AON US Equity☆

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

EXECUTIVE SUMMARY OF 2023 FINANCIAL RESULTS

Aon plc is a leading global professional services firm providing a broad range of risk and human capital solutions. Through our experience, global reach, and comprehensive analytics, we help clients meet rapidly changing, increasingly complex, and interconnected challenges related to risk and people. We are committed to accelerating innovation to address unmet and evolving client needs so that our clients are better informed, better advised, and able to make better decisions to protect and grow their business. Management remains focused on strengthening Aon and uniting the firm with one portfolio of capability enabled by data and analytics and one operating model to deliver additional insight, connectivity, and efficiency.

Financial Results

The following is a summary of our 2023 financial results:

•Revenue increased $897 million, or 7%, to $13.4 billion in 2023 compared to 2022, reflecting 7% organic revenue growth and a 2% favorable impact from fiduciary investment income, partially offset by a 2% unfavorable impact from acquisitions, divestitures and other.

•Operating expenses increased $781 million, or 9%, to $9.6 billion in 2023 compared to 2022 due primarily to an increase in expense associated with 7% organic revenue growth, investments in long-term growth, a $197 million charge in connection with certain accrued actual or anticipated legal settlement expenses, and $135 million of expenses related to the Accelerating Aon United Restructuring Program.

•Operating margin decreased to 28.3% in 2023 from 29.4% in 2022. The decrease was driven by an increase in operating expenses as listed above.

•Due to the factors set forth above, Net income was $2.6 billion in 2023, a decrease of $18 million, or 1%, from 2022.

•Diluted earnings per share increased 3% to $12.51 per share during the twelve months of 2023 compared to $12.14 per share for the prior year period.

•Cash flows provided by operating activities was $3.4 billion in 2023, an increase of $216 million, or 7%, from $3.2 billion in 2022, reflecting strong operating income growth and overall working capital optimization, partially offset by higher cash tax payments and a negative impact to working capital due to temporary invoicing delays associated with the implementation of a new system.

We focus on four key metrics not presented in accordance with U.S. GAAP that we communicate to shareholders: organic revenue growth, adjusted operating margin, adjusted diluted earnings per share, and free cash flow. These non-GAAP metrics should be viewed in addition to, not instead of, our Consolidated Financial Statements. The following is our measure of performance against these four metrics for 2023:

•Organic revenue growth, a non-GAAP measure defined under the caption “Review of Consolidated Results — Organic Revenue Growth,” was 7% in 2023, compared to 6% organic growth in the prior year period.

•Adjusted operating margin, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Operating Margin,” was 31.6% in 2023, compared to 30.8% in the prior year period. The increase in adjusted operating margin primarily reflects 7% organic revenue growth and higher fiduciary investment income, partially offset by increased expenses and investments in long-term growth.

•Adjusted diluted earnings per share, a non-GAAP measure defined under the caption “Review of Consolidated Results — Adjusted Diluted Earnings per Share,” was $14.14 per share in 2023, an increase of $0.75 per share, or 6%, from $13.39 per share in 2022. The increase in adjusted diluted earnings per share primarily reflects strong operational performance and effective capital management, highlighted by $2.7 billion of share repurchase during 2023.

•Free cash flow, a non-GAAP measure defined under the caption “Review of Consolidated Results — Free Cash Flow,” was $3.2 billion in 2023, an increase of $160 million, or 5%, from $3.0 billion in 2022, reflecting an increase in Cash flows from operations, partially offset by a $56 million increase in capital expenditures.

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ENVIRONMENTAL, SOCIAL, AND GOVERNANCE

For many companies, the management of ESG risks and opportunities has become increasingly important, and ESG-related challenges, such as extreme weather events, supply chain disruptions, cyber events, regulatory changes, ongoing public health impacts, and the increased focus on workforce resilience in various work environments, continue to create volatility and uncertainty for our clients. At Aon, helping clients manage risk - including ESG risk - is at the core of what we do. We offer a wide range of risk assessment, consulting, and advisory solutions, many of which are significant parts of our core business offerings, designed to address and manage ESG issues for clients, and to enable our clients to create more sustainable value. We see significant opportunity in enhancing our impact and delivering innovative client solutions on ESG matters.

DEFINITIVE ACQUISITION AGREEMENT

On December 19, 2023, Aon entered into a definitive agreement with NFP and the NFP seller, where Aon will acquire NFP for an aggregate purchase price of approximately $7 billion in cash and approximately 20,000,000 class A ordinary shares, nominal value of $0.01, in capital of Aon. The Company expects to fund the cash portion of the consideration with approximately $7 billion of new debt, with $5 billion raised in advance of the closing date and $2 billion raised at close of the acquisition. The acquisition is expected to be completed by mid-2024, subject to satisfaction or waiver of the closing conditions set forth in the Merger Agreement, including applicable regulatory approval.

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REVIEW OF CONSOLIDATED RESULTS

Summary of Results

Our consolidated results are as follow (in millions, except per share data):

Years Ended December 31

Revenue

Expenses

Amortization and impairment of intangible assets 89 113 147

Accelerating Aon United Program expenses 135 — —

Less: Net income attributable to noncontrolling interests 64 57 53

Net income attributable to Aon shareholders $ 2,564 $ 2,589 $ 1,255

Weighted average ordinary shares outstanding - diluted 205.0 213.2 226.1

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Consolidated Results for 2023 Compared to 2022

Revenue

Total revenue increased $897 million, or 7%, to $13.4 billion in 2023, compared to $12.5 billion in 2022. The increase was driven by 7% organic revenue growth and a 2% favorable impact from fiduciary investment income, partially offset by a 2% unfavorable impact from acquisitions, divestitures, and other.

Commercial Risk Solutions revenue increased $328 million, or 5%, to $7.0 billion in 2023, compared to $6.7 billion in 2022. Organic revenue growth was 5% in 2023, reflecting growth across all major geographies, driven by strong retention, management of the renewal book, and net new business generation. Growth in retail brokerage was highlighted by double-digit growth in Asia and the Pacific, driven by continued strength in core P&C. The U.S. grew modestly driven by strength in core areas of property, casualty, and construction, partially offset by the impact of external M&A and IPO activity. On average globally, exposures and pricing were positive, resulting in modestly positive market impact.

Reinsurance Solutions revenue increased $291 million, or 13%, to $2.5 billion in 2023, compared to $2.2 billion in 2022. Organic revenue growth was 10% in 2023 driven by strong retention and net new business generation, as well as strong growth in core Reinsurance. In addition, market impact was modestly positive overall.

Health Solutions revenue increased $209 million, or 9%, to $2.4 billion in 2023, compared to $2.2 billion in 2022. Organic revenue growth was 10% in 2023, reflecting strong growth globally in core health and benefits brokerage, driven by net new business generation and management of the renewal book. Strength in health and benefits included growth in advisory work related to wellbeing and resilience. Results also reflect double-digit growth in Consumer Benefits Solutions and strong growth in Talent.

Wealth Solutions revenue increased $64 million, or 5%, to $1.4 billion in 2023, compared to $1.4 billion in 2022. Organic revenue growth was 4% in 2023 reflecting growth in Retirement, driven by advisory demand and project-related work related to pension de-risking and ongoing impact of regulatory changes. In Investments, a decrease in AUM-based delegated investment management revenue due to debt and equity market movements was partially offset by higher advisory demand and project-related work.

Compensation and Benefits

Compensation and benefits increased $425 million, or 7%, in 2023 compared to 2022. The increase was primarily driven by an increase in expense associated with 7% organic revenue growth.

Information Technology

Information technology, which represents costs associated with supporting and maintaining our infrastructure, increased $25 million, or 5%, in 2023 compared to 2022. The increase was primarily driven by ongoing investments in Aon Business Services-enabled technology platforms and technology to drive long-term growth and continued investment in core infrastructure and security.

Premises

Premises, which represents the cost of occupying offices in various locations throughout the world, increased $5 million, or 2%, in 2023 compared to 2022.

Depreciation of Fixed Assets

Depreciation of fixed assets primarily relates to software, leasehold improvements, furniture, fixtures and equipment, computer equipment, buildings, and automobiles. Depreciation of fixed assets increased $16 million, or 11%, in 2023 compared to 2022, due primarily to ongoing investments in Aon Business Services-enabled technology platforms to drive long-term growth.

Amortization and Impairment of Intangible Assets

Amortization and impairment of intangibles primarily relates to finite-lived customer-related and contract-based, technology, and tradename assets. Amortization and impairment of intangibles decreased $24 million, or 21%, in 2023 compared to 2022 due primarily to a decrease associated with assets held for sale in 2023 as part of ongoing portfolio management and assets fully amortized in the prior year period.

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Other General Expense

Other general expenses increased $199 million, or 16%, in 2023 compared to 2022. The increase was due primarily to a $197 million charge in connection with certain accrued actual or anticipated legal settlement expenses.

Accelerating Aon United Program Expenses

Accelerating Aon United Program expenses were $135 million in 2023, reflecting restructuring charges associated with the Program announced in the third quarter of 2023, relating to workforce optimization, asset impairments, and technology and other costs.

Interest Income

Interest income represents income earned, net of expense, on operating cash balances and other income-producing investments. It does not include interest earned on funds held on behalf of clients. Interest income was $31 million in 2023, an increase of $13 million, or 72%, from 2022, reflecting higher interest rates.

Interest Expense

Interest expense, which represents the cost of our debt obligations, was $484 million in 2023, an increase of $78 million, or 19%, from 2022. The increase was driven primarily by an overall increase in total debt and higher interest rates.

Other Income (Expense)

Other expense was $163 million in 2023, which primarily reflects an expense from the unfavorable impact of exchange rates on the remeasurement of assets and liabilities in non-functional currencies and a non-cash net periodic pension cost. Other expense was $125 million in 2022, primarily reflecting a non-cash pension settlement charge of $170 million, partially offset by gains from sale of businesses.

Income before Income Taxes

Income before income taxes was flat at $3.2 billion in 2023, compared to the prior year period.

Income Taxes

The effective tax rate on net income was 17.1% in 2023 and 16.2% in 2022. The 2023 tax rate was primarily driven by the geographical distribution of income and certain discrete items, including the tax benefits associated with the release of a valuation allowance and share-based payments.

The 2022 tax rate was primarily driven by the geographical distribution of income and certain discrete items, primarily the favorable impacts of share-based payments.

Ireland, the U.K., and many E.U. member states, among others, have enacted legislation to implement the global minimum tax that are consistent with the OECD’s proposed Pillar Two tax regime. There remains significant uncertainty, however, as to how Ireland’s Pillar Two tax regime and the OECD’s past and potentially future Pillar Two guidance will ultimately apply to the Company. The Company is currently evaluating the potential impact that this may have on its global effective tax rate, results of operations, cash flows, and financial condition beginning in 2024.

Net Income Attributable to Aon Shareholders

Net income attributable to Aon shareholders decreased $25 million to $2.6 billion, or $12.51 per diluted share, in 2023, compared to $2.6 billion, or $12.14 per diluted share, in 2022.

Consolidated Results for 2022 Compared to 2021

We have elected not to include a discussion of our consolidated results for 2022 compared to 2021 in this report in reliance upon Instruction 1 to Item 303(b) of Regulation S-K. This discussion can be found in our Annual Report on Form 10-K for the year ended December 31, 2022, which was filed with the SEC on February 17, 2023.

