Business and Significant Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying Condensed Consolidated Financial Statements of Argo Group International Holdings, Inc. and its subsidiaries (“Argo Group,” “we,” “us,” “our” or the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Argo Group is an underwriter of specialty insurance products in the property and casualty market. On November 16, 2023, we merged with Brookfield Wealth Solutions Ltd. (formerly known as Brookfield Reinsurance Ltd.), which resulted in a change to the Company’s ownership (the “Merger”). As a result of the Merger, and overall strategic shift, the Company changed its internal segments in a manner that caused the composition of its reporting segments to change in the fourth quarter of 2024. The Company’s reporting segments were realigned to three reportable segments—Casualty Lines, Specialty Lines, and Run-off Lines. Previously, the Company reported its operations under U.S Operations, International Operations and Run-off Lines, which primarily consisted of other liability policies that were issued in the 1960s, 1970s and into the 1980s, as well as the former risk-management business. For additional segment information, refer to Note 13, “Segment Information.” The Company has recast all applicable periods for comparability. The preparation of interim financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. The major estimates reflected in our Condensed Consolidated Financial Statements include, but are not limited to, reserves for losses and loss adjustment expenses; reinsurance recoverables, including the reinsurance recoverables allowance for expected credit losses; fair value of investments and assessment of potential impairment, including the allowance for credit losses on fixed maturity securities; valuation of intangibles, including those identified as part of purchase accounting related to the Merger, and our deferred tax asset valuation allowance. Actual results could materially differ from those estimates. Certain financial information that is normally included in annual Condensed Consolidated Financial Statements, including certain financial statement footnotes, prepared in accordance with GAAP, is not required for interim reporting purposes and has been condensed or omitted. These statements should be read in conjunction with the Condensed Consolidated Financial Statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2024 filed with the Securities and Exchange Commission ("SEC") (the “2024 Form 10-K”). The interim financial information as of, and for the three months ended, March 31, 2025 and 2024 is unaudited. However, in the opinion of management, the interim information includes all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the results presented for the interim periods. The operating results for the interim periods are not necessarily indicative of the results to be expected for the full year. All material intercompany amounts have been eliminated in consolidation.
Reclassification	Certain reclassifications have been made to financial information presented for prior years to conform to the current year’s presentation.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements On December 14, 2023, the FASB issued Accounting Standards Update 2023-09—Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments improve income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures. The amendments in ASU 2023-09 are effective for fiscal years beginning after December 15, 2024. We are currently evaluating the requirements of ASU 2023-09. However, as they apply to disclosure requirements, the adoption of the standard is not anticipated to have a material impact on our profitability, financial position or cash flows. On November 4, 2024, the FASB issued Accounting Standards Update 2024-03—Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. Disaggregation of income statement expenses is to improve interim and annual disclosures about a public business entity’s expenses by requiring more detailed information in the notes to the financial statements about certain expense categories, including purchases of inventory, employee compensation, depreciation, amortization, and selling expenses. We expect to adopt ASU 2024-03 effective January 1, 2027 but the adoption will not affect our financial position or our results of operations, however, will result in additional disclosures.
Allowance for Credit Losses	Allowance for Credit Losses For fixed maturities with a decline in fair value below the amortized cost due to credit-related factors, an allowance is established for the difference between the estimated recoverable value and amortized cost with a corresponding charge to Net investment and other gains (losses) in the Condensed Consolidated Statements of Income (Loss). The allowance is limited to the difference between amortized cost and fair value. The estimated recoverable value is the present value of cash flows expected to be collected, as determined by management. The difference between fair value and amortized cost that is not associated with credit-related factors is recognized in the Condensed Consolidated Statements of Comprehensive Income (Loss). Accrued interest is excluded from the measurement of the allowance for credit losses. When determining if a credit loss has been incurred, we may consider the historical performance of the security, available market information and security specific considerations such as the priority payment of the security. In addition, inputs used in our analysis include, but are not limited to, credit ratings and downgrades, delinquency rates, missed scheduled interest or principal payments, purchase yields, underlying asset performance, collateral types, modeled default rates, modeled severity rates, call/prepayment rates, expected cash flows, industry concentrations, and potential or filed bankruptcies or restructurings. In cooperation with our investment managers, we evaluate for credit losses each quarter utilizing a bottom up review approach. At the security level, a determination is made as to whether a decline in fair value below the amortized cost basis is due to credit-related or noncredit-related factors. If we determine that all or a portion of a fixed maturity is uncollectible, the uncollectible amortized cost is written off with a corresponding reduction to the allowance for credit losses. If we collect cash flows that were previously written off, the recovery is recognized in Net investment and other gains (losses). We also consider whether we intend to sell an available-for-sale security or if it is more likely than not that we will be required to sell the security before recovery of its amortized cost. In these instances, a decline in fair value is recognized in Net investment and other gains (losses) in the Condensed Consolidated Statements of Income (Loss) based on the fair value of the security at the time of assessment, resulting in a new cost basis for the security.
