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% | 28 | +3.1% | -0.4% |
| Loews Corporation | 55.9% | 14 | +1.2% | -2.3% |
| Berkshire Hathaway | 29% | 14 | +5.4% | +1.9% |
| Graham Holdings | 22.1% | 14 | -0.5% | -4.1% |
| Hingham Institution for Savings | 21.4% | 38 | +3.7% | +0.2% |
| Cincinnati Financial | 20.5% | 22 | +4.5% | +0.9% |
| White Mountains Insurance Group | 7.6% | 16 | +2.4% | -1.1% |
| W.R. Berkley | 4.2% | 14 | +7.3% | +3.7% |
| Alphabet | 2% | 21 | -16.2% | -19.8% |
| Nvidia | 0.9% | 14 | -24.5% | -28.1% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.