Securitization: Mortgage banks hit by putback time bomb

That banks and mortgage servicers may have foreclosed on US homes without adequate documentation further blackens their already tarnished reputations. But the foreclosure scandal has increased the prospect of a far greater attack on mortgage securitization – one that even if it does not destroy the market altogether could cost the banks as much as $180 billion. Helen Avery, Louise Bowman and Peter Lee report.