White Mountains Insurance Ownership & Insider Activity

White Mountains Insurance (WTM) institutional and insider ownership, recent insider transactions and ownership breakdown.

Insiders own 18.9% of shares outstanding. Institutional investors hold 63.4%.

Shares Outstanding

2.387M

Shares Float

2.313M

Insider Shares Owned

450.092K

Insider % Owned

18.9%

Institutional Shares Held

1.514M

Institutional % Held

63.4%

Ownership Breakdown

Net Insider Activity by Month

White Mountains Insurance Insider Transactions (Last 6 Months)

No insider filings in the last 6 months.

Date	Member	Party	Chamber	Action	Amount
Jun 23, 2025	French Hill	R	House	Purchase	$50,001 - $100,000