Concern is also growing that other investment banks could face possible collapse. On Monday, shares in Lehman Brothers plunged 20 percent, its biggest-ever one-day fall. The Federal Reserve has reportedly urged other leading financial institutions to support Lehman Brothers in order to prevent a further economic crisis.

Market analyst James Hughes: “What the fears are, that the other banks which maybe haven’t written down so much, the fear is that they’re hiding these subprime mortgage issues, and maybe 'hiding' is the wrong word, but they’re putting them somewhere else, so we don’t necessarily get the whole picture. But, unfortunately, these things will come out, and that is the fear, that there’s going to be yet more writedowns and more problems coming along. And, of course, Bear Sterns is now turning into the US’s Northern Rock at the moment, and of course the fears are that there’s more going to go that way.”