U.S. stock index futures fell on Thursday, pointing to a weaker open a day after stocks rallied, as investors grappled with mixed signals on whether the Federal Reserve would soon cut rates.

A Wall Street Journal article by correspondent Greg Ip said the Fed was in no rush to cut interest rates, stifling optimism that a cut was near after news of a letter in which Fed Chairman Ben Bernanke said the central bank was prepared to act as needed to ensure credit market troubles did not harm the economy.

Bernanke's letter to Democratic Sen. Charles Schumer of New York released on Wednesday, contributed to a late rally that helped stocks recover most of their losses on Tuesday.

Without quoting sources, Ip said Bernanke was keen to draw a distinction between keeping financial markets ticking over and ensuring a sound economy.

It's not necessarily a done deal that Mr. Bernanke is going to cut interest rates, and that's why we are having this sort of a mood swing in the market, said Peter Cardillo, chief market economist at Avalon Partners in New York.

S&P 500 futures fell 7.6 points, below fair value, a formula to evaluate pricing taking into account interest rates, dividends and time to expiration on the contract.

Dow Jones industrial average futures shed 58 points, and Nasdaq 100 futures fell 4 points.

Caution before a report on second-quarter gross domestic product, which will be scrutinized for clues about the economy's health and the outlook for a rate cut, also hampered sentiment. The GDP report is due at 8:30 a.m. EDT.

Banks are again among stocks that may exert downside pressure after Lehman Brothers cut price targets on Goldman Sachs, Merrill Lynch, Bear Stearns and Morgan Stanley.

In other news, tax preparer H&R Block Inc said it is renegotiating the planned sale of its Option One Mortgage Corp subprime lending unit to Cerberus Capital Management LP, a move that casts doubt on the largest U.S. tax preparer's ability to complete the sale.

The company also said its quarterly loss more than doubled.