ARCH CAPITAL GROUP LTD.

Throughout this filing, we present our operations in the way we believe will be the most meaningful and useful to investors, analysts, rating agencies and others who use our financial information in evaluating the performance of our company. This presentation includes the use of after-tax operating income available to Arch common shareholders, which is defined as net income available to Arch common shareholders, excluding net realized gains or losses (which includes, but is not limited to, realized and unrealized changes in the fair value of equity securities and assets accounted for using the fair value option, realized and unrealized gains or losses on derivative instruments, changes in the allowance for credit losses on financial assets and gains or losses realized from the acquisition or disposition of subsidiaries), equity in net income or loss of investments accounted for using the equity method, net foreign exchange gains or losses, transaction costs and other, net of income taxes, and the use of annualized operating return on average common equity. The presentation of after-tax operating income available to Arch common shareholders and annualized operating return on average common equity are non-GAAP financial measures as defined in Regulation G. The reconciliation of such measures to net income available to Arch common shareholders and annualized net income return on average common equity (the most directly comparable GAAP financial measures) in accordance with Regulation G is included under “Results of Operations” below.

We believe that net realized gains or losses, equity in net income or loss of investments accounted for using the equity method, net foreign exchange gains or losses and transaction costs and other in any particular period are not indicative of the performance of, or trends in, our business. Although net realized gains or losses, equity in net income or loss of investments accounted for using the equity method and net foreign exchange gains or losses are an integral part of our operations, the decision to realize these items are independent of the insurance underwriting process and result, in large part, from general economic and financial market conditions. Furthermore, certain users of our financial information believe that, for many companies, the timing of the realization of investment gains or losses is largely opportunistic. In addition, changes in the allowance for credit losses and net impairment losses recognized in earnings on our investments represent other-than-temporary declines in expected recovery values on securities without actual realization. Furthermore, we exclude net realized gains or losses from the acquisition or disposition of subsidiaries, due to their non-recurring nature, such items are not indicative of the performance of, or trends in, our business performance.

The use of the equity method on certain of our investments funds that invest in fixed maturity securities is driven by the ownership structure of such funds (either limited partnerships or limited liability companies). In applying the equity method, these investments are initially recorded at cost and are subsequently adjusted based on our proportionate share of the net income or loss of the funds (which include changes in the market value of the underlying securities in the funds). This method of accounting is different from the way in which we account for our other investments; and the timing of the recognition of equity in net income or loss of investments accounted for using the equity method may differ from gains or losses in the future upon sale or maturity of such investments.

Transaction costs and other include integration, advisory, financing, legal, severance, incentive compensation and all other transaction costs directly related to acquisitions. We believe that transaction costs and other, due to their nonrecurring nature, are not indicative of the performance of, or trends in, our business performance.

We believe that showing net income available to Arch common shareholders exclusive of the items referred to above reflects the underlying fundamentals of our business since we evaluate the performance of and manage our business to produce an underwriting profit. In addition to presenting net income available to Arch common shareholders, we believe that this presentation enables investors and other users of our financial information to analyze our performance in a manner similar to how management analyzes performance. We also believe that

this measure follows industry practice and, therefore, allows the users of financial information to compare our performance with our industry peer group. We believe that the equity analysts and certain rating agencies that follow us and the insurance industry as a whole generally exclude these items from their analyses for the same reasons.

Our segment information includes the presentation of consolidated underwriting income or loss. Such measures represent the pre-tax profitability of our underwriting operations and include net premiums earned plus other underwriting income, less losses and loss adjustment expenses, acquisition expenses and other operating expenses. Other operating expenses include those operating expenses that are incremental and/or directly attributable to our individual underwriting operations. Underwriting income or loss does not incorporate certain income and expense items which are included in corporate. While these measures are presented innote 4, “Segment Information,” to our consolidated financial statements in Item 8, they are considered non-GAAP financial measures when presented elsewhere on a consolidated basis. The reconciliations of underwriting income or loss to income before income taxes (the most directly comparable GAAP financial measure) on a consolidated basis, in accordance with Regulation G, is shown innote 4, “Segment Information,” to our consolidated financial statements in Item 8.

We measure segment performance for our three underwriting segments based on underwriting income or loss. We do not manage our assets by underwriting segment, with the exception of goodwill and intangible assets, and, accordingly, investment income, income from operating affiliates and other non-underwriting related items are not allocated to each underwriting segment.

Our presentation of segment information includes the use of a current year loss ratio which excludes favorable or adverse development in prior year loss reserves. This ratio is a non-GAAP financial measure as defined in Regulation G. The reconciliation of such measure to the loss ratio (the most directly comparable GAAP financial measure) in accordance with Regulation G is shown on the individual segment pages. Management utilizes the current year loss ratio in its analysis of the underwriting performance of each of our underwriting segments. Effective in the 2025 period, the ‘Other operating expense ratio’ includes ‘Other underwriting income.’

