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 | 59.6% | 32 | +2.5% | -0.2% |
| Loews Corporation | 56.2% | 18 | +0.3% | -2.4% |
| Berkshire Hathaway | 28.9% | 18 | +4.9% | +2.2% |
| Graham Holdings | 22.3% | 18 | -1.4% | -4.1% |
| Hingham Institution for Savings | 21.8% | 42 | +2.8% | +0.1% |
| Cincinnati Financial | 20.7% | 26 | +3.9% | +1.2% |
| White Mountains Insurance Group | 7.7% | 20 | +1.4% | -1.3% |
| W.R. Berkley | 4.3% | 18 | +7.2% | +4.5% |
| Alphabet | 2% | 25 | -15.5% | -18.2% |
| Nvidia | 0.9% | 18 | -25.8% | -28.5% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.