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Non-GAAP Metrics

In our discussion of consolidated results, we sometimes refer to certain non-GAAP supplemental information derived from consolidated financial information specifically related to organic revenue growth, adjusted operating margin, adjusted diluted earnings per share, adjusted net income attributable to Aon shareholders, adjusted net income per share, other income (expense), as adjusted, adjusted effective tax rate, free cash flow, and the impact of foreign exchange rate fluctuations on operating results. Management believes that these measures provide helpful supplemental information that enables investors to make meaningful period-to-period comparisons. Management also uses these measures to assess operating performance and performance for compensation. This non-GAAP supplemental information should be viewed in addition to, not instead of, our Consolidated Financial Statements.

Organic Revenue Growth

We use supplemental information related to organic revenue growth to help us and our investors evaluate business growth from ongoing operations. Organic revenue growth is a non-GAAP measure that includes the impact of certain intercompany activity and excludes the impact of changes in foreign exchange rates, fiduciary investment income, acquisitions, divestitures (including held for sale disposal groups), transfers between revenue lines, and gains or losses on derivatives accounted for as hedges. This supplemental information related to organic revenue growth represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Consolidated Financial Statements. Industry peers provide similar supplemental information about their revenue performance, although they may not make identical adjustments. A reconciliation of this non-GAAP measure to the reported Total revenue is as follows (in millions, except percentages):

Years Ended

Revenue

Commercial Risk Solutions $ 7,043 $ 6,715 5 % — % 2 % (2) % 5 %

Elimination (12) (17) N/A N/A N/A N/A N/A

Years Ended

Revenue

Elimination (17) (19) N/A N/A N/A N/A N/A

(1)Currency impact represents the effect on prior year period results if they were translated at current period foreign exchange rates.

(2)Fiduciary investment income for the years ended December 31, 2023, 2022, and 2021 was $274 million, $76 million, and $8 million, respectively.

(3)Organic revenue growth includes the impact of certain intercompany activity and excludes the impact ofchanges in foreign exchange rates, fiduciary investment income, acquisitions, divestitures (including held for sale disposal groups, which had a 1% favorable impact on total organic revenue growth for the year-ended December 31, 2023), transfers between revenue lines, and gains or losses on derivatives accounted for as hedges.

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Adjusted Operating Margin

We use adjusted operating margin as a non-GAAP measure of core operating performance of the Company. Adjusted operating margin excludes the impact of certain items, as listed below, because management does not believe these expenses reflect our core operating performance. This supplemental information related to adjusted operating margin represents a measure not in accordance with U.S. GAAP, and should be viewed in addition to, not instead of, our Consolidated Financial Statements.

A reconciliation of this non-GAAP measure to reported operating margins is as follows (in millions, except percentages):

Years Ended December 31

Amortization and impairment of intangible assets 89 113

Accelerating Aon United Program expenses (1) 135 —

Transaction costs (3) 17 —

Operating income - as adjusted $ 4,223 $ 3,840

Operating margin - as adjusted 31.6 % 30.8 %

(1)Total charges related to the Program are expected to include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation costs.

(2)In the fourth quarter of 2023, Aon recognized actual and anticipated legal settlement expenses in connection with transactions for which capital was arranged by a third party, Vesttoo Ltd. primarily in the form of letters of credit from third party banks that are alleged to have been fraudulent. Certain actual or anticipated legal settlements expenses totaling $197 million have been recognized in the current period, where certain potentially meaningful amounts may be recoverable in future periods. Additionally, a $58 million charge was recognized in the second quarter of 2022 with certain other legal settlements reached in matters unrelated to Vesttoo.

(3)In the fourth quarter of 2023, we entered into a definitive agreement to acquire NFP. As part of the definitive agreement, certain transaction costs were incurred including advisory, legal, accounting, and other professional or consulting fees required to complete the acquisition.

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Adjusted Diluted Earnings per Share

We use adjusted diluted earnings per share as a non-GAAP measure of our core operating performance. Adjusted diluted earnings per share excludes the impact of certain items, as listed below, because management does not believe these expenses are the best indicators of our core operating performance. This supplemental information related to adjusted diluted earnings per share represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, our Consolidated Financial Statements.

A reconciliation of this non-GAAP measure to reported diluted earnings per share is as follows (in millions, except per share data and percentages):

U.S. GAAP Adjustments Non-GAAP Adjusted

Interest income 31 — 31

Less: Net income attributable to noncontrolling interests 64 — 64

Net income attributable to Aon shareholders $ 2,564 $ 335 $ 2,899

Weighted average ordinary shares outstanding — diluted 205.0 — 205.0

Effective tax rates (2) 17.1 % 18.5 %

U.S. GAAP Adjustments Non-GAAP Adjusted

Interest income 18 — 18

Less: Net income attributable to noncontrolling interests 57 — 57

Net income attributable to Aon shareholders $ 2,589 $ 266 $ 2,855

Weighted average ordinary shares outstanding — diluted 213.2 — 213.2

Effective tax rates (2) 16.2 % 16.7 %

(1)To further our pension de-risking strategy, we settled certain pension obligations in the Netherlands through the purchase of annuities, where certain pension assets were liquidated to purchase the annuities. A non-cash settlement charge totaling $27 million was recognized in the second quarter of 2023, which is excluded from Other income (expense) - as adjusted.

(2)Adjusted items are generally taxed at the estimated annual effective tax rate, except for the applicable tax impact associated with the anticipated sale of certain assets and liabilities classified as held for sale, certain pension and legal settlements, AAU Program expenses, and certain transaction costs and other charges related to the definitive agreement to acquire NFP, which are adjusted at the related jurisdictional rate.

(3)To further its pension de-risking strategy the Company purchased an annuity for portions of its U.S. pension plans that will settle certain obligations. A non-cash settlement charge totaling $170 million was recognized in the fourth quarter of 2022, which is excluded from Other income (expense) - as adjusted.

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Free Cash Flows

We use free cash flow, defined as cash flow provided by operations minus capital expenditures, as a non-GAAP measure of our core operating performance and cash generating capabilities of our business operations. This supplemental information related to free cash flow represents a measure not in accordance with U.S. GAAP and should be viewed in addition to, not instead of, the Consolidated Financial Statements. Management believes the supplemental information related to free cash flow is helpful to investors when evaluating our operating performance and liquidity results. The use of this non-GAAP measure does not imply or represent the residual cash flow for discretionary expenditures. A reconciliation of this non-GAAP measure to cash flow provided by operations is as follows (in millions):

Years Ended December 31

Cash provided by operating activities $ 3,435 $ 3,219

Capital expenditures (252) (196)

Impact of Foreign Currency Exchange Rate Fluctuations

Because we conduct business in more than 120 countries and sovereignties, foreign currency exchange rate fluctuations have a significant impact on our business. Foreign currency exchange rate movements may be significant and may distort true period-to-period comparisons of changes in revenue or pretax income. Therefore, to give financial statement users meaningful information about our operations, we have provided an illustration of the impact of foreign currency exchange rate fluctuations on our financial results. The methodology used to calculate this impact isolates the impact of the change in currencies between periods by translating the prior year’s revenue, expenses, and net income using the current year’s foreign currency exchange rates.

Currency fluctuations had an unfavorable impact of $0.17 on earnings per diluted share during the year ended December 31, 2023 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had an unfavorable impact of $0.33 on earnings per diluted share during the year ended December 31, 2022, if 2021 results were translated at 2022 rates.

Currency fluctuations had an unfavorable impact of$0.17 on adjusted earnings per diluted share during the year ended December 31, 2023 if prior year period results were translated at current period foreign exchange rates. Currency fluctuations had an unfavorable impact of $0.44 on adjusted earnings per diluted share during the year ended December 31, 2022, if 2021 results were translated at 2022 rates. These translations are performed for comparative and illustrative purposes only and do not impact the accounting policies or practices for amounts included in our Financial Statements.

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LIQUIDITY AND FINANCIAL CONDITION

Liquidity

Executive Summary

We believe that our balance sheet and strong cash flow provide us with adequate liquidity. Our primary sources of liquidity in the near-term include cash flows provided by operations and available cash reserves; primary sources of liquidity in the long-term include cash flows provided by operations, debt capacity available under our credit facilities, and capital markets. Our primary uses of liquidity are operating expenses and investments, capital expenditures, acquisitions, share repurchases, pension obligations, shareholder dividends, and Accelerating Aon United Program cash charges. We believe that cash flows from operations, available credit facilities, available cash reserves, and the capital markets will be sufficient to meet our liquidity needs, including cash requirements to close our acquisition of NFP, principal and interest payments on debt obligations, capital expenditures, pension contributions, and anticipated working capital requirements in the next twelve months and over the long-term.

Cash on our balance sheet includes funds available for general corporate purposes, as well as amounts restricted as to their use. Funds held on behalf of clients in a fiduciary capacity are segregated and shown together with uncollected insurance premiums and claims in Fiduciary assets in the Consolidated Statements of Financial Position, with a corresponding amount in Fiduciary liabilities.

In our capacity as an insurance broker or agent, we collect premiums from insureds and, after deducting our commission, remit the premiums to the respective insurance underwriters. We also collect claims or refunds from underwriters on behalf of insureds, which are then returned to the insureds. Unremitted insurance premiums and claims are held by us in a fiduciary capacity. The levels of funds held on behalf of clients and liabilities can fluctuate significantly depending on when we collect the premiums, claims, and refunds, make payments to underwriters and insureds, and collect funds from clients and make payments on their behalf, and upon the impact of foreign currency movements. Funds held on behalf of clients, because of their nature, are generally invested in highly liquid securities with highly rated, credit-worthy financial institutions. Fiduciary assets include funds held on behalf of clients comprised of cash and cash equivalents of $6.9 billion and $6.4 billion at December 31, 2023 and 2022, respectively, and fiduciary receivables of $9.4 billion and $9.5 billion at December 31, 2023 and 2022, respectively. While we earn investment income on the funds held in cash and money market funds, the funds cannot be used for general corporate purposes.

We maintain multi-currency cash pools with third-party banks in which various Aon entities participate. Individual Aon entities are permitted to overdraw on their individual accounts provided the overall global balance does not fall below zero. At December 31, 2023, non-U.S. cash balances of one or more entities may have been negative; however, the overall balance was positive.

The following table summarizes our Cash and cash equivalents, Short-term investments, and Fiduciary assets as of December 31, 2023 (in millions):

Statement of Financial Position Classification

Asset Type Cash and cashequivalents Short-terminvestments Fiduciaryassets Total

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Cash and cash equivalents and funds held on behalf of clients, including $43 million of cash and cash equivalents and funds held on behalf of clients classified as held for sale, increased $646 million in 2023 compared to 2022. A summary of our cash flows provided by and used for operating, investing, and financing activities is as follows (in millions):

Years Ended December 31

Cash provided by operating activities $ 3,435 $ 3,219

Cash provided by (used for) investing activities $ (188) $ (449)

Cash used for financing activities $ (2,865) $ (1,790)

Operating Activities

Net cash provided by operating activities during the year ended December 31, 2023 were $3.4 billion, an increase of $216 million compared to $3.2 billion of Cash flows provided by operating activities in the prior year. This amount represents Net income reported, generally adjusted for gains from sales of businesses, losses from sales of businesses, share-based compensation expense, depreciation expense, amortization and impairments, and other non-cash income and expenses, including pension settlement charges. Adjustments also include changes in working capital, that relate primarily to the timing of payments of accounts payable and accrued liabilities, collection of receivables, and payments for Accelerating Aon United Program expenses.

