{
 "company": "White Mountains Insurance Group",
 "ticker": "WTM",
 "page": "https://www.moatshark.com/s/wtm",
 "note": "Source: SEC filings via moatshark. Values and changes are estimates; not investment advice.",
 "holders": [
  {
   "manager": "Southeastern Asset Management",
   "moatshark_slug": "southeastern-asset-management",
   "period": "2026-06-30",
   "portfolio_pct": 1.85,
   "value_usd": 35463263,
   "change": "REDUCE",
   "share_change_pct": -9.3,
   "quarters_held": 19
  },
  {
   "manager": "Horizon Kinetics",
   "moatshark_slug": "horizon-kinetics",
   "period": "2026-06-30",
   "portfolio_pct": 0.29,
   "value_usd": 25307802,
   "change": "REDUCE",
   "share_change_pct": -6.9,
   "quarters_held": 9
  }
 ]
}