白山保险集团 2026年季度报告

Washington, D.C. 20549FORM 13F FORM 13F COVER PAGE 12-31-2025 Report for the Calendar Year or Quarter Ended: Amendment Number: Check here if Amendment This Amendment (Check only one.): Institutional Investment Manager Filing this Report: WHITE MOUNTAINS INSURANCE GROUP LTD23 SOUTH MAIN STREETSUITE 3B Name: Form 13F File Number:CRD Number (if applicable):SEC File Number (if applicable): The institutional investment manager filing this report and the person by whom it is signed hereby represent that theperson signing the report is authorized to submit it, that all information contained herein is true, correct andcomplete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered Person Signing this Report on Behalf of Reporting Manager: Michaela J. HildrethManaging Director and Chief Accounting Officer603-640-2200 Name:Title:Phone: Signature, Place, and Date of Signing: Boston,MA[City, State] 02-12-2026[Date] /s/ Michaela J. Hildreth Report Type (Check only one.): 13F HOLDINGS REPORT. (Check here if all holdings of this reporting manager are reported in this report.) 13F NOTICE. (Check here if no holdings reported are in this report, and all holdings are reported by other reportingmanager(s).) Report Summary: Number of Other IncludedManagers: List of Other Included Managers: Provide a numbered list of the name(s) and Form 13F file number(s) of all institutional investment managers with respect towhich this report is filed, other than the manager filing this report.