Wall Street stocks fell on Thursday as concerns about further losses on mortgage-related assets and the prospect of increased regulation sent financial stocks to their biggest one-day falls since the start of the credit crisis.

Since July 15, the S&P 500 has rallied more than 3.1 per cent, triggered by falling oil prices and a 21.5 per cent gain for financial shares after surprisingly solid results from JPMorgan and Wells Fargo.