U.S. stock index futures pointed to a lower open on Wall Street on Wednesday, as investors were set to book recent gains ahead of key macroeconomic data on jobs and manufacturing.

* Investors awaited the ADP private sector employment data for May, due at 8:15 a.m. EDT, the ISM non-manufacturing business activity index, due at 10 a.m. <1400 GMT>, and monthly factory orders also due at 10 a.m.

* (The data) will cancel each other out in terms of investor views ahead of where the market is heading, said Rick Meckler, president of LibertyView Capital Management in New York.

Investors at this point are weary a little bit of those numbers and have shifted their focus to the individual prospects of companies and how it projects to earnings.

* S&P 500 futures fell 5.10 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 40 points, while Nasdaq 100 futures fell 6.5 points.

* Aetna Inc shares slid 9.7 percent to $24.63 in premarket trade after the health insurer cut its 2009 forecast late Tuesday, citing higher projected medical costs for its commercial business serving employers and lower revenue from its Medicare plans for seniors.

* Valero Energy Corp tumbled 9.6 percent to $20.24 after the largest U.S. refiner said Tuesday it would post a second-quarter loss due to weak market conditions and indefinitely delay two expansion projects.

* Credit Suisse turned more cautious on equities, taking its equity weightings down to benchmark from overweight. The firm wrote it remained concerned about the economic backdrop and that a recent rise in bond yields had undermined their valuation.

* European shares slipped in midday trade on Wednesday after hitting a five-month high the prior session as the banking sector extended losses along with a pullback in oil and commodity shares.

* Asian shares rose to new eight-month highs, as U.S. home sales data boosted optimism that the global economy is through the worst, while the dollar struggled to come off its latest set of lows for the year.

* U.S. stocks rose for a fourth straight day on Tuesday as an upbeat report on home sales bolstered hopes for an economic recovery as well as for shares in construction companies. But a selloff in financials on worries about the dilutive impact of recent stock offerings limited a broader advance.

The Dow Jones industrial average <.DJI> added 19.43 points, or 0.22 percent, to 8,740.87. The Standard & Poor's 500 Index <.SPX> gained 1.87 points, or 0.20 percent, to 944.74. The Nasdaq Composite Index <.IXIC> rose 8.12 points, or 0.44 percent, to 1,836.80.

* Since reaching 12-year lows on March 9, the Dow is up 35.1 percent and the S&P has risen 41.7 percent.

(Reporting by Chuck Mikolajczak; editing by Jeffrey Benkoe)