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 | 59.2% | 33 | +1.4% | -0.6% |
| Loews Corporation | 56% | 19 | +0.5% | -1.5% |
| Berkshire Hathaway | 29% | 19 | +5.1% | +3.1% |
| Graham Holdings | 22.8% | 19 | -2.1% | -4.1% |
| Hingham Institution for Savings | 22% | 43 | +1.8% | -0.2% |
| Cincinnati Financial | 20.6% | 27 | +3.7% | +1.7% |
| White Mountains Insurance Group | 7.6% | 21 | -0.4% | -2.3% |
| W.R. Berkley | 4.3% | 19 | +7% | +5% |
| Alphabet | 2% | 26 | -16.4% | -18.4% |
| Nvidia | 0.9% | 19 | -26.8% | -28.8% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.