Dow futures briefly drop 150 on weak data, Europe jitters

U.S. stock index futures turned lower on Wall Street on Wednesday as investors digest a mixed bag of earnings releases, economic data and Europe worries.

U.S. retail sales fell 0.3 percent in September, slightly more than the expected 0.2 percent decline. The producer price index for September fell 0.1 percent as opposed to expectations of a 0.1 percent gain.

Futures lost about 1 percent as investors were unnerved by word of another Ebola case diagnosed in the U.S., along with a more than 7 percent drop in the Greek markets that drove a flight to safety in German bunds, with the 10-year bond trading below 0.8 percent.

Read MoreGreek bond yields pass 7% as worries return

Meanwhile, German Bund yields fell to a record low on Wednesday as worries over a deteriorating euro zone economic outlook, fed by another credit rating blow for France, and "free falling" inflation expectations dominated the market.

Read MoreGreek PM wins confidence vote in parliament

Check what Europe markets are doing here.

U.S. stocks mostly advanced on Tuesday with the S&P 500 and Nasdaq Composite halting their worst three-day rout since 2011 as investors considered a mixed set of earnings from JPMorgan Chase, Citigroup and Wells Fargo. Intel released positive after-the-bell results and shares of the company gained more than 2 percent in late trading.

Read MoreWhy the stock market sell-off may be nearing an end

The Dow Jones Industrial Average finished flat while the S&P 500 added 0.2 percent and the tech-heavy Nasdaq gained 0.3 percent. However, the S&P energy sector was dragged down 1 percent after oil prices dropped more than $3 a barrel during Tuesday's session—the biggest percentage drop since November 2012.

On Wednesday, earnings are expected from American Express, eBay and Netflix after the bell. Prior to the start of trading Bank of America and Blackrock posted better than expected results.

Traders work the floor of the New York Stock Exchange.
Getty Images
Traders work the floor of the New York Stock Exchange.

Other economic data expected on Wednesday include business inventories for August at 10a.m. ET. The Federal Reserve's Beige Book report, an indicator on the state of the U.S. economy, is released at 2p.m. ET.

In other news, President Barack Obama will hold a video conference on Wednesday with British, French,German, and Italian leaders to discuss the Ebola epidemic in West Africa and other pressing international issues, the White House said.

A second Texas health-care worker who treated the first patient in the U.S. to be diagnosed with Ebola also tested positive for the disease, the Texas Department of State Health Services said.

Read MoreHow to trade Intel after earnings: Pros

Elsewhere, Asian markets erased early gains to trade mixed midday, as Chinese inflation data slowed more than expected to 1.6 percent in September, adding to concerns over a faltering global economic recovery. In Europe, meanwhile, markets traded slightly lower on the back of gloomy euro zone data on Tuesday.

Reuters contributed to this report.