Founded by Mario Gabelli back in 1976, GAMCO Investors, which now manages some $40 billion, is a traditional value firm. The asset manager is seeking companies valued in public markets at far less than their potential worth to a third-party buyer. Valuation analysis is based on a firm's private market value, with an emphasis on catalysts, primarily mergers and acquisitions.
In the December 31 issue of Value Investor Insight, three of GAMCO's senior portfolio managers, Kevin Dreyer, Jeff Jonas and Christopher Marangi revealed how they go about calculating a firm's private market value and what sort of margin of safety they're looking for in a potential investment. Below is a brief summary of their comments.

