The US economy is poised to be smacked by another wave of mortgage defaults that could cause as much damage as the subprime meltdown.

According to Credit Suisse, $1,000bn (£694bn, €772bn) of Alt-A and Option ARM mortgages – the dubious loans used to propel home sales through the final years of the housing bubble – are scheduled to have their interest rates reset from now through to summer of 2011.