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White Mountains Insurance Group (WTM) 10K Form and Latest SEC Filings 2026

White Mountains Insurance Group logo
$2,138.76 -6.05 (-0.28%)
Closing price 03:59 PM Eastern
Extended Trading
$2,137.92 -0.84 (-0.04%)
As of 04:10 PM Eastern
Extended trading is trading that happens on electronic markets outside of regular trading hours. This is a fair market value extended hours price provided by Massive. Learn more.

Latest White Mountains Insurance Group SEC Filings & Recent Activity

White Mountains Insurance Group (NYSE:WTM) has submitted 391+ documents to the U.S. Securities and Exchange Commission (SEC) since 2017. For investors, these filings are the primary source of verified financial data — covering everything from annual revenue and debt levels in the 10-K, to material business events in 8-K current reports, to insider buying and selling activity in Form 4 disclosures. Key figures from these filings, including revenue, earnings, and cash flow, are summarized in White Mountains Insurance Group's financial statements. The most recent filing was a Form 8-K submitted on May 21, 2026.

Form 4
WHITE MOUNTAINS INSURANCE GROUP LTD Reports Ownership Change on Mar. 20, 2026

Form 4 filings disclose changes in stock ownership by company insiders, including purchases, sales, grants, and option exercises.

View insider ownership

8-K
White Mountains Insurance Group Files Current Report on May. 21, 2026

An 8-K is filed when a material corporate event occurs, such as an acquisition, leadership change, or financial update.

View filing

10-Q
White Mountains Insurance Group Files Quarterly Report on May. 6, 2026

The 10-Q contains White Mountains Insurance Group's unaudited quarterly financial statements, revenue, earnings updates, and cash flow changes between annual reports.

View earnings history

White Mountains Insurance Group SEC Filing History

Browse White Mountains Insurance Group's complete SEC filing history using the filters below. Filter by form type - 10-K, 10-Q, 8-K, Form 4, and more - or set a custom date range to find a filing.

DateFilerForm TypeView
05/21/2026 3:21 PM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
05/15/2026 8:02 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
05/07/2026 10:56 AM
Neuberger Berman Group LLC (1465109) Filed by
White Mountains Insurance Group (776867) Subject
Form SCHEDULE 13G/A
05/06/2026 7:31 AM
White Mountains Insurance Group (776867) Filer
Form 10-Q
General form for quarterly reports under Section 13 or 15(d)  
05/06/2026 7:20 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
05/01/2026 4:30 PM
MediaAlpha, Inc. (1818383) Subject
White Mountains Insurance Group (776867) Filed by
Form SCHEDULE 13D/A
04/30/2026 1:28 PM
VANGUARD CAPITAL MANAGEMENT LLC (2100119) Filed by
White Mountains Insurance Group (776867) Subject
Form SCHEDULE 13G
04/01/2026 3:21 PM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
03/27/2026 1:17 PM
VANGUARD GROUP INC (102909) Filed by
White Mountains Insurance Group (776867) Subject
Form SCHEDULE 13G/A
03/20/2026 1:51 PM
SEELIG ROBERT LAWRENCE (1188198) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
03/05/2026 9:21 AM
Tanner David Allen (1318960) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
02/27/2026 10:18 AM
Harrison Giles E (2019288) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
02/27/2026 10:19 AM
Caffrey Liam P (1915424) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
02/27/2026 10:17 AM
SEELIG ROBERT LAWRENCE (1188198) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
02/27/2026 10:17 AM
Papamichael Michael A (2090784) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
02/27/2026 10:18 AM
Hildreth Michaela (1863001) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
02/27/2026 8:21 AM
White Mountains Insurance Group (776867) Filer
Form 10-K
Annual report pursuant to Section 13 or 15(d)  
02/26/2026 4:19 PM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
02/12/2026 4:26 PM
White Mountains Insurance Group (776867) Filer
Form 13F-HR
Initial Quarterly Form 13F Holdings report filed by institutional managers
02/12/2026 9:38 AM
MORGAN STANLEY (895421) Filed by
White Mountains Insurance Group (776867) Subject
Form SCHEDULE 13G/A
02/06/2026 7:21 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
01/07/2026 7:02 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
01/05/2026 8:09 AM
Hildreth Michaela (1863001) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
01/02/2026 8:28 PM
Papamichael Michael A (2090784) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
01/02/2026 8:26 PM
Papamichael Michael A (2090784) Reporting
White Mountains Insurance Group (776867) Issuer
Form 3
Initial statement of beneficial ownership of securities  
01/02/2026 5:02 PM
Caffrey Liam P (1915424) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
01/02/2026 5:04 PM
SEELIG ROBERT LAWRENCE (1188198) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
12/29/2025 5:04 AM
White Mountains Insurance Group (776867) Subject
Form SC TO-I/A
12/23/2025 12:55 PM
Hildreth Michaela (1863001) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
12/22/2025 3:51 PM
CAMPBELL REID TARLTON (1378156) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4/A
12/22/2025 9:13 AM
Rountree George Manning (1457475) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
12/22/2025 9:14 AM
CAMPBELL REID TARLTON (1378156) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
12/22/2025 7:37 AM
White Mountains Insurance Group (776867) Subject
Form SC TO-I/A
12/16/2025 7:41 PM
Gelston Philip A (1733327) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
12/08/2025 7:10 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
11/26/2025 9:25 AM
CAMPBELL REID TARLTON (1378156) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
11/21/2025 5:03 AM
White Mountains Insurance Group (776867) Subject
Form SC TO-I
11/13/2025 7:28 AM
White Mountains Insurance Group (776867) Filer
Form 13F-HR
Initial Quarterly Form 13F Holdings report filed by institutional managers
11/10/2025 2:30 PM
Tanner David Allen (1318960) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
11/07/2025 10:48 AM
MORGAN STANLEY (895421) Filed by
White Mountains Insurance Group (776867) Subject
Form SCHEDULE 13G/A
11/06/2025 8:07 AM
White Mountains Insurance Group (776867) Filer
Form 10-Q
General form for quarterly reports under Section 13 or 15(d)  
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11/06/2025 7:18 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
09/03/2025 7:06 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
09/02/2025 7:19 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
08/08/2025 3:22 PM
MediaAlpha, Inc. (1818383) Subject
White Mountains Insurance Group (776867) Filed by
Form SCHEDULE 13D/A
08/07/2025 7:28 AM
White Mountains Insurance Group (776867) Filer
Form 10-Q
General form for quarterly reports under Section 13 or 15(d)  
08/07/2025 7:03 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
07/18/2025 8:25 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
07/16/2025 3:29 PM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
07/07/2025 7:58 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
06/06/2025 6:59 AM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
05/27/2025 8:59 AM
SHANK SUZANNE F. (1713197) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:09 PM
CHOKSI MARY C (1205706) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:10 PM
Dillon Margaret (1787371) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:10 PM
Gelston Philip A (1733327) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:10 PM
Hicks Weston M (1186549) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:11 PM
Tanner David Allen (1318960) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:12 PM
White Mountains Insurance Group (776867) Issuer
Yi Steven (1829946) Reporting
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:08 PM
CAMPBELL REID TARLTON (1378156) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/23/2025 6:09 PM
Carlson Peter M (1379320) Reporting
White Mountains Insurance Group (776867) Issuer
Form 4
Statement of changes in beneficial ownership of securities  
05/22/2025 3:18 PM
White Mountains Insurance Group (776867) Filer
Form 8-K
Current report pursuant to Section 13 or 15(d)  
(Data available from 1/1/2016 forward)

