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% | 21 | +2.1% | 0% |
| Loews Corporation | 55.9% | 7 | +2.1% | 0% |
| Berkshire Hathaway | 29.3% | 7 | +4.9% | +2.8% |
| Graham Holdings | 21.7% | 7 | -2.1% | -4.2% |
| Hingham Institution for Savings | 20.9% | 31 | +2.2% | +0% |
| Cincinnati Financial | 20.8% | 15 | +3.4% | +1.3% |
| White Mountains Insurance Group | 7.8% | 9 | +3.6% | +1.5% |
| W.R. Berkley | 4.1% | 7 | +5.2% | +3.1% |
| Alphabet | 1.9% | 14 | -20.9% | -23% |
| Nvidia | 0.9% | 7 | -26.5% | -28.6% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.