Pension Contributions

Pension contributions were $50 million for the year ended December 31, 2023, as compared to $59 million for the year ended December 31, 2022. In 2024, we expect to contribute approximately $68 million in cash to our pension plans, including contributions to non-U.S. pension plans, which are subject to changes in foreign exchange rates.

Accelerating Aon United Program Expenses

In the third quarter of 2023, we initiated the Accelerating Aon United Program (the “Program”) with the purpose of streamlining our technology infrastructure, optimizing our leadership structure and resource alignment, and reducing the real estate footprint to align to our hybrid working strategy. The Program will include technology-related costs to facilitate streamlining and simplifying operations, headcount reduction costs, and costs associated with asset impairments, including real estate consolidation costs.

Program charges are recognized within Accelerating Aon United Program expenses on the accompanying Consolidated Statements of Income and consists of the following cost activities:

•Technology and other – includes costs associated with actions taken to rationalize applications, such as contract termination fees and other non-capitalizable costs associated with Program initiatives, which include professional service fees.

•Workforce optimization – includes costs associated with headcount reduction and other separation-related costs.

•Asset impairments – includes costs associated with impairment of assets, as they are identified, including ROU lease assets, leasehold improvements, and other capitalized assets no longer providing economic benefit.

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The changes in the Company’s liabilities for the Program as of December 31, 2023 are as follows (in millions):

Technology and other Workforce optimization Asset impairments Total

Liability Balance as of January 1, 2023 $ — $ — $ — $ —

Cash payments — (13) — (13)

Foreign currency translation and other — 1 — 1

Non-cash charges — (5) (18) (23)

Total costs incurred from inception to date $ 14 $ 103 $ 18 $ 135

The Program is currently expected to result in cumulative costs of approximately $1,000 million, consisting of approximately $900 million of cash charges and approximately $100 million of non-cash charges. The Program is estimated to generate annualized expense savings of approximately $350 million by the end of 2026, largely benefiting Compensation and benefits, Information technology, and Premises on the Consolidated Statements of Income. For the year ended December 31, 2023, total Program costs incurred were $135 million. The Company expects to continue to review the implementation of elements of the Program throughout the course of the Program and, therefore, there may be changes to expected timing, estimates of expected costs and related savings. We estimate that expense savings resulting from Program actions taken in 2023 will begin to be realized in 2024, predominately in Compensation and benefits on the Consolidated Statements of Income.

Investing Activities

Cash flows used for investing activities during the year ended December 31, 2023 were $188 million, a decrease of $261 million compared to $449 million of Cash flows used for investing activities in the prior year. Generally, the primary drivers of cash flows used for investing activities are acquisition of businesses, purchases of short-term investments, capital expenditures, and payments for investments. Generally, the primary drivers of cash flows provided by investing activities are sales of businesses, sales of short-term investments, and proceeds from investments. The gains and losses corresponding to cash flows provided by proceeds from investments and used for payments for investments are primarily recognized in Other income (expense) in the Consolidated Statements of Income.

Short-term Investments

Short-term investments decreased $83 million to $369 million at December 31, 2023 as compared to December 31, 2022. As disclosed in Note 15 “Fair Value Measurements and Financial Instruments” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report, the majority of our investments carried at fair value are money market funds. These money market funds are held throughout the world with various financial institutions. We are not aware of any market liquidity issues that would materially impact the fair value of these investments.

Acquisitions and Dispositions of Businesses

During 2023, the Company completed the acquisition of three businesses. Cash consideration, net of cash and funds held on behalf of clients acquired, was $35 million, which includes $2 million related to acquisitions completed in 2022. During 2023, the Company completed the disposition of two businesses for a $5 million cash inflow, net of cash and funds held on behalf of clients.

During 2022, the Company completed the acquisition of five businesses for consideration of $162 million, net of cash and funds held on behalf of clients, and the disposition of three businesses for an $81 million cash inflow, net of cash and funds held on behalf of clients.

Capital Expenditures

The Company’s additions to fixed assets including capitalized software, which amounted to $252 million in 2023 and $196 million in 2022, primarily related to the refurbishing and modernizing of office facilities, software development costs, and computer equipment purchases. In the current period, we continue to support certain technology projects to drive long-term growth and real estate projects to align with our Smart Working strategy.

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Financing Activities

Cash flows used for financing activities during the year ended December 31, 2023 were $2.9 billion, an increase of $1.1 billion compared to $1.8 billion of Cash flows used for financing activities in the prior year. Generally, the primary drivers of cash flow used for financing activities are repayments of debt, share repurchases, cash paid for employee taxes on withholding shares, dividends paid to shareholders, transactions with noncontrolling interests, and other financing activities, such as collection of or payments for deferred consideration in connection with prior year business acquisitions and divestitures. Generally, the primary drivers of cash flow provided by financing activities are issuances of debt, changes in net fiduciary liabilities, and proceeds from issuance of shares.

Share Repurchase Program

We have a share repurchase program authorized by our Board of Directors. The Repurchase Program was established in April 2012 with $5.0 billion in authorized repurchases, and was increased by $5.0 billion in authorized repurchases in each of November 2014, June 2017, and November 2020, and by $7.5 billion in February 2022 for a total of $27.5 billion in repurchase authorizations.

The following table summarizes the Company’s Share Repurchase activity (in millions, except per share data):

Years Ended December 31

Shares repurchased 8.4 11.1

Repurchase costs recorded to Accumulated deficit $ 2,700 $ 3,203

At December 31, 2023, the remaining authorized amount for share repurchase under the Repurchase Program was approximately $3.3 billion. Under the Repurchase Program, we have repurchased a total of 169.1 million shares for an aggregate cost of approximately $24.2 billion.

Borrowings

Total debt at December 31, 2023 was $11.2 billion, an increase of $0.4 billion compared to December 31, 2022.

In November 2023, Aon Global Limited’s $350 million 4.00% Senior Notes matured and were repaid in full.

In June 2023, Aon Global Limited’s $600 million 3.50% Senior Notes due June 2024 were classified as Short-term debt and current portion of long-term debt in the Consolidated Statement of Financial Position as the date of maturity is in less than one year.

On February 28, 2023, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company formed under the laws of England and Wales, both wholly owned subsidiaries of the Company, co-issued $750 million 5.35% Senior Notes due in February 2033. The Company intends to use the net proceeds from the offering for general corporate purposes.

In November 2022, Aon Corporation’s $500 million 2.20% Senior Notes matured and were repaid in full.

On September 12, 2022, Aon Corporation, a Delaware corporation, and Aon Global Holdings plc, a public limited company formed under the laws of England and Wales, both wholly owned subsidiaries of the Company, co-issued $500 million of 5.00% Senior Notes due September 2032. The Company intends to use the net proceeds from the offering for general corporate purposes.

On February 28, 2022, Aon Corporation and Aon Global Holdings plc co-issued $600 million of 2.85% Senior Notes due May 2027 and $900 million of 3.90% Senior Notes due February 2052. The Company intends to use the net proceeds from the offering for general corporate purposes.

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Aon Corporation has established a U.S. commercial paper program (the “U.S. Program”) and Aon Global Holdings plc has established a European multi-currency commercial paper program (the “European Program” and, together with the U.S. Program, the “Commercial Paper Programs”). On December 7, 2023, the Company entered into an agreement increasing the aggregate capacity under the U.S. Program by $250 million. Accordingly, commercial paper may be issued in aggregate principal amounts of up to approximately $1.3 billion under the U.S. Program and €625 million ($690 million at December 31, 2023 exchange rates) under the European Program, not to exceed the amount of our committed credit facilities, which was $2.0 billion at December 31, 2023. The aggregate capacity of the Commercial Paper Programs remain fully backed by our committed credit facilities. Commercial paper activity during the years ended December 31, 2023 and 2022 is as follows (in millions):

Years Ended December 31

Net issuances (repayments) $ (27) $ (65)

(1) The proceeds of the commercial paper issuances were used primarily for short-term working capital needs.

Other Liquidity Matters

Distributable Profits

We are required under Irish law to have available “distributable profits” to make share repurchases or pay dividends to shareholders. Distributable profits are created through the earnings of the Irish parent company and, among other methods, through intercompany dividends or a reduction in share capital approved by the High Court of Ireland. Distributable profits are not linked to a U.S. GAAP reported amount (e.g. Accumulated deficit). As of December 31, 2023 and December 31, 2022, we had distributable profits in excess of $27.5 billion and $29.0 billion, respectively. We believe that we will have sufficient distributable profits for the foreseeable future.

Revolving Credit Facilities

We expect cash generated by operations for 2023 to be sufficient to service our debt and contractual obligations, finance capital expenditures, and continue to pay dividends to our shareholders. Although cash from operations is expected to be sufficient to service these activities, we have the ability to access the commercial paper markets or borrow under our credit facilities to accommodate any timing differences in cash flows. Additionally, under current market conditions, we believe that we could access capital markets to obtain debt financing for longer-term funding, if needed.

As of December 31, 2023, we had two primary committed credit facilities outstanding: our $1.0 billion multi-currency U.S. credit facility expiring in September 2027 and our $1.0 billion multi-currency U.S. credit facility expiring in October 2028. In aggregate, these two facilities provide $2.0 billion in available credit.

Each of these primary committed credit facilities includes customary representations, warranties, and covenants, including financial covenants that require us to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to consolidated adjusted EBITDA, in each case, tested quarterly. At December 31, 2023, we did not have borrowings under either facility, and we were in compliance with the financial covenants and all other covenants contained therein during the rolling year ended December 31, 2023.

Subsequent Events

On February 16, 2024, we entered into a credit agreement in which lenders committed to provide a $2.0 billion unsecured term loan facility to Aon North America, Inc. Proceeds will be used to fund, in part, the acquisition of NFP, including the repayment of certain debt of NFP and portions of the related fees and expenses. The borrowings must be made in a single drawing on the closing date of the acquisition.

Shelf Registration Statement

On June 22, 2023, we filed a shelf registration statement with the SEC, registering the offer and sale from time to time of an indeterminate amount of, among other securities, debt securities, preference shares, class A ordinary shares and convertible securities. Our ability to access the market as a source of liquidity is dependent on investor demand, market conditions, and other factors.

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Rating Agency Ratings

The major rating agencies’ ratings of our debt at February 16, 2024 appear in the table below.

Ratings

Senior Long-term Debt Commercial Paper Outlook

Standard & Poor’s A- A-2 Negative

Moody’s Investor Services Baa2 P-2 Stable

Fitch, Inc. BBB+ F-2 Negative

In the fourth quarter of 2023, S&P’s Global Ratings downgraded our 'A-’ outlook to Negative, as compared to a Stable outlook, Moody’s Investor Services downgraded our ‘Baa2’ outlook to Stable, as compared to a Positive outlook, and Fitch,Inc. downgraded our ‘BBB+’ outlook to Negative, as compared to a Stable outlook at October 27, 2023 as reported in our Quarterly Report on Form 10-Q for the three months ended September 30, 2023.

