One of Citigroup's top mortgage bankers warned management "repeatedly" about extreme risks that made "a mockery" of the bank's credit policy in 2006 and 2007, but said the bank continued to reassure mortgage investors and expand the business in spite of his calls for an investigation.

Six Citigroup employees were questioned by the Financial Crisis Inquiry Commission yesterday, including one who detailed his warnings to the board on mortgage risk, ahead of appearances by ex-executives Chuck Prince and Robert Rubin today.