Total return on investments includes investment income, equity in net income or loss of investments accounted for using the equity method, net realized gains or losses (excluding changes in the allowance for credit losses on non-investment related financial assets) and the change in unrealized gains or losses generated by Arch’s investment portfolio. Total return is calculated on a pre-tax basis and before investment expenses, and reflects the effect of financial market conditions along with foreign currency fluctuations. In addition, total return incorporates the timing of investment returns during the periods. There is no directly comparable GAAP financial measure for total return. Management uses total return on investments as a key measure of the return generated to Arch common shareholders on the capital held in the business, and compares the return generated by our investment portfolio against benchmark returns which we measured our portfolio against during the periods.

RESULTS OF OPERATIONS

The following table summarizes our consolidated financial data, including a reconciliation of net income available to Arch common shareholders to after-tax operating income available to Arch common shareholders. See“Comment on Non-GAAP Financial Measures.”

(1) Net realized gains or losses include, but is not limited to, realized and unrealized changes in the fair value of equity securities and assets accounted for using the fair value option, realized and unrealized gains and losses on derivative instruments, changes in the allowance for credit losses on financial assets and gains or losses realized from the acquisition or disposition of subsidiaries.

(2) Income tax on net realized gains or losses, equity in net income or loss of investments accounted for using the equity method, net foreign exchange gains or losses and transaction costs and other reflects the relative mix reported by jurisdiction and the varying tax rates in each jurisdiction.

Segment Information

We classify our businesses into three underwriting segments: insurance, reinsurance and mortgage. Our insurance, reinsurance and mortgage segments each have managers who are responsible for the overall profitability of their respective segments and who are directly accountable to our chief operating decision-makers, the Chief Executive Officer of Arch Capital and the Chief Financial Officer and Treasurer of Arch Capital. The chief operating decision- makers do not assess performance, measure return on equity or make resource allocation decisions on a line of business basis. Management measures segment performance for our three underwriting segments based on underwriting income or loss. We do not manage our assets by underwriting segment, with the exception of goodwill and intangible assets and accordingly investment income is not allocated to each underwriting segment.

We determined our reportable segments using the management approach described in accounting guidance regarding disclosures about segments of an enterprise and related information. The accounting policies of the segments are the same as those used for the preparation of our consolidated financial statements. Inter-segment business is allocated to the segment accountable for the underwriting results.

Insurance Segment

The following tables set forth our insurance segment’s underwriting results:

The insurance segment consists of our insurance underwriting units which offer specialty product lines on a worldwide basis, as described innote 4, “Segment Information,” to our consolidated financial statements in Item 8.

The following tables set forth our insurance segment’s net premiums written by major line of business:

Net premiums written by the insurance segment were 13.4% higher in 2025 than in 2024. Growth in net premiums written primarily reflected the impact of the MCE Acquisition.

The following tables set forth our insurance segment’s net premiums earned by major line of business:

Net premiums written are primarily earned on a pro rata basis over the terms of the policies for all products, usually 12 months. Net premiums earned by the insurance segment were 17.3% higher in 2025 than in 2024, reflecting changes in net premiums written over the previous five quarters.

Other Underwriting Income (Loss).

Other underwriting income, which includes revenue earned from underwriting-related activities covered under existing service contracts, was $36 million in 2025, compared to nil in 2024.

The table below shows the components of the insurance segment’s loss ratio:

The insurance segment’s current year loss ratio in 2025 was consistent with 2024. The 2025 loss ratio included 4.4 points of current year catastrophic event activity, compared to 4.6 points in 2024. The current year loss ratio for the 2025 period also reflected the impact of the MCE Acquisition and changes in mix of business.

The insurance segment’s net favorable development was $43 million, or 0.6 points, for 2025, compared to $37 million, or 0.5 points, for 2024. Seenote 5, “Reserve for Losses and Loss Adjustment Expenses,” to our consolidated financial statements in Item 8 for information about the insurance segment’s prior year reserve development.

The insurance segment’s underwriting expense ratio was 33.9% in 2025, compared to 33.4% in 2024.

Reinsurance Segment

The following tables set forth our reinsurance segment’s underwriting results:

The reinsurance segment consists of our reinsurance underwriting units which offer specialty product lines on a worldwide basis, as described innote 4, “Segment Information,” to our consolidated financial statements in Item 8.

The following tables set forth our reinsurance segment’s net premiums written by major line of business:

Net premiums written by the reinsurance segment were 1.7% lower in 2025 than in 2024. The lower level of net premiums written primarily reflected non-renewals and share decreases in the specialty line of business offset, in part, by increases in casualty.

The following tables set forth our reinsurance segment’s net premiums earned by major line of business:

Net premiums earned in 2025 were 12.2% higher than in 2024, reflecting changes in net premiums written over the previous five quarters, including the mix and type of business written.

Other Underwriting Income (Loss).

Other underwriting income, which includes revenue earned from underwriting-related activities covered under existing service contracts was $159 million in 2025, compared to $9 million in 2024.

The table below shows the components of the reinsurance segment’s loss ratio:

The reinsurance segment’s current year loss ratio was 1.5 points lower in 2025 than in 2024. The 2025 loss ratio included 8.5 points for current year catastrophic event activity, primarily related to the California wildfires, compared to 11.8 points in 2024, primarily related to Hurricanes Milton, Helene and a series of other global events. The current year loss ratio for 2025 also reflected changes in mix of business.

