Regulators on both sides of the Atlantic are combing e-mail records to investigate the role of credit-rating agencies in the sub-prime loan crisis.

Although house prices were no longer booming in December 2006, 'sub-prime mortgage' had yet to become a familiar term. It would be a few months before the risky-loans business would implode, with borrowers facing ruin, banks teetering on the brink of collapse and stock markets reeling worldwide.

At the credit-rating agencies that did so much to prop up the sub-prime industry, someone seemed to have a clear sense of what was coming. 'Let’s hope we’re all wealthy and retired by the time this house of cards falters,' an analyst wrote in a candid e-mail to a colleague.

That e-mail and dozens like it were disclosed last week in a 37-page report by America’s top financial watchdog, the Securities and Exchange Commission. In the corporate world, scandals have shown that when it comes to communications e-mails are deadly.

Sunday Times