Letters of Credit and Other Guarantees

We have entered into a number of arrangements whereby our performance on certain obligations is guaranteed by a third party through the issuance of an LOC. We had total LOCs outstanding of approximately $86 million at December 31, 2023, compared to $74 million at December 31, 2022. These LOCs cover the beneficiaries related to certain of our U.S. and Canadian non-qualified pension plan schemes and secure deductible retentions for our own workers’ compensation program. We also have obtained LOCs to cover contingent payments for taxes and other business obligations to third parties, and other guarantees for miscellaneous purposes at our international subsidiaries.

We have certain contractual contingent guarantees for premium payments owed by clients to certain insurance companies. The maximum exposure with respect to such contractual contingent guarantees was approximately $194 million at December 31, 2023, compared to $173 million at December 31, 2022.

Contractual Obligations

Our contractual obligations and commitments as of December 31, 2023 are comprised of principal payments on debt, interest payments on debt, operating leases, pension and other postretirement benefit plans, and purchase obligations.

Operating leases are primarily comprised of leased office space throughout the world. As leases expire, we do not anticipate difficulty in negotiating renewals or finding other satisfactory space if the premise becomes unavailable. In certain circumstances, we may have unused space and may seek to sublet such space to third parties, depending upon the demands for office space in the locations involved. Refer to Note 9 “Lease Commitments” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report for further information.

Pension and other postretirement benefit plan obligations include estimates of our minimum funding requirements pursuant to the ERISA and other regulations, as well as minimum funding requirements agreed with the trustees of our U.K. pension plans. Additional amounts may be agreed to with, or required by, the U.K. pension plan trustees. Nonqualified pension and other postretirement benefit obligations are based on estimated future benefit payments. We may make additional discretionary contributions. Refer to Note 12 “Employee Benefits” of the Notes to Consolidated Financial Statements contained in Part II, Item 8 of this report for further information.

Purchase obligations are defined as agreements to purchase goods and services that are enforceable and legally binding on us, and that specifies all significant terms, including the goods to be purchased or services to be rendered, the price at which the goods or services are to be rendered, and the timing of the transactions. Most of our purchase obligations are related to purchases of information technology services or other service contracts.

We had no other cash requirements from known contractual obligations and commitments that have, or are reasonably likely to have, a current or future material effect on the Company’s financial condition, results of operations, or liquidity.

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Guarantee of Registered Securities

Newly issued and outstanding debt securities by Aon Corporation are guaranteed by Aon Global Limited, Aon plc, Aon North America, Inc., and Aon Global Holdings plc, and include the following (collectively, the “Aon Corporation Notes”):

Aon Corporation Notes

8.205% Junior Subordinated Notes due January 2027

4.50% Senior Notes due December 2028

6.25% Senior Notes due September 2040

All guarantees of Aon plc, Aon Global Limited, Aon North America, Inc., and Aon Global Holdings plc of the Aon Corporation Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of Aon Corporation. There are no subsidiaries other than those listed above that guarantee the Aon Corporation Notes.

Newly issued and outstanding debt securities by Aon Global Limited are guaranteed by Aon plc, Aon Global Holdings plc, Aon North America, Inc., and Aon Corporation, and include the following (collectively, the “Aon Global Limited Notes”):

Aon Global Limited Notes

4.25% Senior Notes due December 2042

All guarantees of Aon plc, Aon Global Holdings plc, Aon North America, Inc., and Aon Corporation of the Aon Global Limited Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of Aon Global Limited. There are no subsidiaries other than those listed above that guarantee the Aon Global Limited Notes.

Newly co-issued and outstanding debt securities by Aon Corporation and Aon Global Holdings plc (together, the “Co-Issuers”) are guaranteed by Aon plc, Aon North America, Inc., and Aon Global Limited and include the following (collectively, the “Co-Issued Notes”):

Co-Issued Notes - Aon Corporation and Aon Global Holdings plc

2.60% Senior Notes due December 2031

5.00% Senior Notes due September 2032

5.35% Senior Notes due February 2033

3.90% Senior Notes due February 2052

All guarantees of Aon plc, Aon Global Limited, and Aon North America, Inc. of the Co-Issued Notes are joint and several as well as full and unconditional. Senior Notes rank pari passu in right of payment with all other present and future unsecured debt which is not expressed to be subordinate or junior in rank to any other unsecured debt of the Co-Issuers. There are no subsidiaries other than those listed above that guarantee the Co-Issued Notes.

Aon Corporation, Aon North America, Inc., Aon Global Limited, and Aon Global Holdings plc are indirect wholly owned subsidiaries of Aon plc. Aon plc, Aon Global Limited, Aon Global Holdings plc, Aon North America, Inc., and Aon

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Corporation together comprise the revised “Obligor group”. The following tables set forth summarized financial information for the revised Obligor group, which reflects the financial results of Aon North America, Inc. for the year ended December 31, 2023.

Adjustments are made to the tables to eliminate intercompany balances and transactions between the revised Obligor group. Intercompany balances and transactions between the revised Obligor group and non-guarantor subsidiaries are presented as separate line items within the summarized financial information. These balances are presented on a net presentation basis, rather than a gross basis, as this better reflects the nature of the intercompany positions and presents the funding or funded position that is to be received or owed. No balances or transactions of non-guarantor subsidiaries are presented in the summarized financial information, including investments of the revised Obligor group in non-guarantor subsidiaries.

Summarized Statement of Income information for the Obligor group is as follows (in millions):

Obligor Group

Summarized Statement of Income Information

Revenue $ —

Operating loss $ (127)

Expense from non-guarantor subsidiaries before income taxes $ (625)

Net loss attributable to Aon shareholders $ (1,285)

Summarized Statement of Financial Position information for the Obligor group is as follows (in millions):

Obligor Group

Summarized Statement of Financial Position Information

Receivables due from non-guarantor subsidiaries $ 1,431

Other current assets 230

Total current assets $ 1,661

Non-current receivables due from non-guarantor subsidiaries $ 10,873

Other non-current assets 1,228

Total non-current assets $ 12,101

Payables to non-guarantor subsidiaries $ 3,750

Other current liabilities 4,987

Total current liabilities $ 8,737

Non-current payables to non-guarantor subsidiaries $ 10,933

Other non-current liabilities 11,447

Total non-current liabilities $ 22,380

CRITICAL ACCOUNTING POLICIES AND ESTIMATES

The Consolidated Financial Statements have been prepared in accordance with U.S. GAAP. To prepare these financial statements, we make estimates, assumptions, and judgments that affect what we report as our assets and liabilities, what we disclose as contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of revenues and expenses during the periods presented.

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In accordance with our policies, we regularly evaluate our estimates, assumptions, and judgments, including, but not limited to, those concerning revenue recognition, pensions, goodwill and other intangible assets, contingencies, share-based payments, income taxes, and restructuring, and base our estimates, assumptions, and judgments on our historical experience and on factors we believe reasonable under the circumstances. The results involve judgments about the carrying values of assets and liabilities not readily apparent from other sources. If our assumptions or conditions change, the actual results we report may differ from these estimates. We believe the following critical accounting policies affect the more significant estimates, assumptions, and judgments we use to prepare these Consolidated Financial Statements.

Revenue Recognition

We recognize revenue when control of the promised services is transferred to the customer in the amount that best reflects the consideration to which we expect to be entitled in exchange for those services. For arrangements where control is transferred over time, an input or output method is applied that represents a faithful depiction of the progress towards completion of the performance obligation. For arrangements that include variable consideration, we assesses whether any amounts should be constrained. For arrangements that include multiple performance obligations, we allocate consideration based on their relative fair values.

Costs incurred in obtaining a contract are capitalized and amortized on a systematic basis that is consistent with the transfer of control of the services to which the asset relates, considering anticipated renewals when applicable. Certain contract-related costs, including pre-placement brokerage costs, are capitalized as a cost to fulfill and are amortized on a systematic basis consistent with the transfer of control of the services to which the asset relates, which is generally less than one year.

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. Revenue primarily includes insurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue is recorded net of allowances for estimated policy cancellations, which are determined based on an evaluation of historical and current cancellation data. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Commissions and fees for brokerage services may be invoiced near the effective date of the underlying policy or over the term of the arrangement in installments during the policy period.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, Strategy and Technology Group, and capital markets. Revenue primarily includes reinsurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Commissions and fees for brokerage services may be invoiced at the inception of the reinsurance period for certain reinsurance brokerage, or more commonly for treaty reinsurance arrangements, over the term of the arrangement in installments based on deposit or minimum premiums.

Health Solutions includes consulting and brokerage, Talent, and Consumer Benefits Solutions. Revenue primarily includes insurance commissions and fees for services rendered. For brokerage commissions, revenue is predominantly recognized at the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using input or output methods to depict the transfer of control of the services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those services. For arrangements recognized over time, various input or output measures, including units delivered or time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. For Talent, revenue is recognized over time or at a point in time upon completion of the services. For arrangements recognized over time, revenue is based on a measure of progress that depicts the transfer of control of the services to the customer utilizing an appropriate input or output measure to provide a faithful depiction of the progress towards completion of the performance obligation, including units delivered or time elapsed. Input and output measures utilized vary based on the arrangement but typically include reports provided or days elapsed. Revenue from Consumer Benefits Solutions arrangements are typically recognized upon successful enrollment of participants. Commissions and fees for brokerage services may be invoiced at the effective date of the underlying policy or over the term of the arrangement in installments during the policy period. Payment terms for other services vary but are typically over the contract term in installments.

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Wealth Solutions includes retirement consulting, pension administration and investments. Revenue recognized for these arrangements is predominantly recognized over the term of the arrangement using input or output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those services. For consulting arrangements recognized over time, revenue will be recognized based on a measure of progress that depicts the transfer of control of the services to the customer, utilizing an appropriate input or output measure to provide a reasonable assessment of the progress towards completion of the performance obligation including units delivered or time elapsed. Fees paid by customers for consulting services are typically charged on an hourly, project or fixed-fee basis, and revenue for these arrangements is typically recognized based on time incurred, days elapsed, or reports delivered. Revenue from time-and-materials or cost-plus arrangements are recognized as services are performed using input or output measures to provide a reasonable assessment of the progress towards completion of the performance obligation including hours worked, and revenue for these arrangements is typically recognized based on time and materials incurred. Revenue generated from our delegated investment business is generally earned as an agreed percentage based on AUM and, to a lesser extent, based on performance fees. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Payment terms vary but are typically over the contract term in installments.

Pensions

We sponsor defined benefit pension plans throughout the world. Our most significant plans are located in the U.S., the U.K., the Netherlands, and Canada, which are closed to new entrants. We have ceased crediting future benefits relating to salary and services for our U.S., U.K., Netherlands, and Canada plans to the extent statutorily permitted.

The service cost component of net periodic benefit cost is reported in Compensation and benefits and all other components are reported in Other income (expense). We used a full-yield curve approach in the estimation of the service and interest cost components of net periodic pension and postretirement benefit cost for our major pension and other postretirement benefit plans; this was obtained by applying the specific spot rates along the yield curve used in the determination of the benefit obligation to the relevant projected cash flows.