The reinsurance segment’s net favorable development was $322 million, or 4.0 points, for 2025, compared to $188 million, or 2.6 points, for 2024, Seenote 5, “Reserve for Losses and Loss Adjustment Expenses,” to our consolidated financial statements in Item 8 for information about the reinsurance segment’s prior year reserve development.

The underwriting expense ratio for the reinsurance segment was 24.0% in 2025, compared to 23.5% in 2024. The increase in the 2025 period primarily reflected lower profit and sliding scale commissions on ceded business.

Mortgage Segment

The following tables set forth our mortgage segment’s underwriting results.

The following table sets forth our mortgage segment’s net premiums written by underwriting unit:

Net premiums written for 2025 were 4.7% lower than in 2024. The reduction in net premiums written in the 2025 period primarily reflected lower gross premiums written and expenses related to tender offers of certain Bellemeade Re mortgage insurance linked notes.

The persistency rate of the U.S. primary portfolio of mortgage loans was 81.8% at December 31, 2025 compared to 82.1% at December 31, 2024. The persistency rate represents the percentage of mortgage insurance in force at the beginning of a 12 month period that remains in force at the end of such period.

The following tables provide details on the new insurance written (“NIW”) generated by U.S. primary mortgage insurance operations. NIW represents the original principal balance of all loans that received coverage during the period.

(1)Represents the original principal balance of all loans that received coverage during the period.

The following table sets forth our mortgage segment’s net premiums earned by underwriting unit:

Net premiums earned for 2025 were 4.8% lower than in 2024, reflecting changes in net premiums written over the previous five quarters.

Other Underwriting Income.

Other underwriting income, which is primarily related to GSE risk-sharing transactions services, was $22 million for 2025, compared to $17 million for 2024.

The table below shows the components of the mortgage segment’s loss ratio:

Unlike property and casualty business for which we estimate ultimate losses on premiums earned, losses on U.S. primary mortgage insurance business are only recorded at the time a borrower is delinquent on their mortgage, in accordance with primary mortgage insurance industry practice. Because our primary mortgage insurance reserving process does not take into account the impact of future losses from loans that are not delinquent, mortgage insurance loss reserves are not an estimate of ultimate losses. In addition to establishing loss reserves for delinquent loans, under GAAP, we are required to establish a premium deficiency reserve for our mortgage insurance products if the amount of expected future losses and maintenance costs exceeds expected future premiums, existing reserves and the anticipated investment income for such product. We assess the need for a premium deficiency reserve on a quarterly basis and perform a full analysis annually. No such reserve was established during 2025 or 2024.

The mortgage segment’s current year loss ratio was 1.2 points higher in 2025 compared to 2024. The higher current year loss ratio in 2025 period reflected slightly higher new delinquencies and the impact of the Bellemeade Re tender offers noted above. The percentage of loans in default on U.S. primary mortgage insurance increased from 2.09% at December 31, 2024 to 2.17% at December 31, 2025.

We insure mortgages for homes in areas that have been impacted by catastrophic events. Generally, mortgage insurance losses occur only when a credit event occurs and, following a physical damage event, when the home is restored to pre-storm condition. Our ultimate claims exposure will depend on the number of delinquency notices received and the ultimate claim rate related to such notices. In the event of natural disasters, cure rates are influenced by the adequacy of homeowners and flood insurance carried on a related property, and a borrower's access to aid from government entities and private organizations, in addition to other factors which generally impact cure rates in unaffected areas.

The mortgage segment’s net favorable development was $235 million, or 20.2 points, for 2025, compared to $282 million, or 23.0 points, for 2024. Seenote 5, “Reserve for Losses and Loss Adjustment Expenses,” to our consolidated financial statements in Item 8 for information about the mortgage segment’s prior year reserve development.

The underwriting expense ratio for the mortgage segment was 15.0% for 2025, compared to 17.0% for 2024. The decrease in the 2025 period primarily reflects a lower headcount as a result of the 2024 voluntary separation program.

Corporate

The Company’s corporate results include net investment income, net realized gains or losses (which includes, but is not limited to, realized and unrealized changes in the fair value of equity securities and assets accounted for using the fair value option, realized and unrealized gains or losses on derivative instruments, changes in the allowance for credit losses on financial assets and gains or losses realized from the acquisition or disposition of subsidiaries), equity in net income or loss of investments accounted for using the equity method, other income or loss, corporate expenses, transaction costs and other, amortization of intangible assets, interest expense, net foreign exchange gains or losses, income taxes, income from operating affiliates and items related to our non-cumulative preferred shares.

Net Investment Income.

The components of net investment income were derived from the following sources:

(1) Amounts include dividends and other distributions on investment funds, term loan investments, funds held balances, cash balances and other items.

(2) Investment expenses were approximately 0.23% of average invested assets for 2025, compared to 0.26% for 2024.

The pre-tax investment income yield was 4.11% for 2025, compared to 4.25% for 2024. The pre-tax investment income yields were calculated based on amortized cost. Net cash flow from operating activities contributed $6.2 billion in 2025, which increased our invested asset base and contributed to the growth in net investment income. Yields on future investment income may vary based on financial market conditions, investment allocation decisions and other factors.

