HoldcoTracker marks the reported 13-F equity portfolios of operating and holding companies to last close. Institutional investors with over $100 million in U.S. equities file 13-Fs disclosing those holdings within 45 days of each quarter-end; the lead column below sizes each filer's equity book against the parent company's market cap.
| Company | 13-F as % of Mkt Cap | Days Since Filing | Since Filing | vs S&P since filing |
|---|---|---|---|---|
| Markel Group | 59.9% | 56 | -1% | -4% |
| Loews Corporation | 55% | 42 | -4.7% | -7.7% |
| Berkshire Hathaway | 28.4% | 42 | +3.4% | +0.4% |
| Graham Holdings | 22.1% | 42 | -0.9% | -3.8% |
| Cincinnati Financial | 21.3% | 50 | +2.4% | -0.5% |
| Hingham Institution for Savings | 20.7% | 66 | +0.8% | -2.2% |
| White Mountains Insurance Group | 6.8% | 44 | -13% | -15.9% |
| W.R. Berkley | 4.2% | 42 | +4.3% | +1.3% |
| Alphabet | 2.1% | 49 | -13.2% | -16.2% |
| Nvidia | 1% | 42 | -11.5% | -14.5% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.