Mounting concerns on Wall Street that mortgage lenders might be hurt by increasing defaults and delinquencies sent investors fleeing Monday from some of the biggest names in the industry.

The meltdown among lenders that specialize in home loans to people with weak credit, known in the industry as subprime lenders, again ravaged stock prices. Financial institutions from Britain's HSBC Holdings to subprime leader Countrywide Financial sank amid reports of strained portfolios as loans went bad. Top U.S. banks and brokerages also saw their stocks decline.