US house prices fell at their fastest rate in more than two decades during the third quarter, according to a measure of house prices released on Tuesday and widely followed by investors.

The S&P/Case-Shiller index suggests that house prices nationwide fell 1.7 per cent in the three months to October from the second quarter and were down 4.5 per cent year on year. Prices in 20 big cities were down on average by 4.9 per cent year on year.