U.S. stock index futures indicated a higher open on Wednesday, with investors eyeing a buying opportunity after the worst start to September in 13 years, with stocks finishing down almost 3 percent as China and interest rate fears dominated.
Dow futures recovered to trade near session highs, up more than 150 points, after revised second-quarter productivity showed a rise of 3.3 percent, its strongest pace in one-and-a-half years, while labor costs fell 1.4 percent.
"We saw over 3 percent revision. That's good news in the sense there is more participation, there is more market output, a stronger economy emerging," said Peter Cardillo, chief market economist at Rockwell Global Capital.
"It just means no inflation and that's good news. The markets continue to say the (Fed) continues to miss its inflation target, which it has," he said.
Longer-end Treasury yields continued to tick higher after the productivity and costs data, with the 10-year yield at 2.18 percent and the 2-year yield at 0.73 percent.
Dow futures briefly held less than 100 points higher, off earlier gains of about 120 points, after the ADP report missed expectations slightly, showing creation of 190,000 private jobs versus expectations of 200,000.
"Bottom line, this is another good but not great number and is a continued comedown from the pace seen last year. It is the fifth month in the past six that has seen private sector job growth of less than 200,000," said Peter Boockvar, chief market analyst at The Lindsey Group.
Later in the day come July's factory orders data at 10 a.m., and the Federal Reserve's latest Beige Book at 2 p.m.
China is likely to remain in focus, but with a host of data releases Wednesday, traders will also be concentrating on indications of the timing of an interest rate rise, ahead of Friday's all-important job's report.
"Any hope that September could provide a little bit more stability for stock markets after the angst of August was quickly set aside yesterday as disappointing manufacturing economic data, not only from China, but Europe and the U.S. as well fed into an overwhelming narrative of pessimism surrounding the global economic outlook," said chief market analyst at CMC Markets, Michael Hewson.
On Tuesday, the major averages ended in correction territory, down nearly 3 percent in their third-largest daily decline for 2015. Stocks failed an attempt to cut losses in choppy trade prior to the close.
In their worst start to September in 13 years, the Dow Jones industrial average and had their worst first trading day of a month since March 2009. The Nasdaq had its worst first trading day of a month since October 2011.
Analysts attributed some of Tuesday's declines to a sharp reversal in oil prices. Weekly crude inventories from the U.S. Energy Information Administration at 10:30 a.m., ET, Wednesday, could provide fresh direction for the oil market and are in focus.
WTI crude oil was down over $1 or 2.3 percent at around 7:01 a.m. ET, having snapped a strong three-day rally to settle down 7.7 percent at $45.41 a barrel on Tuesday. Brent crude was down 93 cents at $48.63 per barrel after a larger-than-expected increase in inventories reported by the American Petroleum Institute Tuesday.
On the earnings front, before the bell Ambarella reported adjusted quarterly profit of 88 cents per share, beating estimates of 80 cents, while revenue was also above forecasts. However, the maker of video processing chips is seeing its shares under pressure, following a report warning of possible risks to GoPro's third quarter results. Ambarella is one of GoPro's key suppliers.
H&R Block posted a loss of 35 cents per share, 5 cents less than analysts had anticipated. Revenue beat estimates, and the company also announced a $3.5 billion stock buyback program.
Asian share markets went on a roller-coaster ride on Wednesday amid persisting concerns over the health of China's economy.
Violent swings were seen in China's major stock indexes, with the benchmark Shanghai Composite closing down 0.4 percent, as regulators stepped up rescue measures to support a wobbly stock market on Wednesday.
Earlier in the session, the key Shanghai index fell as much as 4.6 percent to an intra-day low of 3,019.0 before a wave of buying in late-morning trade pushed up prices in many sectors. Large-cap stocks such as infrastructure plays and banks ended the session higher, amid speculation that government-backed investors intervened.
—CNBC's Peter Schacknow contributed to this report