Tue 08 Aug 2007World stocks slump on new US economy fearsWorld stocks slumped today amid reports of more damage from the teetering US subprime mortgage sector and falling US house prices.European shares snapped a seven-day rally to end lower after a series of newspaper reports suggested some investment houses, including Barclays, faced millions of dollars in exposure to asset-backed securities, stoking more uncertainty over the spread of the crisis in the US mortgage sector.