Red means stop, and green means ... more capital. Greenlight Capital is a hedge fund that invests primarily in publicly traded North American corporate debt offerings and equities. Founded in 1996, the $6.5 billion Greenlight Capital also manages a fund of funds and a private equity fund through its affiliates, Greenlight Masters and Greenlight Private Equity Partners. It also operates Greenlight Capital Re, a property/casualty reinsurer. The company is led by activist investor David Einhorn, who has made a name for himself both in the boardroom and at the card table (as a finalist in the World Series of Poker).