Even though the U.S. government threw an $85 billion lifeline to troubled insurer American International Group, Inc. Tuesday, U.S. stocks took another beating Wednesday led by plummeting shares of investment banks Morgan Stanley and Goldman Sachs.

Amid a flurry of government-backed steps to fortify the U.S. economy, Fed chief Ben Bernanke told lawmakers Tuesday the economy continues to face "numerous difficulties" including turbulent financial markets, rising unemployment and housing troubles.