High-risk Mortgage Loans and Lending Practices

Lenders began to offer more and more loans to higher-risk borrowers, including illegal immigrants. Subprime mortgages amounted to $35 billion (5% of total originations) in 1994, 9% in 1996, $160 billion (13%) in 1999, and $600 billion (20%) in 2006. A study by the Federal Reserve found that the average difference between subprime and prime mortgage interest rates (the "subprime markup") declined from 280 basis points in 2001, to 130 basis points in 2007. In other words, the risk premium required by lenders to offer a subprime loan declined. This occurred even though the credit ratings of subprime borrowers, and the characteristics of subprime loans, both declined during the 2001–2006 period, which should have had the opposite effect. The combination of declining risk premia and credit standards is common to classic boom and bust credit cycles.

In addition to considering higher-risk borrowers, lenders have offered increasingly risky loan options and borrowing incentives. In 2005, the median down payment for first-time home buyers was 2%, with 43% of those buyers making no down payment whatsoever.

One high-risk option was the "No Income, No Job and no Assets" loans, sometimes referred to as Ninja loans. Another example is the interest-only adjustable-rate mortgage (ARM), which allows the homeowner to pay just the interest (not principal) during an initial period. Still another is a "payment option" loan, in which the homeowner can pay a variable amount, but any interest not paid is added to the principal. An estimated one-third of ARMs originated between 2004 and 2006 had "teaser" rates below 4%, which then increased significantly after some initial period, as much as doubling the monthly payment.

Mortgage underwriting practices have also been criticized, including automated loan approvals that critics argued were not subjected to appropriate review and documentation. In 2007, 40% of all subprime loans resulted from automated underwriting. The chairman of the Mortgage Bankers Association claimed that mortgage brokers, while profiting from the home loan boom, did not do enough to examine whether borrowers could repay. Outright fraud has also increased.