From 1977 to 1990, Leon Black was employed by investment bank Drexel Burnham Lambert, where he served as managing Director, head of the Mergers & Acquisitions Group, and co-head of the Corporate Finance Department. In 1990, he co-founded, on the heels of the collapse of Drexel Burnham Lambert, the private equity firm Apollo Global Management. Notable founders included: John Hannan, Drexel's former co-director of international finance; Craig Cogut, a Lawyer who worked with Drexel's high-yield division in Los Angeles; Arthur Bilger, the former head of the Drexel's corporate Finance department; Antony Ressler, who worked as a senior vice President in Drexel's high yield department with responsibility for the new issue/syndicate desk; and Marc Rowan, Josh Harris and Michael Gross, who all worked under Black in the mergers and acquisitions department.