Disclosures about Fair Value of Financial Instruments	Disclosures About Fair Value of Financial Instruments Cash. The carrying amount approximates fair value. Investment securities, mortgage loan and private loan investments, and short-term investments. See Note 3, “Investments,” for additional information. Premiums receivable and reinsurance recoverables on paid losses. The carrying value of current receivables and reinsurance recoverables on paid losses approximates fair value due to short-term nature. Debt. At March 31, 2025 and December 31, 2024, the fair value of our debt instruments is determined using both Level 1 and Level 2 inputs, as previously defined in Note 3, “Investments.” We receive fair value prices for similar financial instruments being traded in active markets. These prices are determined using observable market information such as publicly traded quoted prices, and trading prices for similar financial instruments actively being traded in the current market. We have reviewed the processes used by third-party providers for pricing these instruments and have determined that they result in fair values consistent with GAAP requirements. In addition, we review these prices for reasonableness, and have not adjusted any prices received from the third-party providers as of March 31, 2025 and December 31, 2024. A description of the valuation techniques we use to measure these liabilities at fair value is as follows: Senior Unsecured Fixed Rate Notes Level 1: •Our senior unsecured fixed rate notes are valued using Level 1 inputs. For these securities, we obtain fair value measurements from a third-party pricing service using quoted prices (unadjusted) in active markets at the reporting date. Junior Subordinated Debentures Level 2: •Our trust preferred debentures and subordinated debentures are typically valued using Level 2 inputs. For these securities, we obtain fair value measurements using quoted prices for similar securities being traded in active markets at the reporting date, as our specific debt instruments are less frequently traded.
Fair Value Measurement	Fair Value Measurements Fair value is the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurement assumes that the transaction to sell the asset or transfer the liability occurs in the principal market for the asset or liability, or in the absence of a principal market, the most advantageous market. Market participants are buyers and sellers in the principal (or most advantageous) market that are independent, knowledgeable, able to transact for the asset or liability and willing to transfer the asset or liability. Valuation techniques consistent with the market approach, income approach and/or cost approach are used to measure fair value. The inputs of these valuation techniques are categorized into three levels. •Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that can be accessed at the reporting date. We define actively traded as a security that has traded in the past seven days. •Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. We receive one quote per instrument for Level 2 inputs. •Level 3 inputs are unobservable inputs. Unobservable inputs reflect our own judgments about the assumptions market participants would use in pricing the asset or liability based on the best information available in the circumstances. Significant increases (decreases) in those inputs in isolation could result in a significantly lower (higher) fair value measurement. To validate the fair value of investments in the Company’s Condensed Consolidated Financial Statements, we receive prices from multiple sources including third-party pricing services and our outside investment managers. Through a comparative analysis, the Company validates the reasonableness of its valuations. These prices are determined using observable market information such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the security’s terms and conditions, among other things. We have reviewed the processes used by the third-party providers for pricing the securities and have determined that these processes result in fair values consistent with GAAP requirements. In addition, we review these prices for reasonableness, and have not adjusted any prices received from the third-party providers as of March 31, 2025 and December 31, 2024. A description of the valuation techniques we use to measure assets at fair value is as follows: Fixed Maturities (Available-for-Sale) Levels 1 and 2: •United States Treasury securities are typically valued using Level 1 inputs. For these securities, we obtain fair value measurements from third-party pricing services using quoted prices (unadjusted) in active markets at the reporting date. •United States Government agencies, non-U.S. Government securities, obligations of states and political subdivisions, credit securities and foreign denominated government and credit securities are reported at fair value using Level 2 inputs. For these securities, we obtain fair value measurements from third-party pricing services. Observable data may include dealer quotes, market spreads, yield curves, live trading levels, trade execution data, credit information and the security’s terms and conditions, among other things. •Asset and mortgage-backed securities and collateralized loan obligations are reported at fair value using Level 2 inputs. For these securities, we obtain fair value measurements from third-party pricing services. Observable data may include dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the security’s terms and conditions, among other things. Fixed Maturities (Available-for-Sale) Level 3: We own term loans and asset-back securities that are valued using unobservable inputs. Equity Securities Level 1: For these securities, we obtain fair value measurements from a third-party pricing service using quoted prices (unadjusted) in active markets at the reporting date. Equity Securities Level 3: We own certain equity securities that are reported at fair value using Level 3 inputs. The valuation techniques for these securities include the following: •Fair value measurements for an investment in an equity fund obtained by applying final prices provided by the administrator of the fund, which is based upon certain estimates and assumptions. •Fair value measurements from brokers and independent valuation services, both based upon estimates, assumptions and other unobservable inputs. Short-term Investments: Short-term investments are principally reported at fair value using Level 1 inputs, with the exception of short-term corporate and governmental bonds reported at fair value using Level 2 inputs as described in the fixed maturities section above. Values for the investments categorized as Level 1 are obtained from various financial institutions as of the reporting date. Other investments: Other investments include private securities for which we have elected the fair value option of accounting, and are valued using unobservable Level 3 inputs. Derivative assets: As a result of the Company’s commutation of the assumed reinsurance agreement with Riverstone Holdings Limited, the Company classified the ceded reserves on the Malta business as a derivative in accordance with ASC 815. As the ceded reserves are shorter term in nature, management has concluded that the fair value is equivalent to its carrying value, resulting in no impact to earnings. Derivative liabilities: We enter into foreign currency forward contracts to hedge our investment exposure to foreign currencies. These derivatives are carried at fair value using Level 2 inputs, primarily observable foreign exchange rates at the end of the period.

