Few people have shaped modern finance as profoundly as Lew Ranieri. Starting in the mailroom at Salomon Brothers, he rose to lead the firm's mortgage trading operation in the late 1970s and 1980s, where he helped pioneer the mortgage-backed security, pooling home loans into bonds that could be bought and sold by investors around the world. The innovation transformed housing finance and launched the modern securitization market, a technique that would eventually spread across nearly every corner of the credit world. His era at Salomon was later immortalized in Michael Lewis's Liar's Poker. In this episode of War Stories over Board Games, Ranieri looks back on the early days of building an entirely new market, the resistance he faced along the way, and what it was like to help invent a cornerstone of modern finance.