Net Realized Gains or Losses.

We recorded net realized gains of $464 million for 2025, compared to net realized gains of $197 million for 2024. Amounts in both periods reflected sales of investments as well as the impact of financial market movements on the Company’s equity securities and investments accounted for under the fair value option method. Amounts in the 2025 period also include losses related to the impairment and sale of certain alternative investments accounted for under the equity method. Currently, our portfolio is actively managed to maximize total return within certain guidelines. The effect of financial market movements on the investment portfolio will directly impact net realized gains or losses as the portfolio is rebalanced. Net realized gains or losses from the sale of fixed maturities primarily results from our decisions to reduce credit exposure, to change duration targets, to rebalance our portfolios or due to relative value determinations.

Net realized gains or losses also include realized and unrealized contract gains and losses on our derivative instruments, changes in the fair value of assets accounted for using the fair value option and in the fair value of equities, along with changes in the allowance for credit losses on financial assets, net impairment losses recognized in earnings and gains or losses realized from the acquisition or disposition of subsidiaries. Seenote 9, “Investment Information—Net Realized Gains (Losses),” andnote 9, “Investment Information—Allowance for Expected Credit Losses,” to our consolidated financial statements for additional information.

Equity in Net Income (Loss) of Investments Accounted for Using the Equity Method.

We recorded $504 million of equity in net income related to investments accounted for using the equity method for 2025, compared to $580 million for 2024. Investments accounted for using the equity method totaled $6.5 billion at December 31, 2025, compared to $6.0 billion at December 31, 2024. Seenote 9, “Investment Information—Equity in Net Income (Loss) of Investments Accounted For Using the Equity Method,” to our consolidated financial statements in Item 8 for additional information.

Other Income or Losses

Other income for 2025 was $54 million, compared to $42 million for 2024. Amounts in both periods primarily reflect changes in the cash surrender value of our investment in corporate-owned life insurance.

Corporate Expenses.

Corporate expenses were $57 million for 2025, compared to $119 million for 2024. Such expenses primarily represent certain holding company costs necessary to support our worldwide operations and costs associated with operating as a publicly traded company. The 2025 period reflected Bermuda substance-based tax credits enacted in December 2025 with retroactive effect to January 1, 2025.

Transaction Costs and Other.

Transaction costs and other were $75 million for 2025, compared to $81 million for 2024. The amounts for both the 2025 and 2024 periods primarily reflect direct costs related to the MCE Acquisition and ongoing integration efforts.

Amortization of Intangible Assets.

Amortization of intangible assets for 2025 was $193 million, compared to $235 million for 2024. Amounts in both 2025 and 2024 primarily related to amortization of finite-lived intangible assets acquired as part of the MCE Acquisition.

Interest Expense.

Interest expense was $148 million for 2025, compared to $141 million for 2024. Interest expense primarily reflects amounts related to our outstanding senior notes.

Net Foreign Exchange Gains or Losses.

Net foreign exchange losses for 2025 were $128 million, compared to net foreign exchange gains for 2024 of $75 million. Amounts in such periods were primarily unrealized and resulted from the effects of revaluing our net insurance liabilities required to be settled in foreign currencies at each balance sheet date.

Income Tax Expense.

Our income tax provision on income before income taxes resulted in an expense of 14.7% for 2025, compared to an expense of 7.7% for 2024. Our effective tax rate fluctuates from year to year consistent with the relative mix of income or loss reported by jurisdiction and the varying tax rates in each jurisdiction. The increase in the 2025 period is primarily attributed to the enactment of the Corporate Income Tax Act 2023 by the Government of Bermuda, which established a 15% corporate income tax effective January 1, 2025. See

note 15, “Income Taxes,” to our consolidated financial statements in Item 8.

Income (Loss) from Operating Affiliates.

We recorded $180 million of net income from our operating affiliates in 2025, compared to $200 million in 2024. Amounts in both periods primarily reflected amounts related to our investments in Somers Group Holdings Ltd. and Coface SA. Seenote 9, “Investment Information—Investments in Operating Affiliates,” to our consolidated financial statements for additional information.

SUMMARY OF CRITICAL ACCOUNTING ESTIMATES

The preparation of consolidated financial statements in accordance with GAAP requires us to make many estimates and judgments that affect the reported amounts of assets, liabilities (including reserves), revenues and expenses, and related disclosures of contingent liabilities. On an ongoing basis, we evaluate our estimates, including those related to revenue recognition, insurance and other reserves, reinsurance recoverables, allowance for current expected credit losses, investment valuations, goodwill and intangible assets, bad debts, income taxes, contingencies and litigation. We base our estimates on historical experience, where possible, and on various other assumptions that we believe to be reasonable under the circumstances, which form the basis for our judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results will differ from these estimates and such differences may be material. We believe that the following critical accounting policies affect significant estimates used in the preparation of our consolidated financial statements.

