Yet, investors are likely to question whether the weaker sales reflect a slowing economy and falling consumer confidence amid a falling housing market and high energy prices.
News that the trade deficit widened sharply in March, after improving over the past six months, also added to the pressure.
Futures for the Dow Jones Industrial Average were down 29 points at 13,355, while those for the S&P 500 fell 3.10 points to 1,512.
Nasdaq 100 futures were down 4.25 points at 1,908.
Among blue chips, Wal-Mart dropped 1.4% before the open after the giant retailer said April sales were down 3.5%. Analysts expected a 1.1% drop.
Overall, Thomson Financial was forecasting that April same-store sales would rise 0.4% compared with 6.5% in the same period last year.
The long list of other retailers that missed forecasts for April sales include Gap , J.C. Penney , Federated , AnnTaylor Stores , Nordstrom , Pacific Sunwear , New York & Co. , Limited Brands , Abercrombie & Fitch .
Among other Dow components, Merck rose fractionally after an editorial in the New England Journal of Medicine recommended a cautious approach toward Merck's cervical cancer vaccine, Gardasil.
American International Group rose slightly ahead of reporting earnings after the close.
Economy back in focus?
After being put on the backburner during the first-quarter earnings season, investors may again pay attention to signs of a slowing economy.
On Wednesday, the Federal Reserve left interest rates unchanged and referred to the slowing economy in its accompanying statement, even as it said inflation remained its number one concern.
But news that the U.S. trade deficit widened sharply in March could revive economic concerns. The deficit could lead to a downward revision of the already low first-quarter gross domest product to below 1%, according to Action Economics.
Rate attention turns to Europe, with the Bank of England likely to hike interest rates by a quarter point and the European Central Bank due to keep rates unchanged while hinting of a June hike.
The dollar rose against major rivals, even after the deficit numbers, following a drop in weekly U.S. jobless claims.
Crude oil futures rose 56 cents to $62.11 a barrel, and gold futures dropped $7.1 to $675.40 an ounce.
The Gap dropped 2.3% after reporting weaker than expected April sales.
Whole Foods tumbled 8% after reporting a profit decline and slowing same-store sales growth.
Rio Tinto fell 5.4% after Wednesday's rally from hopes that BHP Billiton will buy it, as the stock cooled in London and Sydney trade on Thursday.
By Nick Godt