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 | 60.5% | 57 | -0.4% | -3.9% |
| Loews Corporation | 55% | 43 | -5% | -8.5% |
| Berkshire Hathaway | 28.5% | 43 | +3.9% | +0.4% |
| Graham Holdings | 22% | 43 | -0.8% | -4.2% |
| Cincinnati Financial | 21.5% | 51 | +3.3% | -0.1% |
| Hingham Institution for Savings | 20.6% | 67 | +1.1% | -2.4% |
| White Mountains Insurance Group | 6.8% | 45 | -13.6% | -17% |
| W.R. Berkley | 4.2% | 43 | +4.5% | +1% |
| Alphabet | 2.1% | 50 | -12.9% | -16.3% |
| Nvidia | 1% | 43 | -13% | -16.5% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.