WHITE MOUNTAINS INSURANCE GROUP LTD

White Mountains Insurance Group, Ltd. (the “Company” or the “Registrant”) is an exempted Bermuda limited liability company whose principal businesses are conducted through its subsidiaries and affiliates. Within this report, the term “White Mountains” is used to refer to one or more entities within the consolidated organization, as the context requires. The Company’s headquarters is located at 26 Reid Street, Hamilton, Bermuda HM 11, its principal executive office is located at 23 South Main Street, Suite 3B, Hanover, New Hampshire 03755-2053 and its registered office is located at Clarendon House, 2 Church Street, Hamilton, Bermuda HM 11. The Company’s website is located atwww.whitemountains.com. The information contained on White Mountains’s website is not incorporated by reference into, and is not a part of, this report.

White Mountains is engaged in the business of making opportunistic and value-oriented acquisitions of businesses and assets in the insurance, financial services and related sectors, operating these businesses and assets through its subsidiaries and, if and when attractive exit valuations become available, disposing of these businesses and assets.

As of December 31, 2023, White Mountains conducted its business primarily in four areas: municipal bond insurance, property and casualty insurance and reinsurance, capital solutions for asset and wealth management firms and other operations. White Mountains’s municipal bond insurance business is conducted through its subsidiary HG Global Ltd. and its reinsurance subsidiary HG Re Ltd. (“HG Re”) (collectively, “HG Global”). HG Global was established to fund the startup of and provide reinsurance, through HG Re, to Build America Mutual Assurance Company (“BAM”), a mutual municipal bond insurance company (collectively, “HG Global/BAM”). White Mountains’s property and casualty insurance and reinsurance business is conducted through its subsidiary Ark Insurance Holdings Limited and its subsidiaries (collectively, “Ark”) and Outrigger Re Ltd. Segregated Account 2023-1 (“WM Outrigger Re”) (collectively with Ark, “Ark/WM Outrigger”). White Mountains provides capital solutions for asset and wealth management firms through its subsidiary Kudu Investment Management, LLC and its subsidiaries (collectively, “Kudu”).

White Mountains’s other operations consists of the Company and its wholly-owned subsidiary, White Mountains Capital, LLC (“WM Capital”), its other intermediate holding companies, its wholly-owned investment management subsidiary, White Mountains Advisors LLC (“WM Advisors”), investment assets managed by WM Advisors, its interests in MediaAlpha, Inc. (“MediaAlpha”), PassportCard Limited (“PassportCard”) and DavidShield Life Insurance Agency (2000) Ltd. (“DavidShield”) (collectively, “PassportCard/DavidShield”), Elementum Holdings LP (“Elementum”), certain other consolidated and unconsolidated entities and certain other assets (“Other Operations”). As of December 31, 2023, White Mountains’s reportable segments were HG Global/BAM, Ark/WM Outrigger and Kudu with its remaining operating businesses, holding companies and other assets included in Other Operations.

On October 25, 2023, White Mountains announced the launch of White Mountains Partners LLC (“WTM Partners”), which will acquire businesses in non-insurance, non-financial services sectors including essential services, light industrial and specialty consumer. White Mountains expects to deploy up to $500 million of equity capital through WTM Partners over time. WTM Partners is included within Other Operations.

On January 2, 2024, White Mountains acquired a controlling interest in Bamboo Ide8 Insurance Services LLC (“Bamboo MGA”) and its wholly-owned insurance subsidiary, Ide8 Limited (“Bamboo Captive”), through PM Holdings LLC (“Bamboo Holdings”) (collectively with Bamboo MGA and Bamboo Captive, “Bamboo”). Bamboo is a capital-light, tech- and data-enabled insurance distribution business providing homeowners’ insurance and related products to the residential property market in California. Bamboo operates primarily through Bamboo MGA, its full-service managing general agent (“MGA”) business. Bamboo will be consolidated and is expected to be presented as a reportable segment for periods after December 31, 2023. See “Bamboo Transaction” on page 18.