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 | 54.8% | 56 | +8.1% | -3.8% |
| Loews Corporation | 53.1% | 42 | +2.3% | -9.5% |
| Berkshire Hathaway | 26.7% | 42 | +6.9% | -5% |
| Graham Holdings | 20.8% | 42 | +6.8% | -5.1% |
| Cincinnati Financial | 19.7% | 46 | +8.9% | -3% |
| Hingham Institution for Savings | 13.2% | 72 | +9.3% | -2.6% |
| White Mountains Insurance Group | 7.3% | 45 | +15.8% | +3.9% |
| W.R. Berkley | 3.1% | 42 | +4.5% | -7.4% |
| Nvidia | 0.9% | 42 | +124.3% | +112.4% |
| Alphabet | 0.1% | 49 | +6.5% | -5.4% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.