White Mountains details $393.6M in 13F holdings

Q: What does White Mountains Insurance Group (WTM) report in this Form 13F?

White Mountains Insurance Group reports a Form 13F Holdings Report listing 2 reportable positions with a total reported value of $393,601,043. All of the manager’s reportable holdings are included in this filing.

Q: What is the total reported value of WTM’s Form 13F holdings?

The Form 13F Summary Page shows a total reported value of $393,601,043 for White Mountains Insurance Group’s reportable holdings, rounded to the nearest dollar, across 2 positions in the information table.

Q: Are there any other included managers in WTM’s Form 13F filing?

No. The Form 13F Summary Page states the Number of Other Included Managers is 0 and explicitly lists NONE under other included managers, meaning only White Mountains Insurance Group is reporting.

Q: Who signed the Form 13F for White Mountains Insurance Group (WTM)?

The report is signed by Michaela J. Hildreth, Managing Director and Chief Accounting Officer, with a listed phone number of 603-640-2200 and a signing location of Boston, Massachusetts.

Q: What type of 13F report did White Mountains Insurance Group (WTM) file?

White Mountains Insurance Group filed a 13F HOLDINGS REPORT, indicating that all of the reporting manager’s Form 13F-reportable holdings are disclosed in this single report, rather than via notices or combination reports.

White Mountains Insurance Group Ltd., an institutional investment manager, filed a Form 13F Holdings Report indicating that all of its reportable equity holdings are included in this submission.

Filing Impact

(Neutral)

Filing Sentiment

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Sentiment and the balance of points

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Form Type

13F-HR

Rhea-AI Filing Summary

White Mountains Insurance Group Ltd., an institutional investment manager, filed a Form 13F Holdings Report indicating that all of its reportable equity holdings are included in this submission. The report covers 2 line-item positions with an aggregate reported value of $393,601,043. No other investment managers are included in this filing, and the report is signed by Managing Director and Chief Accounting Officer Michaela J. Hildreth.

Key Figures

Form 13F Information Table Value Total: $393,601,043 Form 13F Information Table Entry Total: 2 Number of Other Included Managers: 0

3 metrics

Form 13F Information Table Value Total $393,601,043 Aggregate value of all reportable holdings, rounded to nearest dollar

Form 13F Information Table Entry Total 2 Number of line-item holdings reported in the 13F information table

Number of Other Included Managers 0 No other institutional investment managers included in this report

Key Terms

Form 13F, Institutional Investment Manager, 13F HOLDINGS REPORT

3 terms

Form 13F regulatory

"The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete. The reader should not assume that the information is accurate and complete. -------------------------------------------------------------------------------- | FORM 13F FORM 13F COVER PAGE"

A Form 13F is a quarterly filing that large investment managers must submit to disclose their holdings in publicly traded stocks and certain other securities. It acts like a peek into the portfolios of big investors, helping other market participants see what large players are buying or selling and offering clues about investment trends, crowded trades, and potential market impact.

Institutional Investment Manager regulatory

"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"

13F HOLDINGS REPORT regulatory

"Report Type (Check only one.) X | 13F HOLDINGS REPORT. (Check here if all holdings of this reporting manager are reported in this report.)"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does White Mountains Insurance Group (WTM) report in this Form 13F?

White Mountains Insurance Group reports a Form 13F Holdings Report listing 2 reportable positions with a total reported value of $393,601,043. All of the manager’s reportable holdings are included in this filing.

How many securities are disclosed in WTM’s latest Form 13F-HR?

The Form 13F-HR for White Mountains Insurance Group discloses 2 information table entries. These represent the manager’s reportable equity holdings under SEC rules for this reporting period.

What is the total reported value of WTM’s Form 13F holdings?

The Form 13F Summary Page shows a total reported value of $393,601,043 for White Mountains Insurance Group’s reportable holdings, rounded to the nearest dollar, across 2 positions in the information table.

Are there any other included managers in WTM’s Form 13F filing?

No. The Form 13F Summary Page states the Number of Other Included Managers is 0 and explicitly lists NONE under other included managers, meaning only White Mountains Insurance Group is reporting.

Who signed the Form 13F for White Mountains Insurance Group (WTM)?

The report is signed by Michaela J. Hildreth, Managing Director and Chief Accounting Officer, with a listed phone number of 603-640-2200 and a signing location of Boston, Massachusetts.

What type of 13F report did White Mountains Insurance Group (WTM) file?

White Mountains Insurance Group filed a 13F HOLDINGS REPORT, indicating that all of the reporting manager’s Form 13F-reportable holdings are disclosed in this single report, rather than via notices or combination reports.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/12/2026 - 04:22 PM Accepted by SEC EDGAR 08/12/2026 - 04:21 PM

The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F COVER PAGE

OMB APPROVAL

OMB Number:			3235-0006
Estimated average burden
hours per response:			23.8

Report for the Calendar Year or Quarter Ended:

06-30-2026

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 INSURANCE GROUP LTD
Address:	23 South Main Street
	Suite 3B
	Hanover, NH 03755
Form 13F File Number:	028-01681
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 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:	Michaela J. Hildreth
Title:	Managing Director and Chief Accounting Officer
Phone:	603-640-2200
Signature, Place, and Date of Signing:
/s/ Michaela J. Hildreth		Boston, MA	08-12-2026
[Signature]		[City, State]	[Date]

Report Type (Check only one.):
X	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).)
	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).)

Form 13F Summary Page
	Report Summary:
	Number of Other Included Managers:	0
	Form 13F Information Table Entry Total:	2
	Form 13F Information Table Value Total:	393,601,043
		(round to nearest dollar)

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.
[If there are no entries in this list, state "NONE" and omit the column headings and list entries.]
NONE

Source: View Original Filing on SEC EDGAR