British banking giant Barclays has had its credit rating downgraded from stable to negative.
The move reflects concerns over the impact of Bob Diamond's shock resignation on Tuesday.
Ratings agency Moody's said the departure of Mr Diamond, as well as chairman Marcus Agius and chief operating officer Jerry del Missier, in the wake of the rate-rigging scandal could lead to the break up of its powerhouse investment arm.
The downgrade comes ahead of a vote among MPs to decide whether Parliament or a judge should stage an investigation into the Libor-fixing affair.
Ex-Barclays chief executive Mr Diamond has admitted feeling "physically ill" when he discovered traders had fiddled the key rate but denied he was "personally culpable" for their actions.