Investment bank Goldman Sachs is to be investigated after US authorities issued fraud claims against it, the City regulator said today.

The Financial Services Authority (FSA) said it would launch a "formal enforcement investigation" into Goldman in relation to the Securities and Exchange Commission allegations in the US.

Prime Minister Gordon Brown has called for a special investigation into Goldman Sachs after reports that it is to rack up a bonus pot of £3.5 billion for the first quarter and he accused the bank of "moral bankruptcy".