Business and Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The accompanying Condensed Consolidated Financial Statements of Argo Group International Holdings, Inc. and its subsidiaries (“Argo Group,” “we,” “us,” “our” or the “Company”) have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information and with the instructions for Form 10-Q and Article 10 of Regulation S-X. Argo Group is an underwriter of specialty insurance products in the property and casualty market.

On November 16, 2023, we merged with Brookfield Wealth Solutions Ltd. (formerly known as Brookfield Reinsurance Ltd.), which resulted in a change to the Company’s ownership (the “Merger”). As a result of the Merger, and overall strategic shift, the Company changed its internal segments in a manner that caused the composition of its reporting segments to change in the fourth quarter of 2024. The Company’s reporting segments were realigned to three reportable segments—Casualty Lines, Specialty Lines, and Run-off Lines. Previously, the Company reported its operations under U.S Operations, International Operations and Run-off Lines, which primarily consisted of other liability policies that were issued in the 1960s, 1970s and into the 1980s, as well as the former risk-management business. For additional segment information, refer to Note 13, “Segment Information.” The Company has recast all applicable periods for comparability.

The preparation of interim financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of revenues and expenses during the reporting period. The major estimates reflected in our Condensed Consolidated Financial Statements include, but are not limited to, reserves for losses and loss adjustment expenses; reinsurance recoverables, including the reinsurance recoverables allowance for expected credit losses; fair value of investments and assessment of potential impairment, including the allowance for credit losses on fixed maturity securities; valuation of intangibles, including those identified as part of purchase accounting related to the Merger, and our deferred tax asset valuation allowance. Actual results could materially differ from those estimates. Certain financial information that is normally included in annual Condensed Consolidated Financial Statements, including certain financial statement footnotes, prepared in accordance with GAAP, is not required for interim reporting purposes and has been condensed or omitted. These statements should be read in conjunction with the Condensed Consolidated Financial Statements and notes thereto included in our Annual Report on Form 10-K for the year ended December 31, 2024 filed with the Securities and Exchange Commission ("SEC") (the “2024 Form 10-K”).

The interim financial information as of, and for the three months ended, March 31, 2025 and 2024 is unaudited. However, in the opinion of management, the interim information includes all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the results presented for the interim periods. The operating results for the interim periods are not necessarily indicative of the results to be expected for the full year. All material intercompany amounts have been eliminated in consolidation.

Reclassification

Certain reclassifications have been made to financial information presented for prior years to conform to the current year’s presentation.

