AIG has admitted the inaccuracies in the firm's accounts will leave a $1.2bn hole in its financial statements.

A cool $2.7bn will also be shaved off AIG's book value after it was forced to restate the last four years of accounting minus inaccuracies relating to transactions with insufficient risk transfer.

The 2004 accounts will not be published until the end of May, having been delayed for a third time.

New York attorney general Eliot Spitzer's probe into the insurer has revealed a series of accounting errors that have allowed capital gains to be converted into net investment income.

Ratings agencies took a dim view of AIG's second admission of accounting mistakes in a month. Moody's lowered AIG's long-term senior debt rating to Aa2 from Aa1, while Fitch slashed its rating to AA from AA plus.