Derivatives traders have been shocked by a $712 million revaluation loss at Standard Chartered after the bank changed the way it calculates counterparty risk – a switch that lagged the rest of the industry by as much as a decade.

A spokesperson for the bank says Standard Chartered's predominantly emerging markets portfolio lacked the data that would have allowed it to change its approach to credit valuation adjustment (CVA) earlier. Insiders claim the bank's traders have long supported a change