Recognition of Gains and Losses and Prior Service

Certain changes in the value of the obligation and in the value of plan assets, which may occur due to various factors such as changes in the discount rate and actuarial assumptions, actual demographic experience, and/or plan asset performance are not immediately recognized in net income. Such changes are recognized in Other comprehensive income and are amortized into net income as part of the net periodic benefit cost.

Unrecognized gains and losses that have been deferred in Other comprehensive income, as previously described, are amortized into expense as a component of periodic pension expense based on the average life expectancy of the U.S., U.K., Netherlands, and Canada plan members. We amortize any prior service expense or credits that arise as a result of plan changes over a period consistent with the amortization of gains and losses.

As of December 31, 2023, our pension plans have deferred losses that have not yet been recognized through income in the Consolidated Financial Statements. We amortize unrecognized actuarial losses outside of a corridor, which is defined as 10% of the greater of market-related value of plan assets or PBO. To the extent not offset by future gains, incremental amortization as calculated above will continue to affect future pension expense similarly until fully amortized.

The following table discloses our accumulated other comprehensive loss, the number of years over which we are amortizing the loss, and the estimated 2024 amortization of loss by country (in millions, except amortization period):

U.K. U.S. Other

Accumulated other comprehensive loss $ 1,909 $ 1,319 $ 431

Amortization period 6 to 24 years 6 to 24 years 11 to 33 years

The U.S. had no unrecognized prior service cost (credit) at December 31, 2023. The unrecognized prior service cost (credit) at December 31, 2023 was $39 million, and $(5) million for the U.K. and other plans, respectively.

For the U.S. pension plans, we use a market-related valuation of assets approach to determine the expected return on assets, which is a component of net periodic benefit cost recognized in the Consolidated Statements of Income. This approach recognizes 20% of any gains or losses in the current year’s value of market-related assets, with the remaining 80% spread over the next four years. As this approach recognizes gains or losses over a five-year period, the future value of assets and therefore, our net periodic benefit cost will be impacted as previously deferred gains or losses are recorded. As of December 31, 2023, the market-related value of assets was $1.8 billion. We do not use the market-related valuation approach to determine the funded status of the U.S. plans recorded in the Consolidated Statements of Financial Position. Instead, we record and present the

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funded status in the Consolidated Statements of Financial Position based on the fair value of the plan assets. As of December 31, 2023, the fair value of plan assets was $1.5 billion. Our non-U.S. plans use fair value to determine expected return on assets.

Rate of Return on Plan Assets and Asset Allocation

The following table summarizes the expected long-term rate of return on plan assets for future pension expense as of December 31, 2023:

U.K. U.S. Other

In determining the expected rate of return for the plan assets, we analyze investment community forecasts and current market conditions to develop expected returns for each of the asset classes used by the plans. In particular, we surveyed multiple third-party financial institutions and consultants to obtain long-term expected returns on each asset class, considered historical performance data by asset class over long periods, and weighted the expected returns for each asset class by target asset allocations of the plans.

The U.S. pension plan asset allocation is based on approved allocations following adopted investment guidelines. The investment policy for U.K. and other non-U.S. pension plans is generally determined by the plans’ trustees. Because there are several pension plans maintained in the U.K. and other non-U.S. categories, our target allocation presents a range of the target allocation of each plan. Target allocations are subject to change.

Impact of Changing Economic Assumptions

Changes in the discount rate and expected return on assets can have a material impact on pension obligations and pension expense.

Holding all other assumptions constant, the following table reflects what a 25 BPS increase and decrease in our discount rate would have on our PBO at December 31, 2023 (in millions):

Increase Decrease

U.K. plans $ (94) $ 97

U.S. plans $ (53) $ 55

Other plans $ (40) $ 42

(1)Increases to the PBO reflect increases to our pension obligations, while decreases in the PBO are recoveries toward fully-funded status. A change in the discount rate has an inverse relationship to the PBO.

Holding all other assumptions constant, the following table reflects what a 25 BPS increase and decrease in our discount rate would have on our estimated 2024 pension expense (in millions):

25 BPS Change in Discount Rate

Increase (decrease) in expense Increase Decrease

U.K. plans $ (2) $ 2

U.S. plans $ — $ (1)

Other plans $ — $ —

Holding all other assumptions constant, the following table reflects what a 25 BPS increase and decrease in our long-term rate of return on plan assets would have on our estimated 2024 pension expense (in millions):

25 BPS Change in Long-Term Rate of Return on Plan Assets

Increase (decrease) in expense Increase Decrease

U.K. plans $ (9) $ 9

U.S. plans $ (4) $ 4

Other plans $ (3) $ 3

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Estimated Future Contributions

We estimate cash contributions of approximately $68 million to our pension plans in 2024 as compared with cash contributions of $50 million in 2023.

Goodwill and Other Intangible Assets

Goodwill represents the excess of purchase price over the fair market value of the net assets acquired. We classify our intangible assets acquired as either customer-related and contract-based, technology, tradenames or other intangibles.

Goodwill is not amortized, but rather tested for impairment at least annually in the fourth quarter. We test more frequently if there are indicators of impairment or whenever business circumstances suggest that the carrying value of goodwill may not be recoverable. These indicators may include a sustained significant decline in our share price and market capitalization, a significant decline in our expected future cash flows, or a significant adverse change in legal factors or in the business climate, among others.

We perform impairment reviews at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment (referred to as a “component”). A component of an operating segment is a reporting unit if the component constitutes a business for which discrete financial information is available and segment management regularly reviews the operating results of that component. An operating segment shall be deemed to be a reporting unit if all of its components are similar, if none of its components are a reporting unit, or if the segment comprises only a single component. We aggregate components of any operating segments that have similar economic characteristics into a single reporting unit.

When evaluating these assets for impairment, we may first perform a qualitative assessment to determine whether it is more likely than not that a reporting unit is impaired. If we do not perform a qualitative assessment, or if we determine that it is not more likely than not that the fair value of the reporting unit exceeds its carrying amount, then the goodwill impairment test becomes a quantitative analysis. If the fair value of a reporting unit is determined to be greater than the carrying value of the reporting unit, goodwill is deemed not to be impaired and no further testing is necessary. If the fair value of a reporting unit is less than the carrying value, a goodwill impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value limited to the total amount of the goodwill allocated to the reporting unit.

When determining the fair value of our reporting units, we use a DCF model based on our most current forecasts. We discount the related cash flow forecasts using the weighted average cost of capital method at the date of evaluation. Preparation of forecasts and selection of the discount rate for use in the DCF model involve significant judgments, and changes in these estimates could affect the estimated fair value of one or more of our reporting units and could result in a goodwill impairment charge in a future period. We also use market multiples which are obtained from quoted prices of comparable companies to corroborate our DCF model results. The combined estimated fair value of our reporting units from our DCF model often results in a premium over our market capitalization, commonly referred to as a control premium. We believe the implied control premium determined by our impairment analysis is reasonable based upon historic data of premiums paid on actual transactions within our industry.

We review intangible assets that are being amortized for impairment whenever events or changes in circumstance indicate that an asset group’s carrying value may not be recoverable. If we are required to record impairment charges in the future, they could materially impact our results of operations.

Contingencies

We define a contingency as an existing condition that involves a degree of uncertainty as to a possible gain or loss that will ultimately be resolved when one or more future events occur or fail to occur. Under U.S. GAAP, we are required to establish reserves for loss contingencies when the loss is probable and we can reasonably estimate its financial impact. We are required to assess the likelihood of material adverse judgments or outcomes, as well as potential ranges or probability of losses. We determine the amount of reserves required, if any, for contingencies after carefully analyzing each individual item. The required reserves may change due to new developments in each issue. We do not recognize gain contingencies until all contingencies are resolved.

Share-Based Payments

Share-based compensation expense is measured based on the grant date fair value and recognized over the requisite service period for awards that we ultimately expect to vest. For purposes of measuring share-based compensation expense, we consider whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. No adjustments were necessary for the years ended December 31, 2023, 2022, or 2021. We also estimate forfeitures at the time of grant based on our actual experience to date and revise our estimates, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

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Restricted Share Units

RSUs are service-based awards for which we recognize the associated compensation cost on a straight-line basis over the requisite service period. We estimate the fair value of the awards based on the market price of the underlying share on the date of grant, reduced by the present value of estimated dividends foregone during the vesting period where applicable.

Performance Share Awards

PSAs are performance-based awards for which vesting is dependent on the achievement of certain objectives. Such objectives may be made on a personal, group, or company level. We estimate the fair value of the awards based on the market price of the underlying share on the date of grant, reduced by the present value of estimated dividends foregone during the vesting period.

Compensation expense is recognized over the performance period. The number of shares issued on the vesting date will vary depending on the actual performance objectives achieved, which are based on a fixed number of potential outcomes. We make assessments of future performance using subjective estimates, such as long-term plans. As a result, changes in the underlying assumptions could have a material impact on the compensation expense recognized.

The largest plan is the LPP, which has a three-year performance period. As the percent of expected performance increases or decreases, the potential change in expense can go from 0% to 200% of the targeted total expense. The 2021 to 2023 performance period ended on December 31, 2023, the 2020 to 2022 performance period ended on December 31, 2022, and the 2019 to 2021 performance period ended on December 31, 2021. The LPP currently has two open performance periods: 2022 to 2024 and 2023 to 2025. A 10% upward adjustment in our estimated performance achievement percentage for both open performance periods would have increased our 2023 expense by approximately $8.7 million, while a 10% downward adjustment would have decreased our expense by approximately $8.7 million.

Income Taxes

We earn income in numerous countries and this income is subject to the laws of taxing jurisdictions within those countries.

The carrying values of deferred income tax assets and liabilities reflect the application of our income tax accounting policies and are based on management’s assumptions and estimates about future operating results and levels of taxable income, and judgments regarding the interpretation of the provisions of current accounting principles.

Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more likely than not that some portion of the deferred tax asset will not be realized. Considerations with respect to the realizability of deferred tax assets include the period of expiration of the deferred tax asset, historical earnings and projected future taxable income by jurisdiction as well as tax liabilities for the tax jurisdiction to which the tax asset relates. Significant management judgment is required in determining the assumptions and estimates related to the amount and timing of future taxable income. Valuation allowances are evaluated periodically and will be subject to change in each future reporting period as a result of changes in various factors.

We assess carryforwards and tax credits for realization as a reduction of future taxable income by using a “more likely than not” determination.

We base the carrying values of liabilities and assets for income taxes currently payable and receivable on management’s interpretation of applicable tax laws and incorporate management’s assumptions and judgments about using tax planning strategies in various taxing jurisdictions. Using different estimates, assumptions, and judgments in accounting for income taxes, especially those that deploy tax planning strategies, may result in materially different carrying values of income tax assets and liabilities and changes in our results of operations.

Accelerating Aon United Program

Restructuring charges related to the AAU Program are recognized within Accelerating Aon United Program expenses on the accompanying Consolidated Statements of Income and consists of the following cost activities:

Workforce reduction costs

Severance and related costs are generally determined based on amounts due under established severance plans. Typically, severance benefits are recognized when it is probable the benefit will be paid, and the amount is reasonably estimable. Most workforce reductions happen over a short span of time, so no discounting is necessary.

