MERRILL Lynch has become the latest banking heavyweight to succumb to the turmoil in the credit markets, as the US bank said that it would post a surprise third-quarter loss after writing down about $5 billion (£2.45bn) of subprime-related losses.

Merrill said the loss for the quarter would be as much as 50 cents a share after writing down about $4.5bn of loans linked to collaterallised debt obligations (CDOs) and subprime mortgages and about $463 million related to loan commitments to private equity firms.