Analysts are focusing on the Institute for Supply Management's report on the services sector, a linchpin of the US economy.
Although activity is expected to ebb somewhat in September from the prior month's level, analysts still expect solid growth. A positive report could boost sentiment after this week's losses.
About 15 minutes into trading, the Dow Jones Industrial Average was down 0.1 percent at 26,057.82.
The broad-based S&P 500 gained 0.1 percent to 2,890.23, while the tech-rich Nasdaq Composite also climbed 0.1 percent to 7,795.28.
Stocks fell sharply Tuesday following a poor ISM report on manufacturing and dove again Wednesday following lackluster jobs data.
The reports sharpened fears that the US economy, which has outperformed other leading economies, could also be on the cusp of a significant slowdown or recession as the global economy cools, due in part to grinding trade conflicts initiated by US President Donald Trump.
Other key data will the National Retail Federation's forecast for the 2019 holiday shopping season and the official government jobs report for September, which will be released Friday.
Among individual stocks, Tesla tumbled 6.2 percent after it released third-quarter auto deliveries that lagged analyst expectations and raised doubts about the company's prospects for meeting full-year targets.
PepsiCo rose 2.7 percent after it reported better third-quarter earnings than expected thanks in part to strong sales of Gatorade sports drinks.