Stock futures pointed to a higher open on Tuesday after positive comments on the economy and banks from Fed Chairman Ben Bernanke and news Bank of America sold its stake in a Chinese bank to help shore up its balance sheet.

Bank of America Corp sold about $7.3 billion worth of shares in China Construction Bank <601939.SS> to a group of investors, a source said, as the struggling U.S. bank sought to raise cash. Bank of America shares rose 2.3 percent to $13.25 in premarket trade.

Federal Reserve Chairman Ben Bernanke said late Monday the stress tests of how 19 major banks would endure a sharp downturn in the economy already appeared to be helping banks gain access to private capital, a key element in economic recovery.

The developments helped drive bank shares higher in premarket trade. Citigroup Inc traded up 2.3 percent to $3.95 and JPMorgan Chase & Co rose 1.9 percent to $36.52.

Bank of America raising capital is good sign, said Jack Ablin, chief investment officer at Harris Bank in Chicago, adding that upbeat comments from the Fed chairman help paint a brighter picture for the market.

The health of the banking sector has been key for the markets. Stocks rallied from 12-year lows in March after several lenders said they made money at the start of the year.

S&P 500 futures rose 4.50 points and were above 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 added 48 points, and Nasdaq 100 futures gained 6.75 points.

Ford , seen as the healthiest U.S. automaker, said late Monday it will sell 300 million common shares and use part of the proceeds to pay off its health-care obligations to the United Auto Workers union. Ford shares fell 3.5 percent to $5.87 in premarket trade.

The U.S. trade gap widened less than expected in March as exports fell 2.4 percent and imports dropped for the eighth consecutive month, U.S. government data showed.

Since reaching 12-year closing lows in early March, the Dow Jones industrial average is up 30.1 percent and the S&P 500 is up 36.4 percent.

(Reporting by Edward Krudy; editing by Jeffrey Benkoe)