European shares were a touch lower on Wednesday as concerns over global growth were compounded by as a survey showing a seventh month of contraction for the euro zone's private sector in August, suggesting the bloc is likely to have slipped back into recession in the current quarter.

Japan's Nikkei average fell to a near five-week closing low on Wednesday as soft U.S. manufacturing data and construction spending added to concerns about a global economic slowdown.

The Labor Department releases revised Q2 Productivity and Unit Labor Costs at 1230 GMT. Economists in a Reuters survey forecast productivity to rise 1.8 percent versus a 1.6 percent rise in the preliminary Q2 report. Unit Labor costs are expected to increase 1.5 percent compared with a 1.7 percent increase in the preliminary Q2 report.

Nokia (NOK1V.HE) and Microsoft Corp (MSFT.O) will take the wraps off the struggling European company's most powerful smartphone on Wednesday, in what may be their last major shot at winning back a market dominated by Apple (AAPL.O), Samsung (005930.KS) and Google (GOOG.O).

The FBI said on Tuesday there was "no evidence" to support claims that hacking group Anonymous infiltrated an FBI agent's laptop and lifted a file with identification numbers for more than 12 million Apple products.

Facebook Inc (FB.O) promised not to sell stock to cover a nearly $2 billion tax bill and said it will allow employees to cash in their stock weeks ahead of schedule, moving to soothe nervous investors and its own staff as its share price spirals downward.

Automakers turned in their best August since before the 2007-09 recession, with U.S. monthly auto sales rising 20 percent from a year ago as consumers with aging vehicles showed more confidence in buying big-ticket items on easier credit terms.

General Motors Co (GM.N) began initial production of its first ever Chinese-designed car for the Indian market this week, a major step for the U.S. automaker as it tries to scale up in a market where foreign companies have struggled.

U.S. health regulators on Tuesday approved a Pfizer Inc (PFE.N) pill for a rare type of leukemia, another step in the company's effort to expand its oncology business.

Rupert Murdoch's News Corp (NWSA.O) announced it nominated Alvaro Uribe, former president of Colombia, and Elaine L. Chao, former U.S. secretary of labor, to its board.

U.S. airlines could place hundreds of orders for new jets on top of their recent wave of purchases -- leaving billions of dollars' worth of orders for U.S. manufacturer Boeing Co (BA.N) and European rival Airbus (EAD.PA) still to fight over.

Capital One Financial Corp (COF.N) said its top stakeholder ING Bank NV (ING.AS) intends to sell all of its stake in the company in a public offering.

U.S. tax preparer H&R Block is expected to post a $0.39 loss per share in its first quarter, steeper than the $0.37 recorded a year earlier. The company may discuss steps it is taking to boost its share in the digital tax filing market where it faces stiff competition from software company, Intuit.

The Dow Jones industrial average .DJI ended down 54.90 points, or 0.42 percent, at 13,035.94 on Tuesday, while the Standard & Poor's 500 Index .SPX was down 1.64 points, or 0.12 percent, at 1,404.94.

A rally in Apple helped the Nasdaq Composite Index .IXIC rise 8.09 points, or 0.26 percent, to 3,075.06, after the tech giant distributed invitations to an event in San Francisco on September 12, setting the stage for what is widely expected to be the release of the iPhone 5.

(Reporting By Francesco Canepa; Editing by John Stonestreet)

• A Permanent Economic Emergency