Stock futures lower as earnings fears weigh

NEW YORK (Reuters) - Stock index futures fell on Tuesday as investors fretted over an earnings season that is expected to be grim and the health of the banking sector, highlighting the difficulties facing President-elect Barack Obama who will be sworn in later in the day.

Optimism over Obama's plan to push for a fresh stimulus package to stave off a worsening economy could help cushion the market.

But the banking sector could weigh heavily, taking a cue from global markets after Britain's Royal Bank of Scotland on Monday posted the biggest loss in U.K. corporate history, even as Britain launched a second bank rescue plan.

Banks have been at the epicenter of the credit crunch and resulting economic slowdown that has spread around the world.

"As excited as we are about the change in (the U.S.) administration and the history that we're making in this country and what fiscal stimulus might look like, we're also unfortunately realistically taking a good hard look at the earnings power of corporate America," said Arthur Hogan, chief market analyst at Jefferies & Co in Boston.

"If last week was any early indication, it won't be a very attractive earnings reporting season."

Companies expected to report quarterly results later in the day include Johnson & Johnson and International Business Machines .

S&P 500 futures fell 5.10 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 were down 80 points, and Nasdaq 100 futures lost 9 points.

Energy companies could also come under pressure as the price of oil slid below $34 a barrel after a deal between Russia and Ukraine cleared the way for the resumption of gas supplies to Europe. Shares of Exxon Mobil were down 2.7 percent at $76 in premarket trading.

(Editing by Chizu Nomiyama)