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% | 20 | +2.7% | -0.3% |
| Loews Corporation | 56.1% | 6 | +2.8% | -0.2% |
| Berkshire Hathaway | 29.4% | 6 | +6.1% | +3.1% |
| Graham Holdings | 21.5% | 6 | -1.3% | -4.3% |
| Cincinnati Financial | 20.9% | 14 | +4.2% | +1.2% |
| Hingham Institution for Savings | 20.7% | 30 | +2.7% | -0.3% |
| White Mountains Insurance Group | 7.9% | 8 | +5.5% | +2.5% |
| W.R. Berkley | 4.1% | 6 | +5.2% | +2.2% |
| Alphabet | 1.9% | 13 | -17.7% | -20.7% |
| Nvidia | 0.9% | 6 | -25.1% | -28.1% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.