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Asset impairments for fixed assets

Asset impairments relate to fixed assets and are accounted for in the period when they become known by revising the useful life of fixed assets when there is a change in the estimated future benefits in or use of the asset, accordingly depreciation is accelerated to reflect the revised useful life.

Leases

For leased properties where we plan to permanently cease use of a space and have the intent and ability to sublease the property, we will test the ROU asset for impairment to determine if an impairment has occurred. The test for impairment will adjust the book value of the asset based on the net present value of the future cash flows expected from a sublease agreement using current market information for similar properties.

For properties where we plan to permanently cease use of a space and have no intent or ability to sublease the property, the amortization of the ROU asset will be accelerated and recognized on a straight-line basis from the decision date to the cease use date.

For the remaining lease term, we decrease the liability for payments and increase the liability for accretion of the discount. The discount reflects our incremental borrowing rate, which matches the lifetime of the liability. Significant changes in the discount rate selected or the estimations of sublease income could impact the amounts recorded in the Consolidated Statements of Income.

Other associated costs of exit and disposal activities

We recognize other costs associated with exit and disposal activities as they are incurred, including professional services fees, technology-related costs, and moving costs.

NEW ACCOUNTING PRONOUNCEMENTS

Note 2 “Summary of Significant Accounting Principles and Practices” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report contains a summary of our significant accounting policies, including a discussion of recently issued accounting pronouncements and their impact or future potential impact on our financial results, if determinable.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

We are exposed to potential fluctuations in earnings, cash flows, and the fair values of certain of our assets and liabilities due to changes in interest rates and foreign exchange rates. To manage the risk from these exposures, we enter into a variety of derivative instruments. We do not enter into derivatives or financial instruments for trading or speculative purposes.

The following discussion describes our specific exposures and the strategies we use to manage these risks. Refer to Note 2 “Summary of Significant Accounting Principles and Practices” of the Notes to Consolidated Financial Statements in Part II, Item 8 of this report for a discussion of our accounting policies for financial instruments and derivatives.

Foreign Exchange Risk

We are subject to foreign exchange rate risk. Our primary exposures include exchange rates between the U.S. dollar and the euro, the British pound, the Canadian dollar, the Australian dollar, the Indian rupee, and the Japanese yen. We use over-the-counter options and forward contracts to reduce the impact of foreign currency risk to our financial statements.

Additionally, some of our non-U.S. brokerage subsidiaries receive revenue in currencies that differ from their functional currencies. Our U.K. subsidiaries earn a portion of their revenue in U.S. dollars, euro, and Japanese yen, but most of their expenses are incurred in British pounds. At December 31, 2023, we have hedged approximately 45% of our U.K. subsidiaries’ expected exposures to the U.S. dollar, euro, and Japanese yen transactions for the years ending December 31, 2024 and 2025. We generally do not hedge exposures beyond three years.

We also use forward and option contracts to economically hedge foreign exchange risk associated with monetary balance sheet exposures, such as intercompany notes and current assets and liabilities that are denominated in a non-functional currency and are subject to remeasurement.

The potential loss in future earnings from foreign exchange derivative instruments resulting from a hypothetical 10% adverse change in year-end exchange rates would be $28 million and $18 million at December 31, 2024 and 2025, respectively.

The translated value of revenues and expenses from our international brokerage operations are subject to fluctuations in foreign exchange rates. If we were to translate prior year results at current year exchange rates, diluted earnings per share would have an unfavorable $0.17 impact during the year ended December 31, 2023. Further, adjusted diluted earnings per share, a

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non-GAAP measure as defined and reconciled under the caption “Review of Consolidated Results — Adjusted Diluted Earnings Per Share,” would have an unfavorable $0.17 impact during the year ended December 31, 2023 if we were to translate prior year results at current year exchange rates.

Interest Rate Risk

Our fiduciary investment income is affected by changes in international and domestic short-term interest rates. We monitor our net exposure to short-term interest rates and, as appropriate, hedge our exposure with various derivative financial instruments. This activity primarily relates to brokerage funds held on behalf of clients in the U.S. and in continental Europe. A hypothetical, instantaneous parallel decrease in the year-end yield curve of 100 BPS would cause a decrease, net of derivative positions, of $69 million to each of 2024 and 2025 pretax income. A corresponding increase in the year-end yield curve of 100 BPS would cause an increase, net of derivative positions, of $69 million to each of 2024 and 2025 pre-tax income.

We have long-term debt outstanding, excluding the current portion, with a fair market value of $9.2 billion and $8.7 billion as of December 31, 2023 and December 31, 2022, respectively. The fair value was greater than the carrying value by $0.8 billion at December 31, 2023, and $1.1 billion less than the carrying value at December 31, 2022. A hypothetical 1% increase or decrease in interest rates would change the fair value by a decrease of 7% or an increase of 8%, respectively, at December 31, 2023.

We have selected hypothetical changes in foreign currency exchange rates, interest rates, and equity market prices to illustrate the possible impact of these changes; we are not predicting market events.

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Item 8. Financial Statements and Supplementary Data

Report of Independent Registered Public Accounting Firm

To the Shareholders and the Board of Directors of Aon plc

Opinion on the Financial Statements

We have audited the accompanying consolidated statements of financial position of Aon plc (the Company) as of December 31, 2023 and 2022, the related consolidated statements of income, comprehensive income, shareholders’ equity (deficit) and cash flows for each of the three years in the period ended December 31, 2023, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023, in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February 16, 2024, expressed an unqualified opinion thereon.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the account or disclosure to which it relates.

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Realizability of Deferred Tax Assets

We have served as the Company’s auditor since 1986.

Chicago, Illinois

February 16, 2024

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Aon plc

Consolidated Statements of Income

Years Ended December 31

Revenue

Expenses

Amortization and impairment of intangible assets 89 113 147

Accelerating Aon United Program expenses 135 — —

Less: Net income attributable to noncontrolling interests 64 57 53

Net income attributable to Aon shareholders $ 2,564 $ 2,589 $ 1,255

Weighted average ordinary shares outstanding - basic 203.5 211.7 224.7

Weighted average ordinary shares outstanding - diluted 205.0 213.2 226.1

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Comprehensive Income

Years Ended December 31

Less: Net income attributable to noncontrolling interests 64 57 53

Net income attributable to Aon shareholders 2,564 2,589 1,255

Other comprehensive income (loss), net of tax:

Change in fair value of financial instruments 13 (13) 1

Foreign currency translation adjustments 276 (528) (289)

Postretirement benefit obligation (40) (211) 277

Total other comprehensive income (loss) 249 (752) (11)

Comprehensive income attributable to Aon shareholders $ 2,814 $ 1,837 $ 1,245

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Financial Position

As of December 31

(millions, except nominal value) 2023 2022

Assets

Current assets

Cash and cash equivalents $ 778 $ 690

Operating lease right-of-use assets 650 699

Other non-current assets 506 509

Liabilities and equity (deficit)

Liabilities

Current liabilities

Accounts payable and accrued liabilities $ 2,262 $ 2,114

Short-term debt and current portion of long-term debt 1,204 945

Non-current operating lease liabilities 641 693

Deferred tax liabilities 115 99

Pension, other postretirement, and postemployment liabilities 1,225 1,186

Other non-current liabilities 1,074 1,024

Equity (deficit)

Accumulated other comprehensive loss (4,373) (4,623)

Total Aon shareholders' deficit (826) (529)

Noncontrolling interests 84 100

Total liabilities and equity (deficit) $ 33,959 $ 32,704

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Shareholders’ Equity (Deficit)

Shares issued — employee stock compensation plans 1.7 (129) (1) — — (130)

Share-based compensation expense — 449 — — — 449

Dividends to shareholders ($1.99 per share) — — (447) — — (447)

Net change in fair value of financial instruments — — — 1 — 1

Net foreign currency translation adjustments — — — (288) (1) (289)

Net postretirement benefit obligation — — — 277 — 277

Net purchases of shares from noncontrolling interests — (8) — — (5) (13)

Shares issued — employee stock compensation plans 1.7 (156) (1) — — (157)

Share-based compensation expense — 397 — — — 397

Dividends to shareholders ($2.19 per share) — — (463) — — (463)

Net change in fair value of financial instruments — — — (13) — (13)

Net foreign currency translation adjustments — — — (528) — (528)

Net postretirement benefit obligation — — — (211) — (211)

Net purchases of shares from noncontrolling interests — (1) — — (1) (2)

Shares issued — employee stock compensation plans 1.6 (168) (1) — — (169)

Share-based compensation expense — 438 — — — 438

Dividends to shareholders ($2.41 per share) — — (490) — — (490)

Net change in fair value of financial instruments — — — 13 — 13

Net foreign currency translation adjustments — — — 277 (1) 276

Net postretirement benefit obligation — — — (40) — (40)

Net purchases of shares from noncontrolling interests — (190) — — (23) (213)

See accompanying Notes to Consolidated Financial Statements.

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Aon plc

Consolidated Statements of Cash Flows

Years Ended December 31

Cash flows from operating activities

Adjustments to reconcile net income to cash provided by operating activities:

Gain from sales of businesses (4) (54) (142)

Amortization and impairment of intangible assets 89 113 147

Change in assets and liabilities:

Accounts payable and accrued liabilities 13 (22) 264

Accelerating Aon United Program liabilities 99 — —

Pension, other postretirement and postemployment liabilities 8 (53) (124)

Other assets and liabilities 356 3 4

Cash flows from investing activities

Purchases for investments (67) (107) (91)

Net sales (purchases) of short-term investments - non fiduciary 85 (175) 15

Sale of businesses, net of cash and funds held on behalf of clients 5 81 218

Cash provided by (used for) investing activities (188) (449) 49

Cash flows from financing activities

Proceeds from issuance of shares 72 58 55

Cash paid for employee taxes on withholding shares (241) (215) (185)

Commercial paper issuances, net of repayments (27) (65) 671

Increase in fiduciary liabilities, net of fiduciary receivables 358 702 568

Cash dividends to shareholders (489) (463) (447)

Noncontrolling interests and other financing activities (232) (71) (125)

Reconciliation of cash and cash equivalents and funds held on behalf of clients:

Supplemental disclosures:

Income taxes paid, net of refunds $ 740 $ 546 $ 412

See accompanying Notes to Consolidated Financial Statements.

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Notes to Consolidated Financial Statements

1. Basis of Presentation

The accompanying Consolidated Financial Statements and Notes thereto have been prepared in accordance with U.S. GAAP. The Consolidated Financial Statements include the accounts of Aon plc and all of its controlled subsidiaries (“Aon” or the “Company”). Intercompany accounts and transactions have been eliminated. The Consolidated Financial Statements include, in the opinion of management, all adjustments (consisting of normal recurring adjustments and reclassifications) necessary to present fairly the Company’s consolidated financial position, results of operations, and cash flows for all periods presented.

