BlackRock, the New York-listed asset manager, has been forced to deny it is in trouble after market speculation over alleged losses from collateralised debt obligations and unsubstantiated rumours of a federal investigation wiped almost 8% off its share price.

Market talk of losses spread quickly on the US open, sending BlackRock stock to a low of $180 from Monday's close of $195.78. Shares in BlackRock have since recovered ground and were trading at $192.24 by 17:28 GMT.