# WHITE MTNS INS GROUP LTD (WTM) — Institutional Ownership

Source: SEC EDGAR 13F filings, congressional STOCK Act disclosures, SEC Form 4 insider transactions.
CUSIP: G9618E107
Page URL: https://superinvestorclub.com/stock/WTM
Last updated: 2026-08-29T13:49:25.944Z

## Summary

As of the most recent 13F filing period, WHITE MTNS INS GROUP LTD (WTM) is held by 1 tracked superinvestors with an aggregate position value of $35.5M representing 017104 shares.

## Top institutional holders (1)

| Rank | Manager | Fund | Shares | Value | % of Portfolio | Period |
|------|---------|------|--------|-------|----------------|--------|
| 1 | [Longleaf Partners](https://superinvestorclub.com/manager/15) | Southeastern Asset Management | 17104 | $35.5M | 1.85% | 2026-06-30 |

## Ownership history (quarter-over-quarter)

- 2024-03-31: 1 holders, $44.3M aggregate, 024708 shares
- 2024-06-30: 2 holders, $40.3M aggregate, 021423756 shares
- 2024-09-30: 1 holders, $35.2M aggregate, 020738 shares
- 2024-12-31: 1 holders, $37.4M aggregate, 019244 shares
- 2025-03-31: 1 holders, $35.6M aggregate, 018484 shares
- 2025-06-30: 1 holders, $37.9M aggregate, 021094 shares
- 2025-09-30: 1 holders, $52.9M aggregate, 031652 shares
- 2025-12-31: 1 holders, $65.8M aggregate, 031652 shares
- 2026-03-31: 2 holders, $42.4M aggregate, 018864414 shares
- 2026-06-30: 1 holders, $35.5M aggregate, 017104 shares

## Recent congressional trades (5)

- 2025-08-21: Michael McCaul (Republican-TX) sale $1,001 - $15,000
- 2025-08-20: Michael McCaul (Republican-TX) purchase $15,001 - $50,000
- 2025-06-23: James French Hill (-AR) purchase $50,001 - $100,000
- 2025-06-23: French Hill (Republican-AR) purchase $50,001 - $100,000
- 2025-01-23: Michael McCaul (Republican-TX) purchase $15,001 - $50,000

## Recent insider transactions (0)


## Citation

When citing, use: "WHITE MTNS INS GROUP LTD (WTM) institutional ownership data via Superinvestor (https://superinvestorclub.com/stock/WTM), aggregating SEC 13F, Form 4, and congressional disclosures."