Use of Estimates

The preparation of the accompanying Consolidated Financial Statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of reserves and expenses. These estimates and assumptions are based on management’s best estimates and judgments. Management evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the current economic environment. Management believes its estimates to be reasonable given the current facts available. Aon adjusts such estimates and assumptions when facts and circumstances dictate. Illiquid credit markets, volatile equity markets, and foreign currency exchange rate movements increase the uncertainty inherent in such estimates and assumptions. As future events and their effects cannot be determined with precision, actual results could differ significantly from these estimates. Changes in estimates resulting from continuing changes in the economic environment would, if applicable, be reflected in the Consolidated Financial Statements in future periods.

2. Summary of Significant Accounting Principles and Practices

Revenue Recognition

The Company generates revenues primarily through commissions, compensation from insurance and reinsurance companies for services provided to them, and fees from customers. Commissions and fees for brokerage services vary depending upon several factors, which may include the amount of premium, the type of insurance or reinsurance coverage provided, the particular services provided to a client, insurer, or reinsurer, and the capacity in which the Company acts. Compensation from insurance and reinsurance companies includes: (1) fees for consulting and analytics services and (2) fees and commissions for administrative and other services provided to or on behalf of insurers. In Aon’s capacity as an insurance and reinsurance broker, the service promised to the customer is placement of an effective insurance or reinsurance policy, respectively. The customer obtains control over the services promised by the Company at the completion of the insurance or reinsurance policy placement process once coverage is effective. Judgment is not typically required when assessing whether the coverage is effective. Fees from clients for advice and consulting services are dependent on the extent and value of the services provided. Payment terms for the Company’s principal service lines are discussed below; the Company believes these terms are consistent with current industry practices. Significant financing components are typically not present in Aon’s arrangements.

The Company recognizes revenue when control of the promised services is transferred to the customer in the amount that best reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements where control is transferred over time, an input or output method is applied that represents a faithful depiction of the progress towards completion of the performance obligation. For arrangements that include variable consideration, the Company assesses whether any amounts should be constrained. For arrangements that include multiple performance obligations, the Company allocates consideration based on their relative fair values.

Costs incurred by the Company in obtaining a contract are capitalized and amortized on a systematic basis that is consistent with the transfer of control of the services to which the asset relates, considering anticipated renewals when applicable. Certain contract related costs, including pre-placement brokerage costs, are capitalized as a cost to fulfill and are amortized on a systematic basis consistent with the transfer of control of the services to which the asset relates, which is generally less than one year.

The Company has elected to apply practical expedients to not disclose the revenue related to unsatisfied performance obligations if (1) the contract has an original duration of 1 year or less, (2) the Company has recognized revenue for the amount in which it has the right to bill, and (3) the variable consideration is allocated entirely to an unsatisfied performance obligation which is recognized as a seriesof distinct goods or services that form a single performance obligation.

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Disaggregation of Revenue

The following is a description of principal service lines from which the Company generates its revenue:

Commercial Risk Solutions includes retail brokerage, specialty solutions, global risk consulting and captives management, and Affinity programs. Revenue primarily includes insurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue is recorded net of allowances for estimated policy cancellations, which are determined based on an evaluation of historical and current cancellation data. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Commissions and fees for brokerage services may be invoiced near the effective date of the underlying policy or over the term of the arrangement in installments during the policy period.

Reinsurance Solutions includes treaty reinsurance, facultative reinsurance, Strategy and Technology Group, and capital markets. Revenue primarily includes reinsurance commissions and fees for services rendered. Revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement using output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services. For arrangements recognized over time, various output measures, including units delivered and time elapsed, are utilized to provide a faithful depiction of the progress towards completion of the performance obligation. Commissions and fees for brokerage services may be invoiced at the inception of the reinsurance period for certain reinsurance brokerage, or more commonly, over the term of the arrangement in installments based on deposit or minimum premiums for most treaty reinsurance arrangements.

Health Solutions includes consulting and brokerage, Human Capital, and Consumer Benefits Solutions. Revenue primarily includes insurance commissions and fees for services rendered. For brokerage commissions, revenue is predominantly recognized at a point in time upon the effective date of the underlying policy (or policies), or for a limited number of arrangements, over the term of the arrangement to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services using input or output measures, including units delivered or time elapsed, to provide a faithful depiction of the progress towards completion of the performance obligation. Revenue from health care exchange arrangements is typically recognized upon successful enrollment of participants. Commissions and fees for brokerage services may be invoiced at the effective date of the underlying policy or over the term of the arrangement in installments during the policy period. Payment terms for other services vary but are typically over the contract term in installments.

Wealth Solutions includes retirement consulting and pension administration, as well as investments. Revenue recognized for these arrangements is predominantly recognized over the term of the arrangement using input or output measures to depict the transfer of control of the services to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those services, or for certain arrangements, at a point in time upon completion of the services. For consulting arrangements recognized over time, revenue will be recognized based on a measure of progress that depicts the transfer of control of the services to the customer, utilizing an appropriate input or output measure to provide a reasonable assessment of the progress towards completion of the performance obligation including units delivered or time elapsed. Fees paid by customers for consulting services are typically charged on an hourly, project or fixed-fee basis, and revenue for these arrangements is typically recognized based on time incurred, days elapsed, or reports delivered. Revenue from time-and-materials or cost-plus arrangements are recognized as services are performed using input or output measures to provide a reasonable assessment of the progress towards completion of the performance obligation including hours worked, and revenue for these arrangements is typically recognized based on time and materials incurred. Revenue generated from the Company’s delegated investment business is generally earned as an agreed percentage based on AUM and, to a lesser extent, based on performance fees. Reimbursements received for out-of-pocket expenses are generally recorded as a component of revenue. Payment terms vary but are typically over the contract term in installments.

Share-based Compensation Expense

Share-based payments to employees, including grants of RSUs and PSAs, are measured based on grant date fair value. For purposes of measuring share-based compensation expense, the Company considered whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. No adjustments were necessary for the years ended December 31, 2023, 2022, or 2021. The Company recognizes compensation

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expense over the requisite service period for awards expected to ultimately vest. Forfeitures are estimated on the date of grant and revised if actual or expected forfeiture activity differs materially from original estimates.

Pension and Other Postretirement Benefits

The Company records net periodic cost relating to its pension and other postretirement benefit plans based on calculations that include various actuarial assumptions, including discount rates, assumed rates of return on plan assets, inflation rates, mortality rates, compensation increases, and turnover rates. The Company reviews its actuarial assumptions on an annual basis and modifies these assumptions based on current rates and trends. The effects of gains, losses, and prior service costs and credits are amortized over future service periods or future estimated lives if the plans are frozen as reflected in Other income (expense) within the Consolidated Statements of Income. The funded status of each plan, calculated as the fair value of plan assets less the benefit obligation, is reflected in the Company’s Consolidated Statements of Financial Position using a December 31 measurement date.

Earnings per Share

Basic earnings per share is computed by dividing net income available to ordinary shareholders by the weighted-average number of ordinary shares outstanding, including participating securities, which consist of unvested share awards with non-forfeitable rights to dividends. Diluted earnings per share is computed by dividing net income available to ordinary shareholders by the weighted average number of ordinary shares outstanding, which have been adjusted for the dilutive effect of potentially issuable ordinary shares, including certain contingently issuable shares. The diluted earnings per share calculation reflects the more dilutive effect of either (1) the two-class method that assumes that the participating securities have not been exercised, or (2) the treasury stock method.

Potentially issuable shares are not included in the computation of diluted earnings per share if their inclusion would be antidilutive.

Cash and Cash Equivalents and Short-term Investments

Cash and cash equivalents include cash balances and all highly liquid investments with initial maturities of three months or less. Short-term investments generally consist of money market funds. The estimated fair value of Cash and cash equivalents and Short-term investments approximates their carrying values.

At December 31, 2023, Cash and cash equivalents and Short-term investments totaled $1,147 million compared to $1,142 million at December 31, 2022, an increase of $5 million. Of the total balance, $120 million and $115 million was restricted as to its use at December 31, 2023 and 2022, respectively. Included within Short-term investments as of December 31, 2023 and 2022 balances, respectively, were £63.2 million ($80.4 million at December 31, 2023 exchanges rates) and £60.1 million ($72.5 million at December 31, 2022 exchange rates) of operating funds required to be held by the Company in the U.K. by the FCA, a U.K.-based regulator.

Fiduciary Assets and Liabilities

In its capacity as an insurance agent and broker, Aon collects premiums from insureds and, after deducting its commission, remits the premiums to the respective insurers. Aon also collects claims or refunds from insurers on behalf of insureds. Uncollected premiums from insureds and uncollected claims or refunds from insurers are recorded as Fiduciary assets in the Company’s Consolidated Statements of Financial Position. Unremitted insurance premiums and claims are held in a fiduciary capacity and the obligation to remit these funds is recorded as Fiduciary liabilities in the Consolidated Statements of Financial Position.

Funds held on behalf of clients represent fiduciary assets held by Aon for premiums collected from insureds but not yet remitted to insurance companies and claims collected from insurance companies but not yet remitted to insureds of $6.9 billion and $6.4 billion at December 31, 2023 and 2022, respectively. Fiduciary receivables were $9.4 billion and $9.5 billion at December 31, 2023 and 2022, respectively. These funds and a corresponding liability are included in Fiduciary assets and Fiduciary liabilities, respectively, in the accompanying Consolidated Statements of Financial Position.

Allowance for Doubtful Accounts

The Company’s estimate for allowance for credit losses with respect to receivables is based on a combination of factors, including evaluation of forward-looking information, historical write-offs, aging of balances, and other qualitative and quantitative analyses. Receivables, net included an allowance for doubtful accounts of $79 million and $76 million at December 31, 2023 and 2022, respectively.

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Fixed Assets

Fixed assets are stated at cost, less accumulated depreciation. Included in this category are certain capitalized costs incurred during the application development stage related to directly obtaining, developing, or enhancing internal use software. Depreciation and amortization are computed using the straight-line method over the estimated useful lives of the assets, which are generally as follows:

Asset Description Estimated Useful Life

Software Lesser of the life of an associated license, or 4 to 7 years

Furniture, fixtures and equipment 4 to 10 years

Computer equipment 4 to 6 years

Buildings 35 years

Automobiles 6 years

Goodwill and Intangible Assets

Goodwill represents the excess of purchase price over the fair value of the net assets acquired in the acquisition of a business. Goodwill is allocated to applicable reporting units. Upon disposition of a business entity, goodwill is allocated to the disposed entity based on the relative fair value of that entity compared to the fair value of the reporting unit in which it was included. Goodwill is not amortized, but instead is tested for impairment at least annually. The goodwill impairment test is performed at the reporting unit level. The Company may initially perform a qualitative analysis to determine if it is more likely than not that the goodwill balance is impaired. If a qualitative assessment is not performed or if a determination is made that it is not more likely than not that the value of the reporting unit exceeds its carrying amount, then the Company will perform a quantitative analysis. If the fair value of a reporting unit is determined to be greater than the carrying value of the reporting unit, goodwill is deemed not to be impaired and no further testing is necessary. If the fair value of a reporting unit is less than the carrying value, a goodwill impairment loss is recognized for the amount that the carrying amount of a reporting unit, including goodwill, exceeds its fair value limited to the total amount of the goodwill allocated to the reporting unit. Any resulting difference will be a charge to Amortization and impairment of intangible assets in the Consolidated Statements of Income in the period in which the determination is made. Fair value is determined using a combination of present value techniques and market prices of comparable businesses.

