Indexes seesawed between modest gains and losses throughout the morning session. Technology stocks were the day's top gainers, supporting the Nasdaq, which outperformed other indexes. The Philadelphia semiconductor index <.SOX> was up 1.4 percent.
Banks were the biggest decliners after sharp gains in the previous session. The KBW Bank Index <.BKX> was down nearly 1 percent.
"We're seeing a lot of action in the Nasdaq and technology stocks. Those are flush with cash and have the least amount of risk," said Phil Streible, senior market strategist with MF Global in Chicago.
The Dow Jones industrial average <.DJI> added 20.51 points, or 0.18 percent, at 11,435.37. The Standard & Poor's 500 Index <.SPX> was up 0.76 points, or 0.06 percent, at 1,199.38. The Nasdaq Composite Index <.IXIC> put on 8.16 points, or 0.32 percent, at 2,557.10.
Obama will lay out a $300 billion plan to include tax cuts for the middle class and businesses and new spending to repair deteriorating infrastructure. Obama, scheduled to speak at 7 p.m. EDT, (2300 GMT) is staking his re-election hopes on a call for urgent bipartisan action.
Boosting the Nasdaq, Sandisk Corp jumped 5.6 percent to $39.74.
Among bank shares, Bank of America Corp fell 1 percent to $7.40, the second largest decliner on the Dow. The S&P 500 financial sector index <.GSPF> lost 0.7 percent.
Earlier, data from the Labor Department showed weekly jobless claims rose to 414,000 from an upwardly revised 412,000 in the prior week.
Separately, the trade deficit narrowed considerably in July, a positive signal for growth in the third quarter after a sluggish first half.
Federal Reserve Chairman Ben Bernanke will speak on the U.S. economic outlook to the Economic Club of Minnesota at 1:30 p.m. EDT.