Loss Reserves

We are required by applicable insurance laws and regulations and GAAP to establish reserves for losses and loss adjustment expenses, or “Loss Reserves”, that arise from the business we underwrite. Loss Reserves for our insurance, reinsurance and mortgage operations are balance sheet liabilities representing estimates of future amounts required to pay losses and loss adjustment expenses for insured or reinsured events which have occurred at or before the balance sheet date. Loss Reserves do not reflect contingency reserve allowances to account for future loss occurrences. Losses arising from future events will be estimated and recognized at the time the losses are incurred and could be substantial. Seenote 6, “Short Duration Contracts,” to our consolidated financial statements in Item 8 for additional information on our reserving process.

At December 31, 2025 and 2024, our Loss Reserves, net of unpaid losses and loss adjustment expenses recoverable, by type and by operating segment were as follows:

At December 31, 2025 and 2024, the insurance segment’s Loss Reserves by major line of business, net of unpaid losses and loss adjustment expenses recoverable, were as follows:

At December 31, 2025 and 2024, the reinsurance segment’s Loss Reserves by major line of business, net of unpaid losses and loss adjustment expenses recoverable, were as follows:

At December 31, 2025 and 2024, the mortgage segment’s Loss Reserves by major line of business, net of unpaid losses and loss adjustment expenses recoverable, were as follows:

Potential Variability in Loss Reserves

The following tables summarize the effect of reasonably likely scenarios on the key actuarial assumptions used to estimate our Loss Reserves, net of unpaid losses and loss adjustment expenses recoverable, at December 31, 2025 by underwriting segment and reserving lines. Seenote 6, “Short Duration Contracts,” to our consolidated financial statements in Item 8 for a description of the lines of business included in each reserving line.

The scenarios shown in the tables summarize the effect of (i) changes to the expected loss ratio selections used at December 31, 2025, which represent loss ratio point increases or decreases to the expected loss ratios used, and (ii) changes to the loss development patterns used in our reserving process at December 31, 2025, which represent claims reporting that is either slower or faster than the reporting patterns used. We believe that the illustrated sensitivities are indicative of the potential variability inherent in the estimation process of those parameters. The results show the impact of varying each key actuarial assumption using the chosen sensitivity on our Loss Reserves, on a net basis and across all accident years.

It is not necessarily appropriate to sum the total impact for a specific factor or the total impact for a specific business category as the business categories are not perfectly correlated. In addition, the potential variability shown in the tables above are reasonably likely scenarios of changes in our key assumptions at December 31, 2025 and are not meant to be a “best case” or “worst case” series of outcomes and therefore, it is possible that future variations may be more or less than the amounts set forth above.

For our mortgage segment, we considered the sensitivity of loss reserve estimates at December 31, 2025 by assessing the potential changes resulting from a parallel shift in severity and default to claim rate. For example, assuming all other factors remain constant, for every one percentage point change in primary claim severity (which we estimate to be approximately 30% of the unpaid principal balance at December 31, 2025), we estimated that our loss reserves would change by approximately $15 million at December 31, 2025. For every one percentage point change in our primary net default to claim rate (which we estimate to be approximately 22% at December 31, 2025), we estimated a $20 million change in our loss reserves at December 31, 2025.

Simulation Results

In order to illustrate the potential volatility in our Loss Reserves, we used a Monte Carlo simulation approach to simulate a range of results based on various probabilities. Both the probabilities and related modeling are subject to inherent uncertainties. The simulation relies on a significant number of assumptions, such as the potential for multiple entities to react similarly to external events, and includes other statistical assumptions. The simulation results shown for each segment do not add to the total simulation results, as the individual segment simulation results do not reflect the diversification effects across our segments.

At December 31, 2025, our recorded Loss Reserves by underwriting segment, net of unpaid losses and loss adjustment expenses recoverable, and the results of the simulation were as follows:

(1) Net of reinsurance recoverables.

(2) Simulation results indicate that a 90% probability exists that the net reserves for losses and loss adjustment expenses will not exceed the indicated amount.

(3) Simulation results indicate that a 10% probability exists that the net reserves for losses and loss adjustment expenses will be at or below the indicated amount.

For informational purposes, based on the total simulation results, a change in our Loss Reserves to the amount indicated at the 90th percentile would result in a decrease in income before income taxes of approximately $4.5 billion, or $11.98 per diluted share, while a change in our Loss Reserves to the amount indicated at the 10th percentile would result in an increase in income before income taxes of approximately $4.3 billion, or $11.32 per diluted share. The simulation results noted above are informational only, and no assurance can be given that our ultimate losses will not be significantly different than the simulation results shown above, and such differences could directly and significantly impact earnings favorably or unfavorably in the period they are determined. We do not have significant exposure to pre-2002 liabilities, such as asbestos-related illnesses and other long-tail liabilities. It is difficult to provide meaningful trend information for certain liability/casualty coverages for which the claim-tail may be especially long, as claims are often reported and ultimately paid or settled years, or even decades, after the related loss events occur. Any estimates

and assumptions made as part of the reserving process could prove to be inaccurate due to several factors, including the fact that for certain lines of business relatively limited historical information has been reported to us through December 31, 2025. Accordingly, the reserving for incurred losses in these lines of business could be subject to greater variability. See Item 1A, “Risk Factors – Risks Relating to Our Industry, Business & Operations – Underwriting risks and reserving for losses are based on probabilities and related modeling, which are subject to inherent uncertainties.”

