward-looking statements include, but are not limited to, anticipated future results or

performance of any segment or Gallagher as a whole; acquisition rollover revenues, statements regarding changes in its expenses in the next several quarters; future capital structure changes, including debt levels from time to time; the impact of

foreign currency on its results; integration costs; workforce and lease termination costs; amortization of intangibles; depreciation; change in estimated earnout payables; effective tax rate; earnings from continuing operations attributable to

noncontrolling interests; the premium rate environment and the state of insurance markets; and the economic environment.

Gallagher’s actual results

may differ materially from those contemplated by the forward-looking statements. Readers are therefore cautioned against relying on any of the forward-looking statements, which are neither statements of historical fact nor guarantees or assurances

of future performance.

Important factors that could cause actual results to differ materially from those in the forward-looking

statements include global economic and geopolitical events, including, among others, fluctuations in interest and inflation rates; T5geo-economic fragmentation and protectionism such as tariffs, trade wars or

similar governmental actions affecting the flows of goods, services or currency; a U.S. government shutdown; political violence and instability, such as the armed conflicts in Ukraine the Middle East, Latin America and the Caribbean; its actual

acquisition opportunities, including closing risks related to pending acquisitions, risks with respect to larger acquisitions such as AssuredPartners, the largest acquisition in our history, including risks related to its ability to successfully

integrate operations, the possibility that its assumptions may be inaccurate resulting in unforeseen obligations or liabilities and failure to realize the expected benefits of these acquisitions; damage to its reputation due to its failure to uphold

its culture or negative perceptions or publicity, including as a result of amplifying effects that the Internet and social media may have on such perceptions; reputational issues related to its sustainability-related activities, including potential

backlash against such activities, and compliance with increasingly complex climate- and other sustainability- related regulations, such as risks related to “greenwashing” and “greenhushing”; cybersecurity-related risks; T6its

ability to apply technology, data analytics and artificial intelligence effectively and potential increased costs resulting from such activities; risks associated with the use of artificial intelligence in its business operations, including

regulatory, data privacy, cybersecurity, errors and omissions, intellectual property and competition risks; heightened competition for talent and increased compensation costs; disasters or other business interruptions, including with respect to its

operations in India; risks related to its international operations, such as those related to regulatory, tax, sustainability, sanctions and anti-corruption compliance and increased scrutiny of the use ofoff-shore centers of excellence such as those we operate in India and elsewhere; changes to data privacy and protection laws and regulations; foreign exchange rates; changes in accounting standards; changes in

premium rates and in insurance markets generally, including the impact of large or man-made natural events; tax, environmental or other compliance risks related to its legacy clean energy investments; its

inability to receive dividends or other distributions from subsidiaries; and changes in the insurance brokerage industry’s competitive landscape.

Please refer to Gallagher’s filings with the Securities and Exchange Commission, including Item 1A, “Risk Factors,” of its Annual Report on

Form 10-K for the fiscal year ended December 31, 2024 and its subsequently filed Quarterly Reports on Form 10-Q for a more detailed discussion of these and other

factors that could impact its forward-looking statements. Any forward-looking statement made by Gallagher in this press release speaks only as of the date on which it is made. Except as required by applicable law, Gallagher does not undertake to

update the information included herein or the corresponding earnings release posted on Gallagher’s website.

Information Regarding Non-GAAP Measures

In addition to reporting financial results in accordance with GAAP, this press release provides

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 press release. Gallagher’s management believes that these

presentations provide useful information to management, analysts and investors regarding financial and business trends relating to Gallagher’s results of operations and financial condition or because they provide investors with measures that

its chief operating decision maker uses when reviewing Gallagher’s performance. See further below for definitions and additional reasons each of these measures is useful to investors. Gallagher’s 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 provided by Gallagher should be used in addition to, but not as a substitute for, the GAAP information provided. As disclosed in its most recent Proxy Statement, Gallagher makes

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 - Gallagher believes that the adjustednon-GAAP presentations of the current and prior period information presented in this earnings release provide stockholders and other interested persons with useful information regarding certain financial

metrics of Gallagher that may assist such persons in analyzing Gallagher’s operating results as they develop a future earnings outlook for Gallagher. The after-tax amounts related to the adjustments were

computed using the normalized effective tax rate for each respective period. See pages 14 and 15 for a reconciliation of the adjustments made to income taxes.

•

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 treaty reinsurance brokerage operations, Buck, Cadence Insurance, Eastern Insurance Group, My Plan Manager, Woodruff Sawyer and AssuredPartners), outside the scope of the usualtuck-in strategy, not expected to occur on an ongoing basis in the future once Gallagher fully assimilates 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 its IT related systems.

•

Transaction-related costs, which are associated with completed, future and terminated acquisitions. Costs

primarily relate to the acquisitions of the Willis Towers Watson treaty reinsurance brokerage operations, Buck, Cadence Insurance, Eastern Insurance Group, 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.

•

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-upsand other balance sheet adjustments made after the closing date; the net impact of these on first quarter 2024 results 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 Gallagher’s 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 fourth quarter 2025 and 2024 related to

costs associated with legal and tax matters.

•

Benefit plan related, which represents the impact of adjustments in fourth quarter 2025 related to costs

associated with the termination of the Gallagher US 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 Gallagher’s operating performance for the overall business and provide a meaningful way to measure its 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 Gallagher’s

operating performance and are also presented to improve the comparability of its 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, 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 Gallagher’s operating performance (and as such should not be used as a measure of Gallagher’s liquidity), and for the overall business is also presented to improve the comparability of its 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, excluding 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 period 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 Gallagher in both the current and prior period. In order to improve the comparability of Gallagher’s 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 revenue consists of fee revenues excluding the first twelve months of such revenues

generated from acquisitions and such revenues related to divested operations in each period presented. In order to improve the comparability of Gallagher’s 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, butnon-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. Gallagher has historically viewed organic revenue growth as an important indicator when assessing and evaluating the performance of its Brokerage and Risk Management segments. Gallagher also believes that using this non-GAAP measure allows readers of its financial statements to measure, analyze and compare the growth from its Brokerage and Risk Management segments in a meaningful and consistent manner.

Reconciliation of Non-GAAP Information Presented to GAAP Measures - This press release includes tabular

reconciliations to the most comparable GAAP measures, as follows: for EBITDAC (on pages 12 and 13), for adjusted revenues, adjusted EBITDAC and adjusted diluted net earnings per share (on pages 1 and 2), for organic revenue measures (on

pages 3 and 5, respectively, for the Brokerage and Risk Management segments), for adjusted compensation and operating expenses and adjusted EBITDAC margin (on pages 4, 5 and 6 respectively, for the Brokerage and Risk Management segments).

Arthur J. Gallagher & Co.

Reported Statement of Earnings and EBITDAC - 4th Quarter December 31,

(Unaudited - in millions except per share, percentage and workforce data)

Brokerage Segment

4th Q Ended

4th Q Ended

Year Ended

Year Ended

Commissions

$

$

$

$

Fees

Supplemental revenues

Contingent revenues

Interest income, premium finance revenues and other income

Total revenues

Compensation