Mario Gabelli runs GAMCO, an asset manager overseeing $10.41B in disclosed equity holdings (SEC CIK 0000807249). The latest portfolio (2025Q4) discloses 1036 positions across 11 sectors, with the largest positions in MLI, GATX and CR. On a mark-to-market basis the tracked portfolio has returned 21.8% over the past year. OpenStocks tracks 40 consecutive quarterly snapshots for this manager — every position change, new entry, and exit is logged below.
Methodology:TWR tiles chain-link quarterly mark-to-market across consecutive filings (GIPS-compliant) ·actual tiles use a real 13F snapshot marked to today ·backtest tiles re-price the current book to historical prices.
Performance overview
We mark Mario Gabelli (GAMCO)'s disclosed portfolio to current market prices and compare its growth against the S&P 500 (SPY). Mario's portfolio is 21.8% over the last 12 months · 123.0% since 2016Q1.
Portfolio growth vs SPY
Rebased to 100 at 2021Q2 · through 2025Q4
Mario Gabelli
+78.7%
SPY
+69.5%
Alpha
+9.2pp
Portfolio line is the GIPS-compliant time-weighted return chain-linked across the manager's quarterly 13F filings — unaffected by capital flows. Quarters with insufficient held-through coverage are skipped, which can briefly flatten the line.