SCHEDULE I SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES

12 Months Ended

Dec. 31, 2022

SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties [Abstract]

Schedule I - Summary of Investments-Other Than Investments in Related Parties

WHITE MOUNTAINS INSURANCE GROUP, LTD.

SUMMARY OF INVESTMENTS—OTHER THAN

INVESTMENTS IN RELATED PARTIES

At December 31, 2022

Millions	Cost		Carrying Value		Fair Value
Fixed maturity investments:
U.S. Government and agency obligations	$	216.6	$	206.4	$	206.4
Debt securities issued by corporations	1,098.3		1,018.8		1,018.8
Municipal obligations	281.6		258.6		258.6
Mortgage and asset-backed securities	288.7		254.2		254.2
Collateralized loan obligations	190.8		182.9		182.9
Total fixed maturity investments	2,076.0		1,920.9		1,920.9
Short-term investments	925.2		924.1		924.1
Investment in MediaAlpha	—		168.6		168.6
Common equity securities:
Common equity securities - Industrial, Miscellaneous, and Other	324.3		334.6		334.6
Common equity securities - Exchange traded funds	336.3		333.8		333.8
Total common equity securities	660.6		668.4		668.4
Other long-term investments	1,340.8		1,488.0		1,488.0
Total investments	$	5,002.6	$	5,170.0	$	5,170.0