Futures Gain, Lifted by Earnings; Citi Falls

U.S stock index futures gained Tuesday, boosted by a batch of better-than-expected earnings reports and as optimism grew that Spain may be getting closer to asking for a bailout.

Citigroup's CEO Vikram Pandit announced he is stepping down from his position at the investment bank. Michael Corbat will succeed Pandit. President and Chief Operating Officer John Havens also resigned. Shares tumbled in heavy pre-market trading.

Among earnings, Goldman Sachs edged higher after the banking giant reported quarterly results that beat analysts' expectations and increased its dividend.

Coca-Cola reported earnings that matched Wall Street expectations, but revenue fell slightly short, hurt by the stronger U.S. dollar.

Johnson & Johnson edged higher after the drugmaker reported quarterly results that beat analysts' expectations .

And newly-minted Dow component UnitedHealth reported earnings that were higher than a forecast the company gave earlier this month. The health insurer also boosted its full-year profit outlook.

IBM, Intel and CSX are slated to post earnings after the closing bell.

On the economic front, consumer prices rose 0.6 percent in September , according to the Labor Department, matching analysts' expectations and the prior month's reading.

Industrial output rebounded to 0.4 percent in September, according to the Federal Reserve. Analysts polled by Reuters had forecast a 0.2 percent rise compared to a 1.4 percent decline in August.

At 10 a.m., the National Association of Home Builders will publish its Housing Market Index for October. Economists polled by Reuters expect a reading of 41, up from 40 last month.

European shares were boosted by better-than-expected investor sentiment data from Germany and ongoing reports that Spain is preparing to seek a bailout package. The Spanish IBEX index remained firmly in the black.

—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter:@JeeYeonParkCNBC)

Coming Up This Week:

TUESDAY: Housing market index, News Corp shareholders mtg, Target media day, 2nd Presidential Debate; Earnings from IBM, Intel, CSX
WEDNESDAY: Weekly mortgage apps, housing starts, oil inventories; Earnings from BofA, PepsiCo, Bank of NY Mellon, Blackrock, Northern Trust, US Bancorp, AmEx, Ebay
THURSDAY: Jobless claims, Philadelphia Fed survey, leading indicators; Earnings from Morgan Stanley, Phillip Morris, Travelers, Union Pacific, Verizon, Fifth Third, Huntington Bancshares, KeyCorp, Nokia, Google, Microsoft, AMD, Capital One, Chipotle, E-Trade
FRIDAY: Existing home sales; Earnings from GE, McDonald's, Schlumberger, Honeywell, Edward Lifesciences