The rating agencies made public computer models that were used to devise ratings to make the process less secretive. That way, banks and others issuing bonds — companies and states, for instance — wouldn’t be surprised by a weak rating that could make it harder to sell the bonds or that would require them to offer a higher interest rate.
But by routinely sharing their models, the agencies in effect gave bankers the tools to tinker with their complicated mortgage deals until the models produced the desired ratings.
“There’s a bit of a Catch-22 here, to be fair to the ratings agencies,” said Dan Rosen, a member of Fitch’s academic advisory board and the chief of R2 Financial Technologies in Toronto. “They have to explain how they do things, but that sometimes allowed people to game it.”
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