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 | 53.7% | 57 | +8% | -3.8% |
| Loews Corporation | 53.6% | 43 | +5.4% | -6.5% |
| Berkshire Hathaway | 26.4% | 43 | +7.9% | -4% |
| Graham Holdings | 20.6% | 43 | +7.9% | -3.9% |
| Cincinnati Financial | 18.9% | 47 | +8.6% | -3.2% |
| Hingham Institution for Savings | 13.1% | 73 | +10.3% | -1.5% |
| White Mountains Insurance Group | 7.3% | 46 | +20.4% | +8.5% |
| W.R. Berkley | 2.9% | 43 | +2% | -9.9% |
| Nvidia | 0.8% | 43 | +116.3% | +104.4% |
| Alphabet | 0.1% | 50 | +8.5% | -3.4% |
Data updates nightly after U.S. market close. 13-F positions reflect last quarterly filing; prices marked to most recent close.