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 | 60.1% | 68 | -0.4% | -4.9% |
| Loews Corporation | 54.4% | 54 | -4.5% | -9% |
| Berkshire Hathaway | 28.1% | 54 | +2.5% | -2% |
| Graham Holdings | 22% | 54 | -0.5% | -5% |
| Hingham Institution for Savings | 21.7% | 78 | +1.9% | -2.6% |
| Cincinnati Financial | 21.6% | 62 | +4.3% | -0.2% |
| White Mountains Insurance Group | 7% | 56 | -11.3% | -15.7% |
| W.R. Berkley | 4.2% | 54 | +7.5% | +3% |
| Alphabet | 2.3% | 61 | +0.1% | -4.4% |
| Nvidia | 1% | 54 | -10.5% | -14.9% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.