Shares in Bear Stearns, Fannie Mae, Freddie Mac and other leading housing financiers plunged on Monday amid widening concerns about the health of the US mortgage market.

Fannie fell 13 per cent, Freddie 11.5 per cent and Bear 11.1 per cent as housing concerns helped send the broader market lower. The S&P 500 lost 20 points – or 1.55 per cent – to 1273.37, its lowest level in more than 18 months