by Calculated Risk on 6/05/2009 09:20:00 PM

This weekend's 'This American Life' is about the rating agencies.

Here is preview (with a 7 min audio): Economy Got You Down? Many Blame Rating Firms. (ht Bob) A few excerpts:

"We hired a specialist firm that used a methodology called maximum entropy to generate this equation," says Frank Raiter, who until 2005 was in charge of rating mortgages at Standard and Poors. "It looked like a lot of Greek letters."
...
Managing director Tom Warrack was in the room when Standard and Poor's gave those mortgage-backed securities AAA ratings. He stands by that decision.

"I wouldn't say anything was missed," he says. "Never before in the history of the country, dating back to the Great Depression, have we had the type of nationwide market value declines, declines in home prices, and the associated default levels."

Warrack says that his agency required riskier loans to have more protections built in to receive the highest grade. He says the agency knew plenty about the mortgages inside those bonds. "We had lots of data," he says. "We had years' worth of data as to how borrowers perform over time."