U.S. stock index futures fell on Monday before a raft of corporate earnings, including Citigroup, as investors weigh whether corporate results and outlooks will be hurt by rising commodity costs.

Citigroup Inc , off 0.5 percent to $4.40 before the opening bell, is expected to report a drop in quarterly profit and revenue on Monday, as an uncertain trading environment and weak consumer loan demand hinder its efforts to move past the financial crisis. During the week of April 18, 110 S&P 500 companies are expected to report earnings.

The market is underwhelmed by the early earnings releases, said Peter Kenny, managing director at Knight Capital in Jersey City, New Jersey.

Input costs are driving more and more of the concern, and they are significantly less manageable than pushing consumer demand, or even industrial demand. It is a problem; it could really kind of make the rebound enter an anemic phase.

Halliburton Co , the world's No. 2 oilfield services company, advanced 0.9 percent to $47.25 in premarket trading after posting a first-quarter profit that beat analysts' estimates as oil companies increased spending on new projects to meet growing oil demand worldwide.

Eli Lilly & Co climbed 1.1 percent to $36.40 after the drugmaker reported better-than-expected first-quarter sales and earnings.

Also due to report on Monday is Texas Instruments .

China raised banks' required reserves for the fourth time this year on Sunday, stepping up efforts to fight high inflation.

Athens repeated it has no plans to restructure its debt, denying a Greek media report it had requested talks with its lenders as speculation that it would need a restructuring hit debt markets and the euro.

S&P 500 futures fell 9.6 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 fell 65 points and Nasdaq 100 futures fell 13 points.

Healthcare stocks will be in the spotlight after Swiss medical device maker Synthes confirmed it is in merger talks with Johnson & Johnson . Reports said the U.S. company was in talks to buy it for about $20 billion. J&J shares rose 0.7 percent to $60.97 in light premarket trade.

NYSE Euronext would likely want Nasdaq OMX Group to offer a substantial fee to guarantee that its takeover bid will pass antitrust muster before the NYSE is willing to engage in deal talks, two sources with knowledge of the matter said.

Renewed euro zone debt concerns hit European shares, sending a key index into negative territory for the year.

Stocks in Asia ex-Japan remained flat, with investors unconvinced that China's latest moves to cool its economy would hurt the global recovery.

(Reporting by Chuck Mikolajczak; Editing by Kenneth Barry)