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 | 58.8% | 15 | +3.5% | -0.5% |
| Loews Corporation | 56.4% | 1 | +5.1% | +1% |
| Berkshire Hathaway | 28.9% | 1 | +5.1% | +1% |
| Graham Holdings | 21.5% | 1 | +0% | -4% |
| Cincinnati Financial | 20.5% | 9 | +4.8% | +0.7% |
| Hingham Institution for Savings | 20.3% | 25 | +2.9% | -1.1% |
| White Mountains Insurance Group | 7.8% | 3 | +4.4% | +0.4% |
| W.R. Berkley | 4.1% | 1 | +6.4% | +2.4% |
| Alphabet | 1.9% | 8 | -17.4% | -21.4% |
| Nvidia | 0.9% | 1 | -19.8% | -23.8% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.