Declines in the previous session pushed both the Dow Jones Industrial Average and the S&P 500 into negative territory for the week, although the Nasdaq is still clinging to a marginal gain.
European shares edged lower with doubts over the strength of the recovery dampening investor sentiment. Asian indexes closed mostly in the red with Japan's Nikkei 225 seeing sharp declines.
There are no economic releases scheduled for Friday and the earnings calendar is relatively light. Hormel Foods and J.M. Smucker are among the companies set to report quarterly numbers.
Also on the earnings front, Dow component Hewlett-Packard and Nasdaq bellwether Dell released after-the-bell earnings reports Thursday. HP's fiscal third-quarter profit was in line with Wall Street estimates; the company had preannounced the quarter back on August 6. Dell reported quarterly profit of 32 cents a share, two cents above estimates.
Other after-the-bell reports included software maker Intuit, whose quarterly loss was narrower than expected, and retailer Gap, whose earnings topped estimates. Retailer Aeropostale saw its earnings match estimates but its revenues fall short, and Salesforce.com beat consensus with its second-quarter numbers.