We classify our intangible assets acquired as either customer-related and contract based or technology and other intangible assets, which includes tradenames. Amortization basis and estimated useful lives by intangible asset type are generally as follows:

Intangible Asset Description Amortization Basis Estimated Useful Life

Technology and other intangibles Straight-line 5 to 7 years

Tradenames Straight-line 1 to 3 years

Derivatives

Derivative instruments are recognized in the Consolidated Statements of Financial Position at fair value. Where the Company has entered into master netting agreements with counterparties, the derivative positions are netted by counterparties and are reported accordingly in other assets or other liabilities. Changes in the fair value of derivative instruments are recognized in earnings each period, unless the derivative is designated and qualifies as a cash flow or net investment hedge.

The Company has historically designated the following hedging relationships for certain transactions: (1) a hedge of the change in fair value of a recognized asset or liability or firm commitment (“fair value hedge”), (2) a hedge of the variability in cash flows from a recognized variable-rate asset or liability or forecasted transaction (“cash flow hedge”), and (3) a hedge of the net investment in a foreign operation (“net investment hedge”).

In order for a derivative to qualify for hedge accounting, the derivative must be formally designated as a fair value, cash flow, or a net investment hedge by documenting the relationship between the derivative and the hedged item. The documentation must include a description of the hedging instrument, the hedged item, the risk being hedged, Aon’s risk management objective and strategy for undertaking the hedge, and the method for assessing the effectiveness of the hedge. Additionally, the hedge relationship must be expected to be highly effective at offsetting changes in either the fair value or cash flows of the hedged

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item at both the inception of the hedge and on an ongoing basis. Aon assesses the ongoing effectiveness of its hedges quarterly or more frequently if facts and circumstances require.

For a derivative designated as a fair value hedging instrument, the gain or loss is recognized in earnings in the period of change together with the offsetting loss or gain on the hedged item attributable to the risk being hedged. The effect is to reflect in earnings the extent to which the hedge is not effective in achieving offsetting changes in fair value. For a cash flow hedge that qualifies for hedge accounting, the change in fair value of a hedging instrument is recognized in Accumulated Other Comprehensive Income and subsequently reclassified to earnings in the same period the hedged item impacts earnings. For a net investment hedge, the change in fair value of the hedging instrument is recognized in Accumulated Other Comprehensive Income as part of the cumulative translation adjustment.

Changes in the fair value of a derivative that is not designated as part of a hedging relationship (commonly referred to as an “economic hedge”) are recorded in Other income (expense) in the Consolidated Statements of Income in the period of change.

The Company discontinues hedge accounting prospectively when (1) the derivative expires or is sold, terminated, or exercised, (2) the qualifying criteria are no longer met, or (3) management removes the designation of the hedging relationship.

Foreign Currency

Certain of the Company’s non-U.S. operations use their respective local currency as their functional currency. These operations that do not have the U.S. dollar as their functional currency translate their financial statements at the current rates of exchange in effect at the balance sheet date and revenues and expenses using rates that approximate those in effect during the period. The resulting translation adjustments are included in Net foreign currency translation adjustments within the Consolidated Statements of Shareholders’ Equity (Deficit). Further, gains and losses from the remeasurement of monetary assets and liabilities that are denominated in a non-functional currency of that entity are included in Other income (expense) within the Consolidated Statements of Income.

Income Taxes

Deferred income taxes are recognized for the effect of temporary differences between financial reporting and tax basis of assets and liabilities and are measured using the enacted marginal tax rates and laws that are currently in effect. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in the period when the rate change is enacted.

Deferred tax assets are reduced by valuation allowances if, based on the consideration of all available evidence, it is more likely than not that some portion of the deferred tax asset will not be realized. Deferred tax assets are realized by having sufficient future taxable income to allow the related tax benefits to reduce taxes otherwise payable. The sources of taxable income that may be available to realize the benefit of deferred tax assets are future reversals of existing taxable temporary differences, future taxable income exclusive of reversing temporary differences and carry-forwards, taxable income in carry-back years, and tax planning strategies that are both prudent and feasible.

The Company recognizes the effect of income tax positions only if sustaining those positions is more likely than not. Tax positions that meet the more likely than not recognition threshold but are not highly certain are initially and subsequently measured based on the largest amount of benefit that is greater than 50% likely of being realized upon settlement with the taxing authority. Only information that is available at the reporting date is considered in the Company’s recognition and measurement analysis, and events or changes in facts and circumstances are accounted for in the period in which the event or change in circumstance occurs.

The Company records penalties and interest related to unrecognized tax benefits in Income taxes in the Company’s Consolidated Statements of Income.

The Company releases income tax effects from Accumulated other comprehensive loss using the portfolio approach.

Leases

The Company leases office facilities, equipment, and automobiles under operating and finance leases. The Company’s lease obligations are primarily for the use of office facilities. The Company evaluates if a leasing arrangement exists upon inception of a contract. A contract contains a lease if the contract conveys the right to control the use of identified tangible assets for a period of time in exchange for consideration. Identified property, plant, or equipment may include a physically distinct portion of a larger asset, or a portion of an asset that represents substantially all of the capacity of the asset but is not physically distinct. The Company assesses whether a contract implicitly contains the right to control the use of a tangible asset that is not already owned. In addition, the Company subleases certain real estate properties to third parties, which are classified as operating leases.

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The Company’s leases expire at various dates and may contain renewal, expansion, or termination options. The exercise of lease renewal and expansion options are typically at the Company’s sole discretion and are only included in the determination of the lease term if the Company is reasonably certain to exercise the option. In addition, the Company’s lease agreements typically do not contain any material residual value guarantees or restrictive covenants.

ROU assets and lease liabilities are based on the present value of the minimum lease payments over the lease term. The Company has elected the practical expedient related to lease and non-lease components, as an accounting policy election for all asset classes, which allows a lessee to not separate non-lease components from lease components and instead account for consideration received in a contract as a single lease component. The Company’s lease agreements may include initial direct costs and lease incentives. Initial direct costs are incremental costs of a lease that would not have been incurred if the lease had not been obtained and are included in the measurement of the ROU asset. Payments made to or on behalf of the Company, such as tenant improvement allowances, represent incentives that are considered reductions to the ROU asset and lease expense over the lease term.

The Company made a policy election to not recognize ROU assets and lease liabilities that arise from leases with an initial term of twelve months or less in the Consolidated Statements of Financial Position. However, the Company recognized these lease payments in the Consolidated Statements of Income on a straight-line basis over the lease term and variable lease payments in the period in which the expense was incurred. The Company applies this accounting policy across all classes of underlying assets.

A portion of the Company’s lease agreements include variable lease payments that are not recorded in the initial measurement of the lease liability and ROU asset balances. For real estate arrangements, base rental payments may be escalated according to annual changes in the CPI or other indices. The escalated rental payments based on the estimated CPI at the lease commencement date are included within minimum rental payments; however, changes in CPI are considered variable in nature and are recognized as variable lease costs in the period in which the obligation is incurred. Additionally, real estate lease agreements may include other variable payments related to operating expenses charged by the landlord based on actual expenditures. Information technology equipment agreements may include variable payments based on usage of the equipment. These expenses are also recognized as variable lease costs in the period in which the expense is incurred.

Where Aon has provided notice of cancellation pursuant to a lease agreement, the lease is modified with the associated ROU asset and the related lease liability remeasured, which may include any additional termination penalties incurred that were not previously included within the lease liability. To the extent that the associated ROU assets and lease liabilities are removed, a corresponding gain or loss is recorded.

The Company utilizes discount rates to determine the present value of the lease payments based on information available at the commencement date of the lease. As the rate implicit in each lease is not typically readily available, the Company uses an incremental borrowing rate based on factors such as the lease term and the economic environment where the lease exists to determine the appropriate present value of future lease payments. When determining the incremental borrowing rate, the Company considers the rate of interest it would pay on a secured borrowing in an amount equal to the lease payments for the underlying asset under similar terms.

Operating leases are included in Operating lease ROU assets, Other current liabilities, and Non-current operating lease liabilities in the Consolidated Statements of Financial Position. Finance leases are included in Other non-current assets, Other current liabilities, and Other non-current liabilities in the Consolidated Statements of Financial Position.

Principles of Consolidation

The accompanying Consolidated Financial Statements include the accounts of Aon plc and those entities in which the Company has a controlling financial interest. To determine if Aon holds a controlling financial interest in an entity, the Company first evaluates if it is required to apply the variable interest model to the entity, otherwise, the entity is evaluated under the voting interest model. When Aon holds rights that give it the power to direct the activities of a VIE that most significantly impact the VIE’s economic performance, combined with a variable interest that gives the right to receive potentially significant benefits or the obligation to absorb potentially significant losses, the Company has a controlling financial interest in that VIE. If the Company is the primary beneficiary of a VIE, the Company consolidates the entity and reflects any relevant non-controlling interest of other beneficiaries of that entity on the Statement of Consolidated Financial Position. Aon’s interest in VIEs as of December 31, 2023 was insignificant.

Aon holds a controlling financial interest in entities that are not VIEs when it, directly or indirectly holds more than 50% of the voting rights and the noncontrolling interest holders do not hold substantive participating rights.

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New Accounting Pronouncements

Accounting Standards Issued But Not Yet Adopted

Improvements to Reportable Segment Disclosures

In November 2023, the FASB issued new accounting guidance, requiring new segment disclosures under ASC 280, Segment Reporting, including disclosure of significant segment expense categories and amounts that are regularly reported to the CODM and included in the segment’s profit or loss. Additionally, all disclosure requirements under ASC 280 including new requirements under this new guidance, will be required on an interim basis. The new guidance is effective for Aon for the year ended December 31, 2024 and interim periods thereafter, with early adoption permitted. An entity will apply the new guidance on a retrospective basis for all periods presented. The Company is currently evaluating the impact the guidance will have on the Notes to Consolidated Financial Statements.

Improvements to Income Tax Disclosures

In December 2023, the FASB issued new accounting guidance under ASC 740, Income Taxes, which requires additional income tax disclosures on an annual basis, including disaggregation of information presented within the reconciliation of the expected tax to the reported tax by specific categories, with certain reconciling items 5% or greater broken out by nature and/or jurisdiction. The new guidance also requires disclosure of income taxes paid, net of refunds, broken out by federal, state/local and foreign, including disclosure of individual jurisdictions when greater than 5% of total net income taxes paid. The new guidance is effective for Aon for the year ended December 31, 2025, with early adoption permitted. The Company is evaluating the period of adoption and transition approach, as well as the impact the disclosures will have on the Notes to Consolidated Financial Statements.

3. Revenue from Contracts with Customers

Disaggregation of Revenue

The following table summarizes revenue from contracts with customers by principal service line (in millions):

Years Ended December 31

Consolidated revenue from contracts with customers by geographic area, which is attributed on the basis of where the services are performed, is as follows (in millions):

Years Ended December 31

Europe, Middle East, & Africa other than U.K. and Ireland 2,672 2,443 2,565

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Contract Costs

Changes in the net carrying amount of costs to fulfill contracts with customers are as follows (in millions):