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 | 58.1% | 77 | +1% | -2.5% |
| Loews Corporation | 54.5% | 63 | -2.2% | -5.7% |
| Berkshire Hathaway | 27.8% | 63 | +5.4% | +1.9% |
| Hingham Institution for Savings | 21.9% | 87 | +5.4% | +1.9% |
| Graham Holdings | 21.7% | 63 | +1.9% | -1.6% |
| Cincinnati Financial | 21.5% | 71 | +6.2% | +2.7% |
| White Mountains Insurance Group | 7.2% | 65 | -2.6% | -6.1% |
| W.R. Berkley | 3.8% | 63 | +4.4% | +0.9% |
| Alphabet | 2% | 70 | -13.2% | -16.7% |
| Nvidia | 0.9% | 63 | -24.3% | -27.7% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.