U.S. stock index futures eased on Thursday as contraction in Chinese manufacturing and a downturn in Europe's service sector underscored the headwinds faced by the global economy, even as central banks aggressively step up stimulus measures.

Manufacturing in China contracted for an 11th straight month in September, according to a private sector survey of factory managers; in the euro zone, a downturn in activity in the service sector steepened this month at the fastest pace since July 2009.

The data looked set to pressure stocks at the forefront of economic activity, such as miners and energy companies. U.S. crude eased on Thursday to trade under $92 a barrel, dropping for a fourth day, while copper slipped from 4-1/2 month highs. Shares of aluminum producer Alcoa fell 1.4 percent.

S&P 500 futures fell 4.4 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 33 points, and Nasdaq 100 futures lost 6.25 points.

Losses were relatively light and the S&P 500 has rallied 7 percent since early August, reflecting a belief that monetary easing in the form of bond buying by the Federal Reserve and the European Central Bank would put a floor on the market.

European equities <.FTEU3> fell 0.3 percent on Thursday as the weak Chinese manufacturing data reignited global growth concerns, hitting miners, while euro zone banks continued to trim recent gains on uncertainty over whether, and when, Spain would apply for a bailout.

Bank of America Corp is planning to cut 16,000 jobs by year-end as it speeds up a company-wide cost-cutting initiative amid declining revenues, the Wall Street Journal reported on Wednesday. The bank's shares fell 0.9 percent to $9.21 in premarket trade.

Adobe Systems Inc , maker of Photoshop and Acrobat software, said Wednesday current-quarter earnings will decline or remain flat. Still, investors were heartened, sending shares up 2 percent to $33.75 in premarket trading. Analysts said fourth-quarter targets showed the company's transition was happening quicker than expected, which was positive in the longer term.

The Labor Department releases at 8:30 a.m. EDT (1230 GMT) first-time claims for jobless benefits for the week ended September 15. Economists forecast a total of 375,000 new filings, compared with 382,000 in the prior week.

Information services company Markit releases its U.S. flash Markit Manufacturing PMI for September at 8:58 a.m. ET (1258 GMT). Economists expect the PMI to read 51.5, the same as for August.

The Philadelphia Federal Reserve Bank releases September business activity survey at 10:00 a.m. ET (1400 GMT). Economists forecast a reading of -4.0, versus -7.1 in August. The release comes after a weaker than expected reading for New York manufacturing earlier this month.

(Editing by Bernadette Baum)