Stock index futures were little changed on Tuesday as investors were reluctant to make bets after a rally in the previous session and as they waited to see if the Greek parliament would adopt a deeply unpopular austerity plan.

Greek lawmakers will vote Wednesday and Thursday on the austerity measures, which must be passed in order to receive the next payment of its bailout.

If the government does not get the next tranche, analysts said Greece could default on its debt, possibly sparking a Europe-wide crisis and potential credit market freeze similar to the one that came after the Lehman Brothers collapse.

Everyone's biggest fear is what could happen overseas, and we still don't know what's going to happen with that, said Christian Wagner, chief executive at Longview Capital Management in Wilmington, Delaware. We're lacking clarity, and when you lack clarity what you get instead is volatility.

While a default is seen as unlikely, concerns over the region have contributed to S&P 500 losses of more than 6 percent since the start of May. A thinly traded rise of almost 1 percent Monday could mean limited upside from current levels.

The S&P/Case-Shiller Home Price index for April will be released at 9 a.m. EDT and is seen falling 3.9 percent. Consumer confidence data and the U.S. Richmond Fed manufacturing services index are also on tap at 10 a.m. EDT and could offer signs of growth momentum. Confidence is seen holding roughly steady from the previous month.

Wagner said the housing market was so weak that poor Case-Shiller data wouldn't surprise or disappoint investors. It will just reinforce that housing is a major obstacle to the recovery, and at this point reinforcement is almost just as negative as disappointment, he said.

S&P 500 futures fell 0.5 point but were slightly 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 dropped 15 points, and Nasdaq 100 futures were off 0.75 point.

Microsoft Corp late Monday said it was making a big move into cloud computing this week by taking the wraps off a revamped online version of its hugely profitable Office software later in the day. Shares of the Dow component edged 9 cents higher to $25.29 in light premarket trading.

Nike Inc reported fourth-quarter earnings that beat expectations late Monday, and orders suggested robust strength for the future.

French search engine company 1PlusV is suing Google Inc for $417.7 million, alleging the company used its market dominance to block the development of alternative services.

Wall Street rallied after three days of losses on Monday, led by bank stocks after news of more favorable capital requirements and optimism over Greece's austerity plan.

(Editing by Jeffrey Benkoe)