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 | 59.9% | 25 | +3.7% | +1.4% |
| Loews Corporation | 55.7% | 11 | +2.4% | +0.1% |
| Berkshire Hathaway | 29.1% | 11 | +5.8% | +3.5% |
| Graham Holdings | 21.6% | 11 | -0.6% | -2.9% |
| Hingham Institution for Savings | 21% | 35 | +4.3% | +2.1% |
| Cincinnati Financial | 20.5% | 19 | +4% | +1.7% |
| White Mountains Insurance Group | 7.6% | 13 | +2% | -0.3% |
| W.R. Berkley | 4.1% | 11 | +4.9% | +2.6% |
| Alphabet | 1.9% | 18 | -20.3% | -22.6% |
| Nvidia | 0.9% | 11 | -28.5% | -30.8% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.