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% | 5 | +4.4% | +1% |
| Loews Corporation | 57.3% | 82 | +15.3% | -2.4% |
| Berkshire Hathaway | 27.2% | 82 | +15.3% | -2.4% |
| Graham Holdings | 21.5% | 82 | +14.2% | -3.4% |
| Hingham Institution for Savings | 21.3% | 15 | +6.2% | +2.8% |
| Cincinnati Financial | 19.9% | 86 | +11.5% | -6.1% |
| White Mountains Insurance Group | 7.6% | 85 | +26.3% | +8.6% |
| W.R. Berkley | 3% | 82 | +4.1% | -13.6% |
| Nvidia | 0.6% | 82 | +76.3% | +58.7% |
| Alphabet | 0.1% | 89 | +8.8% | -8.9% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.