Futures Turn Flat After ADP Jobs Report

U.S. stock index futures shaved their gains to turn narrowly mixed Wednesday after a report showed private employers added less jobs than expected in March.

U.S. private employers added 158,000 jobs in March, falling short of economists' expectations for a gain of 200,000, according to payrolls processor ADP. February's private payrolls figure was revised up to an increase of 237,000 from the previously reported 198,000.

The ADP report comes ahead of the widely-followed government non-farm payrolls report, due Friday.

(Read More: Retail Investors Are Back! But Don't Hit 'Sell' Just Yet)

Earlier, the Mortgage Bankers Association reported that home loan applications dipped 4 percent last week due mainly to a decline in refinancing.

Meanwhile, the Institute for Supply Management's (ISM) non-manufacturing index, which tracks monthly changes in the services sector, is due out at 10 am ET. Economists polled by Reuters predict activity decreased slightly in March to 55.8 from February's one-year high of 56.0. A reading above 50 indicates a sector expansion.

Amna Asaf, an economist at independent research firm Capital Economics, warned the services index could mimic the fall seen in the ISM manufacturing index for March.

(Read More: US Manufacturing Growth Slows, Misses Forecast: ISM)

"Although expanding, the pace of economic growth in both the Dallas and Richmond regions appears to have leveled off last month. In addition, the three-month-on-three-month annualized growth rate of core retail sales has moderated," wrote Asaf wrote in a research note.

European markets were lower as Italy's political impasse continues and President Giorgio Napolitano's team of "wise men" attempted to formulate reform measures that can gain cross-party consensus.

(Read More: Italy's Bersani Drops Leadership Bid)

Vodafone slumped after Verizon Communications downplayed speculation that it is interested in buying or merging with the UK heavyweight. The denial follows media rumors that the telecommunications firm was working with rival AT&T on a breakup bid.

(Read More: Verizon Denies Intention to Merge With or Buy Vodafone)

Zynga soared after the social gaming company said it would begin offering real-money poker and casino-style games in the UK in the next few days.

Among earnings, ConAgra declined after the packaged foods company reported a 57 percent drop in earnings, hurt by costs related to its acquisition of Ralcorp.

Meanwhile, Monsanto gained after the seed company boosted its full-year profit guidance after reporting better-than-expected quarterly results thanks to strength in its global corn business.

Late on Tuesday, one of the Federal Reserve's most hawkish officials publicly locked horns with one of its most dovish, in a debate over the risks posed to inflation by the central bank's bold steps to spur growth. Policy dove Charles Evans, president of the Federal Reserve Bank of Chicago, said the Fed was still "missing tremendously" on the employment side of its dual mandate, while inflation remains well under its 2 percent goal.

(Read More: Fed Hawk Lacker and Dove Evans Face Off Over Inflation)

Crude oil inventories will be released at 10:30 am ET.

Meanwhile, the Nikkei 225 surged 3 percent on hopes that aggressive monetary stimulus measures will be announced at the Bank of Japan's policy meeting on Thursday. Central bank governor Haruhiko Kuroda is expected to substantially boost asset purchases,as well as buy longer-dated government bonds and commit to the open-ended purchase of assets.

—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)

Coming Up this Week:

WEDNESDAY: ISM non-mfg index, oil inventories, Fed's Williams speaks
THURSDAY: BoE announcement, Challenger job-cut report, ECB announcement, jobless claims, Fed's Evans speaks, Bernanke speaks, natural gas inventories, Fed's George speaks, chain-store sales
FRIDAY: Gov't jobs report, international trade, consumer credit

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