Lewis Ranieri

Lewis Ranieri worked at Salomon Brothers where he co-developed the mortgage-backed securities (MBS) market in the 1970s and 1980s alongside colleagues including Bob Dall. He created the MBS trading desk and helped develop the legal and financial structures that allowed banks to bundle mortgages and sell them as securities. This innovation created a multi-trillion dollar market that transformed housing finance globally. Ranieri became famous in Michael Lewis's "Liar's Poker" and has been referred to as the "godfather of mortgage finance". The structures he pioneered later contributed to the 2008 financial crisis when improperly underwritten mortgages were securitized at scale. His legacy illustrates the dual nature of financial innovation — the same structural mechanisms that improved mortgage market liquidity and expanded homeownership access for decades became the transmission vehicle for systemic risk when applied to poorly underwritten credit at unprecedented scale.