Mortgage Operations Supplemental Information

The mortgage segment’s insurance in force (“IIF”) and risk in force (“RIF”) were as follows at December 31, 2025 and 2024:

(1) Represents the aggregate dollar amount of each insured mortgage loan’s current principal balance. Such amounts are shown before external reinsurance.

(2) The aggregate dollar amount of each insured mortgage loan’s current principal balance multiplied by the insurance coverage percentage specified in the policy for insurance policies issued and after contract limits and/or loss ratio caps for risk-sharing or reinsurance transactions. Such amounts are shown before external reinsurance.

The insurance in force and risk in force for our U.S. primary mortgage insurance business by policy year were as follows at December 31, 2025:

(1)Represents the ending percentage of loans in default.

The insurance in force and risk in force for our U.S. primary mortgage insurance business by policy year were as follows at December 31, 2024:

(1)Represents the ending percentage of loans in default.

The following tables provide supplemental disclosures on risk in force for our U.S. primary mortgage insurance business at December 31, 2025 and 2024:

The following table provides supplemental disclosures for our U.S. primary mortgage insurance business related to insured loans and loss metrics for the years ended December 31, 2025 and 2024:

(1) Represents delinquent loans related to the acquisition of RMIC Companies, Inc.

(2) Includes first lien primary and pool policies.

(3) Represents total direct first lien paid claims divided by RIF of loans for which claims were paid, excluding paid claim settlements.

The risk-to-capital ratio, which represents total current (non-delinquent) risk in force, net of reinsurance, divided by total statutory capital, for Arch MI U.S. was approximately 8.2 to 1 at December 31, 2025, compared to 7.8 to 1 at December 31, 2024.

Ceded Reinsurance

In the normal course of business, our insurance and mortgage insurance operations cede a portion of their premium on a quota share or excess of loss basis through treaty or facultative reinsurance agreements. Our reinsurance operations also obtain reinsurance whereby another reinsurer contractually agrees to indemnify it for all or a portion of the reinsurance risks underwritten by our reinsurance operations. Such arrangements, where one reinsurer provides reinsurance to another reinsurer, are usually referred to as “retrocessional reinsurance” arrangements. In addition, our reinsurance subsidiaries participate in “common account” retrocessional arrangements for certain pro rata treaties. Such arrangements reduce the effect of individual or aggregate losses to all companies participating on such treaties, including the reinsurers, such as our reinsurance operations, and the ceding company. Estimating reinsurance recoverables can be more subjective than estimating the

underlying reserves for losses and loss adjustment expenses as discussed above in “—Loss Reserves.” In particular, reinsurance recoverables may be affected by deemed inuring reinsurance, industry losses reported by various statistical reporting services, and other factors. Reinsurance recoverables are recorded as assets, predicated on the reinsurers’ ability to meet their obligations under the reinsurance agreements. If the reinsurers are unable to satisfy their obligations under the agreements, our insurance or reinsurance operations would be liable for such defaulted amounts.

The availability and cost of reinsurance and retrocessional protection is subject to market conditions, which are beyond our control. Although we believe that our insurance and reinsurance operations have been successful in obtaining adequate reinsurance and retrocessional protection, it is not certain that they will be able to continue to obtain adequate protection at cost effective levels. As a result of such market conditions and other factors, our insurance, reinsurance and mortgage operations may not be able to successfully mitigate risk through reinsurance and retrocessional arrangements and may lead to increased volatility in our results of operations in future periods. See Item 1A, “Risk Factors—Risks Relating to Our Industry, Business and Operations—The failure of any of the loss limitation methods we employ could have a material adverse effect on our financial condition or results of operations.”

For purposes of managing risk, we reinsure a portion of our exposures, paying to reinsurers a part of the premiums received on the policies we write, and we may also use retrocessional protection. On a consolidated basis, ceded premiums written represented 28.0% of gross premiums written for 2025, compared to 26.9% for 2024. We monitor the financial condition of our reinsurers and attempt to place coverages only with substantial, financially sound carriers. If the financial condition of our reinsurers or retrocessionaires deteriorates, resulting in an impairment of their ability to make payments, we will be responsible for probable losses resulting from our inability to collect amounts due from such parties, as appropriate. We evaluate the credit worthiness of all the reinsurers to which we cede business. We report reinsurance recoverables net of an allowance for expected credit loss. The allowance is based upon our ongoing review of amounts outstanding, the financial condition of our reinsurers, amounts and form of collateral obtained and other relevant factors. A ratings based probability-of-default and loss-given-default methodology is used to estimate the allowance for expected credit loss. See Item 1A, “Risk Factors—Risks Relating to Our Industry, Business and Operations—We are exposed to credit risk in certain of our business operations” and “Financial Condition, Liquidity and Capital Resources” for further details.

We have entered into various aggregate excess of loss reinsurance agreements with various special purpose reinsurance companies domiciled in Bermuda. These are special purpose variable interest entities that are not consolidated in our financial results because we do not have the unilateral power to direct those activities that are significant to its economic performance. Seenote 12, “Variable Interest Entities” to our consolidated financial statements in Item 8 for additional information.

