Investors balked early in Friday's session when comments from Bernanke didn't indicate a cut in the benchmark federal funds rate was imminent. However, they moved past some of their initial disappointment and appeared to concentrate on comments that the Fed would step in if needed.

Bernanke, speaking at the Fed's annual conference in Jackson Hole, Wyo., said the central bank will "act as needed" to prevent the credit crisis from hurting the national economy.

The major indexes fluctuated but by midday extended their gains after President Bush spoke about details of a plan to help borrowers facing trouble paying their mortgages.

"You've got all the speeches working for the market here," said Michael Church, portfolio manager at Church Capital Management in Philadelphia. "What we've seen in the last few weeks is that Ben Bernanke and the Federal Reserve are paying attention to what's going on. They will help correct the credit markets. For now, we're in a trading range and we have to sort through this mess."

According to preliminary calculations, the Dow rose 119.01, or 0.90 percent, to 13,357.74.