Near 8:24 a.m. ET, Dow futures were down 115 points, S&P 500 futures were down 13 points, and Nasdaq futures were down 31 points.
On Tuesday, the Dow lost as many as 250 points and all the major indexes closed more than 1% lower.
The People's Bank of China let the Yuan fall 1.9% against the dollar today, repeating yesterday's surprising move that aimed to stimulate a slowing economy.
Along with stocks, oil had an ugly Tuesday, with West Texas Intermediate crude futures collapsing 5% in New York to a six-year low. The 12-member oil cartel OPEC reported that in July, its output surged to a three-year high.
Later today, we'll get the weekly numbers on US inventories from the Energy Information Administration. WTI was higher ahead of the opening bell, up about 1% near $43.60.
Also this morning, the report on Job Openings and Labor Turnover Survey will cross.