Company · Ownership research

WHITE MOUNTAINS INSURANCE GROUP LTD WTM

CIK 0000776867 · CUSIP G9618E107

Insider tradingInitial holdingsInstitutional holders

Quarter-end disclosures, not live holdings.

This page lists the top 20 of 353 rows by value; the complete set is available through the API.
Some filings reported values in thousands; those figures were scaled ×1000 to dollars.

Top 20 institutions

Weight means this stock's share of the manager's own portfolio.

By reported value
#ManagerValueManager weightChange vs priorSource

Showing 20 / 353 institutions. The complete set is available through the API.

Coverage & totals by quarter

Reporting institutions
353
Cancelled or null records excluded
Disclosed shares
2,249,179
Not deduplicated across managers
Disclosed value
$4.67B
Not market cap or free float

Reporting institutions by quarter

Counts also change with data coverage and reporting entities; they do not measure net buying. Distinct managers with a live stock row in this CUSIP; totals may include overlapping filings and are not a share of the company.

WHITE MOUNTAINS INSURANCE GROUP LTD · Q4 2025

Explore all 353 reporting institutions.

This page includes 20 of 353 reporting institutions. Sign in to look up the full history beyond 3 years, use advanced screening & filtering, download CSV, and get the complete set through the Akkru API.

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The initial HTML of this page carries its exact data as script#research-data (JSON): values, units, scope, preview limits and SEC sources. Read it directly, no script or API key needed; script#research-access says what needs an account. This page lists 20 of 353 reporting institutions; totals use the complete disclosed data.

Without an account: the last 3 years, with the row caps stated on the page. A free account opens all history on file on these pages and the CSV of what a page shows. Rows beyond the caps and bulk retrieval go through the authenticated API / MCP.

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{"cusip":"G9618E107","quarter":"2025Q4","type":"positions","page_size":100}

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Sources, coverage & how to read this data

Figures are as reported to the SEC and merged with later amendments where Akkru could match them. Preview limits apply to what is listed, not to the totals, which come from the complete reported data. Nothing is zero-filled: a missing quarter or month is shown as missing.