U.S. stock index futures were higher Wednesday, with the Dow poised to extend its gains a day after hitting an all-time high, following a better-than-expected private sector employment report.
Almost four years after the bear-market low, the Dow Jones Industrial Average pierced through levels last seen in 2007 to close at a record high of above 14,200 on Tuesday, amid signs of a strengthening economy and ongoing monetary support from the Federal Reserve.
(Read More: What the Pros Are Saying About the Market's Rally)
Meanwhile, some analysts warned that the rally may be the beginning of a bubble. U.S. shares are up almost 7 percent since the start of the year, European markets have gained about 5 percent, while in Asia, Japanese shares have soared almost 13 percent.
"I think stocks could very well rally through the rest of this year, even into 2014 based on this wave of money, but at some point it will pop and collapse, and that's what investors need to bear in mind," Jim Rickards of Tangent Capital, told CNBC Asia's "Squawk Box".
(Read More: Why Dow Record Could Be Good News for the Dollar)
On the economic front, private sector employment jumped by 198,000 in February, according to ADP's monthly report. Economists polled by Reuters expected a gain of 170,000. The report comes two days before the Labor Department reports the widely-followed non-farm payroll figures, with economists expecting a gain of 152,000.
The government will also release factory orders for January at 10 am ET. Economists polled by Reuters forecast a 2.2 percent fall in orders, after a 1.8 percent rise in December.
Among earnings, American Eagle Outfitters posted a higher quarterly profit, but shares tumbled after the teen apparel retailer handed in a disappointing current-quarter sales forecast, citing a tough economy.
Staples posted earnings that edged past expectations and also raised its quarterly dividend by one cent, but shares declined after the office supply retailer reported revenue below estimates and estimates a lower-than-expected full-year forecast, due to weakness in Europe and North America.
Big Lots rallied after the retailer topped Wall Street earnings and revenue expectations.
JCPenney slipped after Citi and Openheimer downgraded the retailer to "neutral" from "buy and to "perform" from "outperform," respectively. (Read More: Martha Stewart Denies Wrongdoing With JC Penney Deal)
European Union anti-trust regulators will hit Microsoft with a hefty fine for breaking a promise to offer consumers using its Windows system a choice of rival internet browsers, according to Reuters. The fine could run into hundreds of millions of euros, with regulators hoping to set an example after the software giant became the first company to break a promise made to end an anti-trust probe.
European shares traded higher, led by the telecommunications sector, boosted by reports that Vodafone is in talks with Verizon regarding a merger. Meanwhile, euro zone officials confirmed that the region's economy had shrunk by 0.6 percent in the fourth quarter of 2012, its five consecutive quarter of decline.
However, political uncertainty in Italy kept investors on edge amid a Reuters report that President Giorgio Napolitano is considering appointing a new technocrat government, led by a non-politician, as a way out of Italy's political stalemate.
The Federal Reserve is scheduled to release its Beige Book, its region-by-region assessment of the economy, at 2 pm ET. Crude oil inventories for last week will be released by the Energy Department at 10:30 am ET. Inventories rose by 1.13 million in the prior week.
Also on the economic front, weekly mortgage applications jumped 14.8 percent last week to its highest level since mid-January, reversing three weeks of declines as interest rates dropped, according to the Mortgage Bankers Association.
—By CNBC's JeeYeon Park (Follow JeeYeon on Twitter: @JeeYeonParkCNBC)
Coming Up This Week:
WEDNESDAY: Factory orders, oil inventories, Fed's Beige Book, Fed's Fisher speaks, Disney shareholders mtg, ExxonMobil shareholders mtg; Earnings from PetSmart, Vail Resorts
THURSDAY: Bank of England announcement, Challenger job-cut report, ECB announcement, international trade, jobless claims, productivity & costs, quarterly services survey, natural gas inventories, consumer credit, Fed balance sheet/money supply, chain-store sales, Green Mountain shareholders mtg, weekly rail numbers; Earnings from Kroger, Smithfield Foods, H&R Block, Pandora
FRIDAY: McDonald's sales, non-farm payrolls, wholesale trade; Earnings from Ann, Foot Locker
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