{
 "company": "Martin Marietta Materials Ord",
 "ticker": "MLM",
 "page": "https://www.moatshark.com/s/mlm",
 "note": "Source: SEC filings via moatshark. Values and changes are estimates; not investment advice.",
 "holders": [
  {
   "manager": "Gardner Russo & Quinn",
   "moatshark_slug": "gardner-russo-quinn",
   "period": "2026-06-30",
   "portfolio_pct": 4.56,
   "value_usd": 406784959,
   "change": "REDUCE",
   "share_change_pct": -1.4,
   "quarters_held": 53
  },
  {
   "manager": "Weitz Investment Management",
   "moatshark_slug": "weitz-investment-management",
   "period": "2026-06-30",
   "portfolio_pct": 1.89,
   "value_usd": 27318279,
   "change": "ADD",
   "share_change_pct": 19.1,
   "quarters_held": 36
  },
  {
   "manager": "TCI Fund Management",
   "moatshark_slug": "tci-fund-management",
   "period": "2026-06-30",
   "portfolio_pct": 1.44,
   "value_usd": 758423360,
   "change": "NEW",
   "share_change_pct": null,
   "quarters_held": 1
  }
 ]
}