HANOVER INSURANCE GROUP, INC. New Standards Disclosure

O. New Accounting Pronouncements

Recently Implemented Standards

In December 2023, the Financial Accounting Standards Board (“FASB”) issued ASC Update No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures. This Update requires entities to disclose an annual tabular rate reconciliation, using both percentages and currency amounts, broken out into specific categories, to the extent those items exceed a specified threshold. In addition, all entities are required to disclose annual income taxes paid, net of refunds received, disaggregated by federal, state, and foreign jurisdictions, and for individual jurisdictions when the amount is at least five percent of total income tax payments, net of refunds received. This Update was effective for annual reporting periods beginning after December 15, 2024. The Company implemented this guidance on a prospective basis and it did not have a material effect on its financial position or results of operations, as the Update is disclosure related.

In November 2023, the FASB issued ASC Update No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures. This Update requires entities to disclose significant segment expenses and other segment items on an annual and interim basis, and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. Additionally, it requires entities to disclose the title and position of the Chief Operating Decision Maker (“CODM”), and an explanation of how the CODM uses the reported measures of segment profit or loss. The Update does not change how entities identify operating segments, aggregate them, or apply the quantitative thresholds to determine reportable segments. This Update was effective for annual reporting periods beginning after December 15, 2023, and interim reporting periods beginning after December 15, 2024. The Company implemented this guidance effective January 1, 2024, on a retrospective basis, and it did not have a material effect on its financial position or results of operations, as the Update is disclosure related.

Recently Issued Standards

In September 2025, the FASB issued ASC Update No. 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. This Update eliminates the traditional three-stage sequential software development model (preliminary, application development, and post-implementation) and instead requires capitalization to begin once management has authorized and commits funding to each software project, and completion of the software for its intended use is probable. The guidance states that the “probable-to-complete” recognition threshold is not met until significant development uncertainty has been resolved. Additionally, disclosure requirements for internal-use software have been updated to align with those for property, plant, and equipment under ASC 360-10, Property, Plant and Equipment - Overall, regardless of whether the software is classified as intangible or tangible. This Update is effective for interim and annual reporting periods beginning after December 15, 2027, with early adoption permitted. This guidance may be implemented either on a prospective, modified, or retrospective basis. The Company is currently assessing the impact of this guidance to its financial position and results of operations.

In November 2024, the FASB issued ASC Update No. 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40). This Update requires entities to disclose, at each interim and annual reporting period, specified information about certain costs and expenses in the notes to financial statements. Entities must disclose the amounts, in a tabular format, of relevant expense captions presented on the face of the income statement within continuing operations that contain expenses associated with employee compensation, depreciation, and intangible asset amortization. Additionally, the Update requires qualitative disclosure of amounts remaining in relevant expense captions that are not separately disaggregated quantitatively, and the disclosure of total selling expenses, among other items. This Update is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods, as clarified in ASC Update No. 2025-01, beginning after December 15, 2027, with early adoption permitted. This guidance may be implemented either on a prospective or retrospective basis. The Company does not expect implementation of this guidance to have a material effect on its financial position or results of operations, as the Update is disclosure related.