WASHINGTON AP – With stock markets jittery over mortgage troubles, senators on Tuesday pressed the head of the Securities and Exchange Commission on what the agency is doing about complex mortgage securities and hedge funds, seen as posing risks to the financial system.

The recent turbulence on Wall Street, with last week being the worst for the Dow Jones Industrial Average in five years, appeared to loom as an unofficial guest during SEC Chairman Christopher Cox’s testimony before the Senate Banking Committee. The swoon was blamed on investors’ growing anxiety that problems in the market for high-priced home mortgages for riskier borrowers could spread to the broader economy.