White Mountains’s share-based incentive compensation plans are designed to incentivize key employees to maximize shareholder value over long periods of time. White Mountains believes that this is best pursued by utilizing a pay-for-performance program that closely aligns the financial interests of management with those of its shareholders while rewarding appropriate risk taking. White Mountains accomplishes this by emphasizing variable long-term compensation that is contingent on performance over a number of years rather than fixed entitlements. White Mountains expenses all its share-based compensation. As a result, White Mountains’s calculation of its owners’ returns includes the expense of all outstanding share-based compensation awards.

The WTM Incentive Plan provides for grants of various types of share-based and non-share-based incentive awards to key employees and directors of White Mountains. As of March 31, 2026 and 2025, White Mountains’s share-based incentive compensation awards consist of performance shares and restricted shares.

Performance shares are designed to reward employees for meeting company-wide performance targets. Performance shares are conditional grants of a specified maximum number of common shares or an equivalent amount of cash. Awards generally vest at the end of a three-year service period, are subject to the attainment of pre-specified performance goals and are valued based on the market value of common shares at the time awards are paid. Performance shares earned under the WTM Incentive Plan are typically paid in cash but may be paid in common shares. Compensation expense is recognized for the vested portion of the awards over the related service periods. The level of payout ranges from zero to two times the number of shares initially granted, depending on White Mountains’s financial performance. Performance shares become payable at the conclusion of a performance cycle (typically three years) if pre-defined financial targets are met.

The performance measure used for determining performance share payouts is the growth in compensation value per share (“CVPS”). Prior to 2025, CVPS was calculated as the average of the growth in adjusted book value per share and the growth in intrinsic value per share. Intrinsic value per share is calculated by adjusting White Mountains’s book value per share for differences between the book value of certain assets and liabilities and White Mountains’s estimate of their underlying intrinsic value. For calendar years beginning with 2025, White Mountains has replaced growth in adjusted book value per share with growth in book value per share in the calculation of CVPS. For example, for the 2024-2026 performance cycle, adjusted book value per share growth would be used in the calculation of CVPS for calendar year 2024, and book value per share growth would be used for calendar years 2025 and 2026.


	Three Months Ended March 31,
		2026	2025
$ in Millions			Target Performance Shares Outstanding	Accrued Expense		Target Performance Shares Outstanding	Accrued Expense
Beginning of period			32,416	$	73.2	34,859	$	71.1
Shares paid or expired (1)			(10,835)	(44.1)		(13,150)	(48.7)
New grants			9,615	—		10,645	—
Forfeitures and cancellations (2)			19	.5		38	.8
Expense recognized			—	13.0		—	.1
End of period			31,215	$	42.6	32,392	$	23.3

(1) WTM performance share payments for the 2023-2025 performance cycle were made in March 2026 at 184% of target. WTM performance share payments for the 2022-2024 performance cycle were made in March 2025 at 200% of target.

During the three months ended March 31, 2026, White Mountains granted 9,615 performance shares for the 2026-2028 performance cycle. During the three months ended March 31, 2025, White Mountains granted 10,645 performance shares for the 2025-2027 performance cycle.

For the 2023-2025 performance cycle, all performance shares earned were settled in cash. For the 2022-2024 performance cycle, the Company issued common shares for 30 performance shares earned, and all other performance shares earned were settled in cash. If all outstanding performance shares had vested on March 31, 2026, the total additional compensation cost to be recognized would have been $52.3 million, based on accrual factors as of March 31, 2026 (common share price and payout assumptions).


	March 31, 2026
$ in Millions	Target Performance Shares Outstanding	Accrued Expense
Performance cycle:
2024 – 2026	11,405	$	28.6
2025 – 2027	10,670	14.0
2026 – 2028	9,615	.6

Sub-total	31,690	43.2
Assumed forfeitures	(475)	(.6)
Total	31,215	$	42.6

For the 2026-2028 performance cycle, the targeted performance goal for full payment of outstanding performance shares granted under the WTM Incentive Plan is 11% average annual growth in CVPS. Average annual growth of 6% or less would result in no payout, and average annual growth of 16% or more would result in a payout of 200%.

Restricted shares are grants of a specified number of common shares that generally vest at the end of a 34-month service period. The following table presents the unrecognized compensation cost associated with the outstanding restricted share awards under the WTM Incentive Plan for the three months ended March 31, 2026 and 2025:


	Three Months Ended March 31,
		2026	2025
$ in Millions			Restricted Shares	Unamortized Issue Date Fair Value		Restricted Shares	Unamortized Issue Date Fair Value
Non-vested,
Beginning of period			32,910	$	21.0	35,390	$	19.9
Vested			(10,835)	—		(13,150)	—
Issued			9,615	21.3		10,645	19.5
Forfeited			—	—		—	—
Expense recognized			—	(4.1)		—	(3.8)
End of period			31,690	$	38.2	32,885	$	35.6