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 | 59.4% | 43 | +1% | -1.3% |
| Loews Corporation | 54.8% | 29 | -1.6% | -3.9% |
| Berkshire Hathaway | 28.8% | 29 | +5.9% | +3.6% |
| Graham Holdings | 22.2% | 29 | -1% | -3.3% |
| Cincinnati Financial | 20.6% | 37 | +3.5% | +1.1% |
| Hingham Institution for Savings | 19.8% | 53 | +1.3% | -1% |
| White Mountains Insurance Group | 7.5% | 31 | -3.2% | -5.5% |
| W.R. Berkley | 4.1% | 29 | +6.8% | +4.5% |
| Alphabet | 2.1% | 36 | -11.5% | -13.9% |
| Nvidia | 1% | 29 | -19.1% | -21.5% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.