Recently Issued Accounting Pronouncements

On December 14, 2023, the FASB issued Accounting Standards Update 2023-09—Income Taxes (Topic 740): Improvements to Income Tax Disclosures. The amendments improve income tax disclosures by requiring (1) consistent categories and greater disaggregation of information in the rate reconciliation and (2) income taxes paid disaggregated by jurisdiction. It also includes certain other amendments to improve the effectiveness of income tax disclosures.

The amendments in ASU 2023-09 are effective for fiscal years beginning after December 15, 2024.

We are currently evaluating the requirements of ASU 2023-09. However, as they apply to disclosure requirements, the adoption of the standard is not anticipated to have a material impact on our profitability, financial position or cash flows.

On November 4, 2024, the FASB issued Accounting Standards Update 2024-03—Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. Disaggregation of income statement expenses is to improve interim and annual disclosures about a public business entity’s expenses by requiring more detailed information in the notes to the financial statements about certain expense categories, including purchases of inventory, employee compensation, depreciation, amortization, and selling expenses. We expect to adopt ASU 2024-03 effective January 1, 2027 but the adoption will not affect our financial position or our results of operations, however, will result in additional disclosures.

Allowance for Credit Losses

For fixed maturities with a decline in fair value below the amortized cost due to credit-related factors, an allowance is established for the difference between the estimated recoverable value and amortized cost with a corresponding charge to Net investment and other gains (losses) in the Condensed Consolidated Statements of Income (Loss). The allowance is limited to the difference between amortized cost and fair value. The estimated recoverable value is the present value of cash flows expected to be collected, as determined by management. The difference between fair value and amortized cost that is not associated with credit-related factors is recognized in the Condensed Consolidated Statements of Comprehensive Income (Loss). Accrued interest is excluded from the measurement of the allowance for credit losses.

When determining if a credit loss has been incurred, we may consider the historical performance of the security, available market information and security specific considerations such as the priority payment of the security. In addition, inputs used in our analysis include, but are not limited to, credit ratings and downgrades, delinquency rates, missed scheduled interest or principal payments, purchase yields, underlying asset performance, collateral types, modeled default rates, modeled severity rates, call/prepayment rates, expected cash flows, industry concentrations, and potential or filed bankruptcies or restructurings.

In cooperation with our investment managers, we evaluate for credit losses each quarter utilizing a bottom up review approach. At the security level, a determination is made as to whether a decline in fair value below the amortized cost basis is due to credit-related or noncredit-related factors. If we determine that all or a portion of a fixed maturity is uncollectible, the uncollectible amortized cost is written off with a corresponding reduction to the allowance for credit losses. If we collect cash flows that were previously written off, the recovery is recognized in Net investment and other gains (losses). We also consider whether we intend to sell an available-for-sale security or if it is more likely than not that we will be required to sell the security before recovery of its amortized cost. In these instances, a decline in fair value is recognized in Net investment and other gains (losses) in the Condensed Consolidated Statements of Income (Loss) based on the fair value of the security at the time of assessment, resulting in a new cost basis for the security.

Disclosures about Fair Value of Financial Instruments

Disclosures About Fair Value of Financial Instruments

Cash. The carrying amount approximates fair value.

Investment securities, mortgage loan and private loan investments, and short-term investments. See Note 3, “Investments,” for additional information.

Premiums receivable and reinsurance recoverables on paid losses. The carrying value of current receivables and reinsurance recoverables on paid losses approximates fair value due to short-term nature.

Debt. At March 31, 2025 and December 31, 2024, the fair value of our debt instruments is determined using both Level 1 and Level 2 inputs, as previously defined in Note 3, “Investments.”

We receive fair value prices for similar financial instruments being traded in active markets. These prices are determined using observable market information such as publicly traded quoted prices, and trading prices for similar financial instruments actively being traded in the current market. We have reviewed the processes used by third-party providers for pricing these instruments and have determined that they result in fair values consistent with GAAP requirements. In addition, we review these prices for reasonableness, and have not adjusted any prices received from the third-party providers as of March 31, 2025 and December 31, 2024. A description of the valuation techniques we use to measure these liabilities at fair value is as follows:

Senior Unsecured Fixed Rate Notes Level 1:

•Our senior unsecured fixed rate notes are valued using Level 1 inputs. For these securities, we obtain fair value measurements from a third-party pricing service using quoted prices (unadjusted) in active markets at the reporting date.

