Wall Street stocks were poised for a modestly lower open on Wednesday, putting the three-day winning streak for the S&P 500 in jeopardy after weaker-than-expected euro zone economic data and ahead of a report on the U.S. housing market.

European shares fell for a second straight session as recession concerns increased after data showed the euro zone's service sector unexpectedly shrank and amid residual worries about Greece despite its success in getting a bailout.

I don't think anybody in their right mind thinks that they've solved Greece, but the bigger question is what do you do with the rest of these countries, they haven't gone away, said Joe Saluzzi, co-manager of trading at Themis Trading in Chatham, New Jersey.

The FTSEurofirst 300 <.FTEU3> index of top European shares was down 0.7 percent and the euro was slightly lower. <.EU>

But even with the weak European data, market sentiment remained positive in a market that has seen the benchmark S&P index rise 8.3 percent for the year on improving U.S. data and hopes the euro zone debt crisis could be held in check.

Investors will look at the National Association of Realtors' January existing home sales at 10 a.m. EST (1500 GMT) for more signs of a healing housing sector. Economists in a Reuters survey forecast 4.65 million annualized unit total versus 4.61 million in December.

You have seen some pickup in the housing market, but not anywhere near what they were expecting it to be or hoping it to be, and you really need a lot more growth than that, said Saluzzi.

S&P 500 futures fell 1.5 points and were slightly 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 lost 9 points, and Nasdaq 100 futures shed 4.5 points.

Dell Inc slumped 6.6 percent to $17.01 in premarket trading after the world's No. 3 personal computer maker forecast

revenue below expectations late Tuesday.

Toll Brothers Inc dropped 3 percent to $23 after the luxury homebuilder swung to a quarterly loss as fewer deliveries and more contract cancellations hurt revenue.

Garmin Ltd jumped 11.4 percent to $49.78 after reporting a better-than-expected quarterly profit as revenue from its personal navigation devices rose and demand for its outdoor and fitness products jumped.

TJX Cos Inc advanced 0.3 percent to $35.31 after the off-price retailer reported higher quarterly profit.

Fellow computer maker Hewlett-Packard Co is set to report earnings later Wednesday. The market expects a profit of 87 cents per share, down from $1.36 one year ago.

Other companies due to announce results later in the day include Express Scripts Inc and Analog Devices Inc .

According to Thomson Reuters data through Tuesday morning, of the 418 companies in the S&P 500 that have reported earnings, 64 percent have topped analysts' expectations.

Wells Fargo & Co is buying an energy lending business from BNP Paribas SA in the U.S. bank's latest acquisition from a European bank seeking to shrink its balance sheet.

(Reporting By Chuck Mikolajczak; editing by Jeffrey Benkoe)