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 | 55.3% | 7 | +5.1% | +9.2% |
| Loews Corporation | 54.2% | 84 | -0.7% | +1.1% |
| Berkshire Hathaway | 25.4% | 84 | +4.8% | +6.5% |
| Hingham Institution for Savings | 21.4% | 17 | +6.4% | +10.4% |
| Graham Holdings | 21.3% | 84 | +1.2% | +3% |
| Cincinnati Financial | 18.9% | 3 | +3.5% | +7.5% |
| White Mountains Insurance Group | 7.5% | 86 | +7.7% | +9.5% |
| W.R. Berkley | 3.6% | 84 | +1.6% | +3.3% |
| Alphabet | 2.1% | 91 | -27.5% | -25.8% |
| Nvidia | 0.8% | 84 | -47.5% | -45.8% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.