White Mountains Insurance Group SEC Filings - Frequently Asked Questions

White Mountains Insurance Group (WTM) has submitted 391+ filings to the SEC since 2017. You can browse the complete history or filter by form type using the tools above.

White Mountains Insurance Group's fiscal year ends on December 31. The company typically files its 10-K annual report by the end of February, covering the prior fiscal year's financial results. Key financial data from these reports is available on White Mountains Insurance Group's financial statements page.

The most recent filing was a Form 8-K submitted on May 21, 2026. This was a current report on a material business event.

SEC Filing Types: 10-K, 10-Q, 8-K and More

SEC filings are legally required disclosures that public companies submit to the U.S. Securities and Exchange Commission. Unlike press releases or earnings call transcripts, these documents are filed under legal obligation — meaning the financial data they contain is audited, standardized, and subject to penalties if materially false. For investors, that makes SEC filings the most reliable primary source available for evaluating a company's true financial position.

Yes. All SEC filings are publicly available through the SEC's EDGAR database and on financial research platforms like MarketBeat. Companies are required by law to make these disclosures accessible to all investors — meaning retail investors have access to the same source documents as institutional analysts.

A 10-K is an annual report containing audited financial statements and a full review of the company's business — it is the most comprehensive filing a company makes each year. A 10-Q is a shorter, unaudited quarterly update filed three times per year between annual reports. Investors typically use the 10-K for deep fundamental analysis and the 10-Q to track whether the company is on pace with its guidance mid-year.

The most important filing for fundamental investors. Filed once per year, the 10-K contains audited financial statements, revenue and earnings trends, debt obligations, risk factors, and management's own assessment of the business. Reading the risk factors section and comparing year-over-year financials can reveal issues that don't show up in analyst summaries.

An unaudited financial update filed three times per year (the 10-K covers Q4). Investors use 10-Qs to track whether guidance is on pace, monitor changes in cash flow or inventory, and catch any mid-year shifts in business conditions before they become headline news.

Filed within four business days of a material event — earnings releases, merger announcements, executive departures, or major asset sales. Because 8-Ks are filed before media coverage catches up, they are often the fastest way to get unfiltered information directly from the company on market-moving events.

Filed within two business days whenever an executive or director buys or sells company stock. Insider purchases — especially large or clustered buys — are often interpreted as a signal of management confidence. Insider selling is more ambiguous but worth monitoring for patterns, particularly around lock-up expirations or ahead of major announcements.


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This page (NYSE:WTM) was last updated on 5/21/2026 by MarketBeat.com Staff.
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