The Dow Jones Industrial Average came off its triple-digit rally, but still rose 46.17 points, or 0.37 percent, to finish at 12,460.96, led by Caterpillar and United Tech.
The S&P 500 slipped 0.14 points, or 0.01 percent, to end at 1,314.99. The Nasdaq erased 13.70 points, or 0.48 percent, to close at 2,831.02. Still, all three major averages are on pace to logging their biggest weekly gains of 2012.
The CBOE Volatility Index, widely considered the best gauge of fear in the market, ended below 22.
Among the key S&P sectors, telecoms and techs led the laggards, while utilities held modest gains.
In the final hour of trading, the Federal Reserve announced it wants U.S. banks to set aside more money to cover for unexpected losses, a move aimed at preventing another financial crisis. The news pushed major banks into negative territory, with Morgan Stanley and BofA leading the sector laggards.
Earlier, Bernanke told a congressional panel the central bank is "prepared to take action" if needed to boost the U.S. economy, but made no specific commitment to more easing. The Fed leader also said the economy continues to grow at a moderate pace but faces challenges from the jobs market as well as the debt crisis in Europe.
Bernanke's comments were a buzzkill to investors who had hoped for further policy action on the heels of several disappointing economic reports. On Wednesday, Fed's vice chair Janet Yellen along with several other regional Fed Presidents had made cases for further easing.
Gold slid below $1,600 an ounceafter Bernanke's comments, while the dollar rose.
“In fact, investors should be hoping that [Bernanke] doesn’t have to use QE3—that would indicate that the system is getting back on its feet by itself,” said Lawrence Creatura, portfolio manager at Federated Investors. “QE3 is a temporary salve and we’ve already used it twice—it has provided temporary relief of the symptoms but it does not treat the disease.”