US investment bank JP Morgan Chase has been fined US $920m (€688m) by regulators for “serious failings” over the London Whale trading scandal.

JPMorgan Chase & Co, the biggest US bank, said it had lost $5.8bn (€4.7bn) in 2012 from disastrous credit bets and that traders might have tried to conceal the extent of the losses earlier this year.

The losses racked up by disastrous trades at the London office of America’s biggest bank have more than doubled to £2.8bn (€3.5bn), it emerged today.

America’s biggest bank is expected to accept the resignation of one of the highest-ranking women on Wall Street after it lost $2bn in a trading blunder, a person familiar with the matter said.