Premium Revenues and Related Expenses

Insurance premiums written are generally recorded at the policy inception and are primarily earned on a pro rata basis over the terms of the policies for all products, usually 12 months. Premiums written include estimates in our insurance operations’ programs, specialty lines, collateral protection business and for participation in involuntary pools. Such premium estimates are derived from multiple sources which include the historical experience of the underlying business, similar business and available industry information. Unearned premium reserves represent the portion of premiums written that relates to the unexpired terms of in-force insurance policies.

Reinsurance premiums written include amounts reported by brokers and ceding companies, supplemented by our own estimates of premiums where reports have not been received. The determination of premium estimates requires a review of our experience with the ceding companies, familiarity with each market, the timing of the reported information, an analysis and understanding of the characteristics of each line of business, and management’s judgment of the impact of various factors, including premium or loss trends, on the volume of business written and ceded to us. On an ongoing basis, our underwriters review the amounts reported by these third parties for reasonableness based on their experience and knowledge of the subject class of business, taking into account our historical experience with the brokers or ceding companies. In addition, reinsurance contracts under which we assume business generally contain specific provisions which allow us to perform audits of the ceding company to ensure compliance with the terms and conditions of the contract, including accurate and timely reporting of information. Based on a review of all available information, management establishes premium estimates where reports have not been received. Premium estimates are updated when new information is received and differences between such estimates and actual amounts are recorded in the period in which estimates are changed or the actual amounts are determined. Premiums written are recorded based on the type of contracts we write. Premiums on our excess of loss and pro rata reinsurance contracts are estimated when the business is underwritten. For excess of loss contracts, premiums are recorded as written based on the terms of the

contract. Estimates of premiums written under pro rata contracts are recorded in the period in which the underlying risks incept and are based on information provided by the brokers and the ceding companies. For multi-year reinsurance treaties which are payable in annual installments, generally, only the initial annual installment is included as premiums written at policy inception due to the ability of the reinsured to commute or cancel coverage during the term of the policy. The remaining annual installments are included as premiums written at each successive anniversary date within the multi-year term.

Reinstatement premiums for our insurance and reinsurance operations are recognized at the time a loss event occurs, where coverage limits for the remaining life of the contract are reinstated under pre-defined contract terms. Reinstatement premiums, if obligatory, are fully earned when recognized. The accrual of reinstatement premiums is based on an estimate of losses and loss adjustment expenses, which reflects management’s judgment, as described above in “—Loss Reserves.”

The amount of reinsurance premium estimates included in premiums receivable and the amount of related acquisition expenses by type of business were as follows at December 31, 2025:

Premium estimates are reviewed by management at least quarterly. Such review includes a comparison of actual reported premiums to expected ultimate premiums along with a review of the aging and collection of premium estimates. Based on management’s review, the appropriateness of the premium estimates is evaluated, and any adjustment to these estimates is recorded in the period in which it becomes known. Adjustments to premium estimates could be material and such adjustments could directly and significantly impact earnings favorably or unfavorably in the period they are determined because the estimated premium may be fully or substantially earned.

A significant portion of amounts included as premiums receivable, which represent estimated premiums written, net of commissions, are not currently due based on the terms of the underlying contracts. Based on currently available information, we report premiums receivable net of an allowance for expected credit loss. We monitor credit risk associated with premiums receivable through our ongoing review of amounts outstanding, aging of the receivable, historical data and counterparty financial strength measures.

Reinsurance premiums assumed, irrespective of the class of business, are generally earned on a pro rata basis over the terms of the underlying policies or reinsurance contracts. Contracts and policies written on a “losses occurring” basis cover claims that may occur during the term of the contract or policy, which is typically 12 months. Accordingly, the premium is earned evenly over the term. Contracts which are written on a “risks attaching” basis cover claims which attach to the underlying insurance policies written during the terms of such contracts. Premiums earned on such contracts usually extend beyond the original term of the reinsurance contract, typically resulting in recognition of premiums earned in proportion to the period of risk coverage.

Certain of our reinsurance contracts include provisions that adjust premiums or acquisition expenses based upon the experience under the contracts. Premiums written and earned, as well as related acquisition expenses, are recorded based upon the projected experience under such contracts.

Retroactive reinsurance reimburses a ceding company for liabilities incurred as a result of past insurable events covered by the underlying policies reinsured. In certain instances, reinsurance contracts cover losses both on a prospective basis and on a retroactive basis and, accordingly, we bifurcate the prospective and retrospective elements of these reinsurance contracts and accounts for each element separately where practical. Underwriting income generated in connection with retroactive reinsurance contracts is deferred and amortized into income over the settlement period while losses are charged to income immediately. Subsequent changes in estimated amount or timing of cash flows under such retroactive reinsurance contracts are accounted for by adjusting the previously deferred amount to the balance that would have existed had the revised estimate been available at the inception of the reinsurance transaction, with a corresponding charge or credit to income.

