WHITE MOUNTAINS INSURANCE GROUP LTD

This report includes five non-GAAP financial measures that have been reconciled with their most comparable GAAP financial measures.

Adjusted book value per share

Adjusted book value per share is a non-GAAP financial measure which is derived by adjusting (i) the GAAP book value per share numerator and (ii) the common shares outstanding denominator, as described below.

The GAAP book value per share numerator is adjusted (i) to add back the unearned premium reserve, net of deferred acquisition costs, at HG Global and (ii) to include a discount for the time value of money arising from the modeled timing of cash payments of principal and interest on the BAM Surplus Notes.

The value of HG Global’s unearned premium reserve, net of deferred acquisition costs, was $195 million, $179 million and $159 million as of December 31, 2023, 2022 and 2021, respectively.

Under GAAP, White Mountains is required to carry the BAM Surplus Notes, including accrued interest, at nominal value with no consideration for time value of money. Based on a debt service model that forecasts operating results for BAM through maturity of the BAM Surplus Notes, the present value of the BAM Surplus Notes, including accrued interest and using an 8.0% discount rate, was estimated to be $91 million, $98 million and $130 million less than the nominal GAAP carrying values as of December 31, 2023, 2022 and 2021, respectively.

White Mountains believes these adjustments are useful to management and investors in analyzing the intrinsic value of HG Global, including the value of the BAM Surplus Notes and the value of the in-force business at HG Re, HG Global’s reinsurance subsidiary.

The denominator used in the calculation of adjusted book value per share equals the number of common shares outstanding adjusted to exclude unearned restricted common shares, the compensation cost of which, at the date of calculation, has yet to be amortized. Restricted common shares are earned on a straight-line basis over their vesting periods. The reconciliation of GAAP book value per share to adjusted book value per share is included on page 45.

Kudu’s EBITDA and Kudu’s adjusted EBITDA

Kudu's EBITDA and adjusted EBITDA are non-GAAP financial measures. EBITDA is a non-GAAP financial measure that excludes interest expense on debt, income tax (expense) benefit, depreciation and amortization of other intangible assets from GAAP net income (loss). Adjusted EBITDA is a non-GAAP financial measure that excludes certain other items in GAAP net income (loss) in addition to those excluded from EBITDA. The adjustments relate to (i) net realized and unrealized investment gains (losses) on Kudu's Participation Contracts, (ii) non-cash equity-based compensation expense and (iii) transaction expenses. A description of each adjustment follows:

•Net realized and unrealized investment gains (losses) - Represents net unrealized investment gains and losses on Kudu’s Participation Contracts, which are recorded at fair value under GAAP, and net realized investment gains and losses on Kudu’s Participation Contracts sold during the period.

•Non-cash equity-based compensation expense- Represents non-cash expenses related to Kudu’s management compensation that are settled with equity units in Kudu.

•Transaction expenses - Represents costs directly related to Kudu’s mergers and acquisitions activity, such as external lawyer, banker, consulting and placement agent fees, which are not capitalized and are expensed under GAAP.

White Mountains believes that these non-GAAP financial measures are useful to management and investors in evaluating Kudu’s performance. The reconciliation of Kudu’s GAAP net income (loss) to EBITDA and adjusted EBITDA is included on page 59.

Total consolidated portfolio return excluding MediaAlpha

Total consolidated portfolio return excluding MediaAlpha is a non-GAAP financial measure that removes the net investment income and net realized and unrealized investment gains (losses) from White Mountains’s investment in MediaAlpha. White Mountains believes this measure to be useful to management and investors by showing the underlying performance of White Mountains’s investment portfolio without regard to MediaAlpha.

The following table presents return reconciliations from GAAP to the reported percentages:

Total adjusted capital

Total capital at White Mountains is comprised of White Mountains’s common shareholders’ equity, debt and noncontrolling interests other than noncontrolling interests attributable to BAM. Total adjusted capital is a non-GAAP financial measure, which is derived by adjusting total capital (i) to include a discount for the time value of money arising from the expected timing of cash payments of principal and interest on the BAM Surplus Notes and (ii) to add back the unearned premium reserve, net of deferred acquisition costs, at HG Global. The reconciliation of total capital to total adjusted capital is included on page 70.