08 crisis

The Postman from Salomon Brothers

In the late 1970s, the American housing market faced a quiet crisis. If you wanted to buy a home, you went to your local savings and loan association, a small neighborhood bank that took local deposits and turned them into home loans. But these banks were running out of money. They could only lend out what their neighbors deposited. If your local bank ran dry, you could not get a mortgage, no matter how good your credit was. Wall Street, with its trillions of dollars of global investment capital, was completely cut off from the average American homeowner.

Enter Lewis Ranieri, a loud, gregarious former mailroom clerk who rose to run the mortgage department at the investment bank Salomon Brothers. Ranieri looked at this local bottleneck and saw a massive business opportunity. He realized that if you could bundle thousands of individual home loans together, you could transform them into a standardized financial product that global investors would love to buy. This process of turning individual debts into tradeable securities is called securitization.

Slicing the Cash Flow

To make this work, Ranieri and his team had to solve a major problem: homeowners do not behave like predictable corporate bonds. Homeowners sometimes pay off their mortgages early, especially when interest rates fall and they decide to refinance. This is known as prepayment risk. If you are an investor expecting a steady stream of interest payments for thirty years, having all your money suddenly returned to you early ruins your math. Ranieri needed a way to make these unpredictable cash flows attractive to different kinds of investors.

The breakthrough came in 1983 with the creation of the Collateralized Mortgage Obligation, or CMO. Instead of just passing the mortgage payments straight through to investors, Ranieri's team sliced the pool of mortgages into different layers, called tranches. The first tranche would get paid off first, absorbing all the early prepayments. The middle tranches would only start getting paid once the first was completely retired. This meant investors could choose exactly how much prepayment risk they wanted to take on, turning a chaotic pile of home loans into highly structured, predictable investments.

We didn't just create a product; we created a whole new way of financing the American dream. But we also created a giant machine that eventually required more fuel than the world could safely provide.— Lewis Ranieri, reflecting on the evolution of securitization

Ranieri's invention was a wild success. It connected the global capital markets directly to the American suburban driveway. Suddenly, local banks did not have to hold onto the mortgages they made; they could sell them to Wall Street, get their cash back immediately, and issue new mortgages to the next family in line. This flooded the housing market with liquidity, making homeownership cheaper and easier to access than ever before. It was hailed as a democratic triumph of modern finance.

However, this machine had a fatal flaw that would only become clear decades later. When local banks held onto their own mortgages, they were very careful about who they lent money to, because a bad loan meant they lost their own cash. Once Ranieri's machine allowed banks to sell those loans to Wall Street immediately, the incentive to check the borrower's credit score began to evaporate. The link between the originator of the loan and the risk of the loan was broken forever.

• Securitization bridged the gap between local home buyers and global capital, turning illiquid individual debts into highly liquid, tradeable assets.
• The creation of tranches allowed Wall Street to engineer custom risk profiles, hiding the underlying messiness of human borrowing habits behind neat mathematical structures.
• By separating the people who sell loans from the people who hold the ultimate risk, securitization fundamentally weakened the incentive to ensure borrowers could pay.

Liar's Poker by Michael Lewis — This classic book offers a firsthand look at the chaotic culture of Salomon Brothers and Lewis Ranieri's rise during the birth of the mortgage market.