White Mountains Insurance Group, Ltd.
CIK 776867 · View on SEC EDGAR ↗
First SEC filing: March 10, 2004 · Latest: May 1, 2026
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- Biography Career background and public profile, where available.
- Institution The 13F filer entity this person is associated with.
- Insider at Companies where this person is a reporting insider.
- Insider transactions Every share this person bought or sold, from Form 4 filings.
- Derivatives Options and other derivative holdings reported by this person.
- Initial holdings The stakes this person held when they first started reporting.
White Mountains Insurance Group is a diversified insurance and related financial services holding company based in Hamilton, Bermuda. Redomiciled from Delaware, United States, on October 25, 1999, the company conducts most of its business through its insurance subsidiaries and other affiliates.
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White Mountains Insurance Group is a diversified insurance and related financial services holding company based in Hamilton, Bermuda. Redomiciled from Delaware, United States, on October 25, 1999, the company conducts most of its business through its insurance subsidiaries and other affiliates.
The company owned the automobile insurer Esurance before selling it to Allstate for $1 billion.
Heritage
White Mountains Insurance Group began in the early 1980s by John J. Byrne, the man recruited by American Express to turn around troubled property and casualty insurer Fireman's Fund. When Byrne took Fireman's Fund public in 1985, it was the largest IPO in American history, and the insurer was sold to Allianz six years later. Upon completion of the Fireman's Fund sale in 1991, the remaining holding company and residual assets formed the starting point for the future White Mountains.
In December 2020, the company reported book value per share of $1,000.
Leadership
White Mountains Insurance's current director is CEO George Manning Rountree.
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Institution
Insider at
Insider transactions
Price change vs current quote, split-adjusted for corporate actions since the filing — not benchmarked, not annualized, not size-weighted
| Date | Ticker | Code | Shares | Price | Value | Owned after | Δ own | A/D | vs now |
|---|---|---|---|---|---|---|---|---|---|
| Oct. 30, 2020 | MAX | S | 3,609,894 | $19.00 | $68,587,986 | 20,532,202 Indirect | -14.95% | Disposed | -31.7% (price as of 2026-08-21) |
| March 15, 2007 | WTM | S | 645,262 | $25.85 | $16,680,023 | 71,754,738 Indirect | -0.89% | Disposed | 8092.3% (price as of 2026-08-21) |
| Nov. 14, 2006 | WTM | S | 27,600,000 | $23.56 | $650,256,000 | 72,400,000 Indirect | -27.60% | Disposed | 8888.5% (price as of 2026-08-21) |
| Sept. 27, 2006 | WTM | S | 5,370,150 | $19.40 | $104,180,910 | 929,850 Indirect | -85.24% | Disposed | 10816.0% (price as of 2026-08-21) |
| March 12, 2004 | WTM | S | 4,500,000 | $34.50 | $155,250,000 | 3,600,000 Indirect | -55.56% | Disposed | 6038.3% (price as of 2026-08-21) |
| March 8, 2004 | WTM | P | 2,390,786 | $22.63 | $54,103,487 | 7,172,358 Indirect | +50.00% | Acquired | 9257.9% (price as of 2026-08-21) |
P = Open-market purchase · S = Sale · A = Grant/award · M = Option exercise · G = Gift · F = Tax withholding
Insider transactions are not a recommendation; sales are often driven by liquidity or tax reasons.
Derivative holdings (Form 4 Table II)
Options, RSUs and convertible securities reported on Form 4 Table II.
| Date | Ticker | Security | Underlying | Exercise price | Expiration | Shares | A/D |
|---|---|---|---|---|---|---|---|
| June 20, 2013 | WTM | Warrants to Purchase Common Stock | Common Stock (9,487,872) | $11.49 | July 29, 2014 | 9,487,872 | Disposed |
| March 8, 2004 | WTM | Warrant Shares | Common Shares (2,390,786) | — | Jan. 3, 2012 | 2,390,786 | Acquired |
Exercise/conversion price is blank when not applicable (e.g. RSUs).
Initial ownership (Form 3) 6 holdings
Securities held when first becoming an insider, per SEC Form 3.
| Date | Ticker | Security | Shares | Ownership |
|---|---|---|---|---|
| Oct. 28, 2020 | MAX | CLASS A COMMON STOCK | 24,142,096 | Indirect |
| Jan. 22, 2010 | WTM | Common Stock | 17,400,000 | Indirect |
| Jan. 22, 2010 | WTM | Warrants to Purchase Common Stock→ Common Stock (9,487,872) | 9,487,872 | Indirect |
| Jan. 21, 2010 | WTM | Common Stock | 17,400,000 | Indirect |
| Jan. 21, 2010 | WTM | Warrants to Purchase Common Stock→ Common Stock (9,487,872) | 9,487,872 | Indirect |
| Nov. 6, 2006 | WTM | Common Shares | 100,000,000 | Indirect |