Goldman Sachs' upper echelons may have been stunned by US regulators' decisions to accuse the bank of fraud on Friday, but they were quick in closing ranks around Lloyd Blankfein, its chief executive, and his top lieutenants.

Suggestions that the case – announced by the Securities and Exchange Commission without any advance warning – could cost Mr Blankfein his job after a series of blows to the firm's reputation were forcefully dismissed by Goldman executives over the weekend.

But they conceded they will be nervously watching the stock price this morning after shares plummeted by more than 12 per cent on Friday after the SEC's accusations that Goldman and one of its bankers misled investors in a complex collateralised debt obligation (CDO) tied to risky subprime mortgage loans.