Mortgage guaranty insurance policies are contracts that are generally non-cancelable by the insurer, are renewable at a fixed price, and provide for payment of premiums on a monthly, annual or single basis. Upon renewal, we are not able to re-underwrite or re-price our policies. Consistent with industry accounting practices, premiums written on a monthly basis are earned as coverage is provided. Premiums written on an annual basis are amortized on a monthly pro rata basis over the year of coverage. Primary mortgage

insurance premiums written on policies covering more than one year are referred to as single premiums. A portion of the revenue from single premiums is recognized in premiums earned in the current period, and the remaining portion is deferred as unearned premiums and earned over the estimated expiration of risk of the policy. If single premium policies related to insured loans are canceled for any reason and the policy is a non-refundable product, the remaining unearned premium related to each canceled policy is recognized as earned premium upon notification of the cancellation.

Unearned premiums represent the portion of premiums written that is applicable to the estimated unexpired risk of insured loans. A portion of premium payments may be refundable if the insured cancels coverage, which generally occurs when the loan is repaid, the loan amortizes to a sufficiently low amount to trigger a lender permitted or legally required cancellation, or the value of the property has increased sufficiently in accordance with the terms of the contract. Premium refunds reduce premiums earned in the consolidated statements of income. Generally, only unearned premiums are refundable.

Acquisition costs that are directly related and incremental to the successful acquisition or renewal of business are deferred and amortized based on the type of contract. For property and casualty insurance and reinsurance contracts, deferred acquisition costs are amortized over the period in which the related premiums are earned. Consistent with mortgage insurance industry accounting practice, amortization of acquisition costs related to the mortgage insurance contracts for each underwriting year’s book of business is recorded in proportion to estimated gross profits. Estimated gross profits are comprised of earned premiums and losses and loss adjustment expenses. For each underwriting year, we estimate the rate of amortization to reflect actual experience and any changes to persistency or loss development.

Acquisition expenses and other expenses related to our underwriting operations that vary with, and are directly related to, the successful acquisition or renewal of business are deferred and amortized based on the type of contract. Our insurance and reinsurance operations capitalize incremental direct external costs that result from acquiring a contract but do not capitalize salaries, benefits and other internal underwriting costs. For our mortgage insurance operations, which include a substantial direct sales force, both external and certain internal direct costs are deferred and amortized. Deferred acquisition costs are carried at their estimated realizable value and take into account anticipated losses and loss adjustment expenses, based on historical and current experience, and anticipated investment income.

A premium deficiency occurs if the sum of anticipated losses and loss adjustment expenses, unamortized acquisition costs and maintenance costs and anticipated investment income exceed unearned premiums. A premium deficiency reserve (“PDR”) is recorded by charging any unamortized acquisition costs to expense to the extent required in order to eliminate the deficiency. If the premium deficiency exceeds unamortized acquisition costs then a liability is accrued for the excess deficiency.

To assess the need for a PDR on our mortgage exposures, we develop loss projections based on modeled loan defaults related to our current policies in force. This projection is based on recent trends in default experience, severity and rates of defaulted loans moving to claim, as well as recent trends in the rate at which loans are prepaid, and incorporates anticipated interest income. Evaluating the expected profitability of our existing mortgage insurance business and the need for a PDR for our mortgage business involves significant reliance upon assumptions and estimates with regard to the likelihood, magnitude and timing of potential losses and premium revenues. The models, assumptions and estimates we use to evaluate the need for a PDR may prove to be inaccurate, especially during an extended economic downturn or a period of extreme market volatility and uncertainty.

No premium deficiency charges were recorded by us during 2025 or 2024.

Net Deferred Income Tax Assets Measurement

Deferred income tax assets and liabilities reflect temporary differences based on enacted tax rates between the carrying amounts of assets and liabilities for financial reporting and income tax purposes. We determine deferred tax assets and liabilities separately for each tax-paying component (an individual entity or group of entities that is consolidated for tax purposes) in each tax jurisdiction. There may be changes in tax laws where we transact business that impact our deferred tax assets and liabilities. The most significant deferred income tax assets recognized relate to goodwill and intangible assets. With respect to our Bermuda entities, we estimated the fair value of its intangible assets using discounted cash flow (“DCF”) models. The significant assumptions utilized in the DCF models included the future revenue and profits expected to be generated by the identifiable intangible assets and the discount rates. See note 15, “Income Taxes” to our consolidated financial statements in Item 8 for disclosures concerning our Company’s deferred income tax asset.

Fair Value Measurements

We review our securities measured at fair value and discuss the proper classification of such investments with investment advisors and others. Seenote 10, “Fair Value,” to our consolidated financial statements in Item 8 for a summary of our financial assets and liabilities measured at fair value at December 31, 2025 by valuation hierarchy.

Reclassifications

We have reclassified the presentation of certain prior year information to conform to the current presentation. Such reclassifications had no effect on our net income, shareholders’ equity or cash flows.

Significant Accounting Pronouncements

For all other significant accounting policies seenote 3, “Significant Accounting Policies” andnote 3(u), “Recent Accounting Pronouncements” to our consolidated financial statements in Item 8 for disclosures concerning our companies significant accounting policies and recent accounting pronouncements.