Junior Subordinated Debentures Level 2:

•Our trust preferred debentures and subordinated debentures are typically valued using Level 2 inputs. For these securities, we obtain fair value measurements using quoted prices for similar securities being traded in active markets at the reporting date, as our specific debt instruments are less frequently traded.

Fair Value Measurement

Fair Value Measurements

Fair value is the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Fair value measurement assumes that the transaction to sell the asset or transfer the liability occurs in the principal market for the asset or liability, or in the absence of a principal market, the most advantageous market. Market participants are buyers and sellers in the principal (or most advantageous) market that are independent, knowledgeable, able to transact for the asset or liability and willing to transfer the asset or liability.

Valuation techniques consistent with the market approach, income approach and/or cost approach are used to measure fair value. The inputs of these valuation techniques are categorized into three levels.

•Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that can be accessed at the reporting date. We define actively traded as a security that has traded in the past seven days.

•Level 2 inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. We receive one quote per instrument for Level 2 inputs.

•Level 3 inputs are unobservable inputs. Unobservable inputs reflect our own judgments about the assumptions market participants would use in pricing the asset or liability based on the best information available in the circumstances. Significant increases (decreases) in those inputs in isolation could result in a significantly lower (higher) fair value measurement.

To validate the fair value of investments in the Company’s Condensed Consolidated Financial Statements, we receive prices from multiple sources including third-party pricing services and our outside investment managers. Through a comparative analysis, the Company validates the reasonableness of its valuations. These prices are determined using observable market information such as dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the security’s terms and conditions, among other things. We have reviewed the processes used by the third-party providers for pricing the securities and have determined that these processes result in fair values consistent with GAAP requirements. In addition, we review these prices for reasonableness, and have not adjusted any prices received from the third-party providers as of March 31, 2025 and December 31, 2024. A description of the valuation techniques we use to measure assets at fair value is as follows:

Fixed Maturities (Available-for-Sale) Levels 1 and 2:

•United States Treasury securities are typically valued using Level 1 inputs. For these securities, we obtain fair value measurements from third-party pricing services using quoted prices (unadjusted) in active markets at the reporting date.

•United States Government agencies, non-U.S. Government securities, obligations of states and political subdivisions, credit securities and foreign denominated government and credit securities are reported at fair value using Level 2 inputs. For these securities, we obtain fair value measurements from third-party pricing services. Observable data may include dealer quotes, market spreads, yield curves, live trading levels, trade execution data, credit information and the security’s terms and conditions, among other things.

•Asset and mortgage-backed securities and collateralized loan obligations are reported at fair value using Level 2 inputs. For these securities, we obtain fair value measurements from third-party pricing services. Observable data may include dealer quotes, market spreads, cash flows, yield curves, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the security’s terms and conditions, among other things.

Fixed Maturities (Available-for-Sale) Level 3: We own term loans and asset-back securities that are valued using unobservable inputs.

Equity Securities Level 1: For these securities, we obtain fair value measurements from a third-party pricing service using quoted prices (unadjusted) in active markets at the reporting date.

Equity Securities Level 3: We own certain equity securities that are reported at fair value using Level 3 inputs. The valuation techniques for these securities include the following:

•Fair value measurements for an investment in an equity fund obtained by applying final prices provided by the administrator of the fund, which is based upon certain estimates and assumptions.

•Fair value measurements from brokers and independent valuation services, both based upon estimates, assumptions and other unobservable inputs.

Short-term Investments: Short-term investments are principally reported at fair value using Level 1 inputs, with the exception of short-term corporate and governmental bonds reported at fair value using Level 2 inputs as described in the fixed maturities section above. Values for the investments categorized as Level 1 are obtained from various financial institutions as of the reporting date.

Other investments: Other investments include private securities for which we have elected the fair value option of accounting, and are valued using unobservable Level 3 inputs.

Derivative assets: As a result of the Company’s commutation of the assumed reinsurance agreement with Riverstone Holdings Limited, the Company classified the ceded reserves on the Malta business as a derivative in accordance with ASC 815. As the ceded reserves are shorter term in nature, management has concluded that the fair value is equivalent to its carrying value, resulting in no impact to earnings.

Derivative liabilities: We enter into foreign currency forward contracts to hedge our investment exposure to foreign currencies. These derivatives are carried at fair value using Level 2 inputs, primarily observable foreign exchange rates at the end of the period.