Standard & Poor's has warned it may downgrade the eurozone bailout fund's AAA-rating once its review of eurozone countries' own ratings is complete.
The Bank of England is readying emergency funds designed to protect the UK economy from "unexpected shocks".
Rathbones fixed income manager Bryn Jones has said this week is the most important for Europe since the Second World War, as leaders try to resolve the debt crisis.
Barclays has offered to buy back £2.5bn worth of debt to boost its capital levels.
Ratings agency Standard and Poor's (S&P) said France and Germany are among 15 nations that have been put on "credit watch" due to fears over the impact of the debt crisis.
The S&P 500 has risen 1.7%, with European equity markets also holding onto gains after German Chancellor Angela Merkel and French President Nicolas Sarkozy reached accord on the debt crisis.
Gregor Logan, the former joint chief investment officer of New Star, said a leveraged balance sheet and poor performance from flagship funds caused the demise of the asset manager.
Negative market sentiment should not deter investors in US banks, said Ryan Brist, head of US investment grade credit at Legg Mason subsidiary Western Asset Management.
Franco-Belgian bank Dexia has secured temporary financing guarantees of €45bn from Belgium, France and Luxembourg, according to reports.