Stock index futures dipped on Wednesday, as investors pondered whether the market would sustain a run-up seen in the prior session amid persistent concerns about recession and the financial sector.

Late on Tuesday, in his first speech to Congress, U.S. President Barack Obama tried to reassure Americans the country would emerge stronger from the crisis but analysts said he shed little light on how his administration would stabilize the economy.

Before the bell shares of Bank of America slipped 3 percent to $4.59 following news that Merrill Lynch & Co lost $15.84 billion in the fourth quarter, about $533 million more than previously estimated by Bank of America, which bought the Wall Street bank.

Last night's speech was nothing new. The market is starving for some real action, said Andre Bakhos, president of Princeton Financial Group in New Brunswick, New Jersey.

Yesterday's speech was a rehash of the obvious. We know things are not good. We need a plan of action. With each passing day there's less and less hope that Washington is able to do something about the economy and the banks.

S&P 500 futures fell 1.30 points, and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures shed 46 points, and Nasdaq 100 futures declined 3.50 points.

U.S. regulators are due to begin stress tests on Wednesday to determine how much capital banks need.

Federal Reserve Chairman Ben Bernanke said in testimony before Congress on Tuesday the significant value built up in the country's banks would be lost if the government owned them, easing investor fears that shareholders would be wiped out if they were nationalized.

His comments helped Wall Street snap back from 12-year lows and narrowly avert a breach that could have sent the benchmark S&P 500 <.SPX> to a fresh bear market low.

Even so, investors remain uncertain about how the government would relieve banks of money-losing assets and revive lending, added Bakhos. When it comes to financials, it's too early to buy and too late to sell.

The economic calendar features a report on January existing home sales, due at 10 a.m..

Bernanke is back on Capitol Hill at the same time to testify again on the economy, this time to the U.S. House Financial Services Committee.

(Editing by James Dalgleish)