Remember the monolines? Before Bear Stearns took centre stage, it was embattled bond insurers that worried Wall Street.

Ambac’s latest results should help to drag back the spotlight. An operating loss of $6.93 a share, on the back of sharply higher mark-to-market losses on mortgage-backed securities, was more than five times the consensus estimate. Ambac’s shares plunged by 43 per cent.