13F-HR 1 a2170361z13f-hr.txt 13F-HR UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 13F FORM 13F COVER PAGE Report for the Calendar Year or Quarter Ended: March 31, 2006 ----------------------- Check Here if Amendment / /; Amendment Number: --------- This Amendment (Check only one.): / / is a restatement. / / adds new holdings entries. Institutional Investment Manager Filing this Report: Name: White Mountains Advisors LLC ------------------------------- Address: 370 Church Street ------------------------------- Guilford, CT 06437 ------------------------------- Form 13F File Number: 28-00470 --------------------- The institutional investment manager filing this report and the person by whom it is signed hereby represent that the person signing the report is authorized to submit it, that all information contained herein is true, correct and complete, and that it is understood that all required items, statements, schedules, lists, and tables, are considered integral parts of this form. Person Signing this Report on Behalf of Reporting Manager: Name: Mark J. Plourde ------------------------------- Title: Chief Financial Officer ------------------------------- Phone: (203) 458-5805 ------------------------------- Signature, Place, and Date of Signing: /s/ Mark J. Plourde Guilford, Connecticut May 12, 2006 ------------------------------- --------------------- ------------- [Signature] [City, State] [Date] 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 reporting manager(s).) /X/ 13F COMBINATION REPORT. (Check here if a portion of the holdings for this reporting manager are reported in this report and a portion are reported by other reporting manager(s).) List of Other Managers Reporting for this Manager: Form 13F File Number Name 28-04685 Prospector Partners, LLC --------------- ------------------------------------ 28-05231 Pillar Point Equity Management, LLC --------------- ------------------------------------ 28-03130 Fenimore Asset Management, Inc. --------------- ------------------------------------ 28-04903 Gartmore SA Capital Trust --------------- ------------------------------------ 28-00058 Pioneer Investment Management, Inc. --------------- ------------------------------------ FORM 13F SUMMARY PAGE Report Summary: Number of Other Included Managers: 1 -------------------- Form 13F Information Table Entry Total: 1 -------------------- Form 13F Information Table Value Total: 102,840 -------------------- (thousands) 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 to which this report is filed, other than the manager filing this report. No. Form 13F File Number Name 1. 28-01681 White Mountains Insurance Group, Ltd. ------ ----------------- ------------------------------------- WHITE MOUNTAINS ADVISORS LLC WHITE MOUNTAINS ADVISORS LLC FORM 13F INFORMATION TABLE - MARCH 31, 2006
----------------------------------------------------------------------------------------------------------------------------------- Amount and Title Market Type of Investment Other Voting Authority (Shares) Name of Issuer of Class CUSIP Value Security Discretion Managers Sole Shared None ----------------------------------------------------------------------------------------------------------------------------------- 1 MONTPELIER RE HOLDINGS LTD SHS G62185106 $102,840 6,309,189 SH DEFINED 01 6,309,189
01 White Mountains Insurance Group, Ltd.