* Blackberry slumps after results
* Molycorp climbs after SEC investigation
* Accenture tumbles after earnings, outlook
* Futures off: Dow 34 pts, S&P 3.6 pts, Nasdaq 6.5 pts
By Chuck Mikolajczak
NEW YORK, June 28 (Reuters) - U.S. stocks were set for a slightly lower open on Friday, as weakness in technology shares outweighed gains in other shares spurred by relief a premature pullback of central bank stimulus measures was unlikely.
The S&P 500 has risen 2.6 percent over the past three sessions as economic data and comments from U.S. Federal Reserve officials soothed worries over an earlier-than-expected reining in of stimulative bond purchases by the Fed.
The benchmark S&P index had slumped as much as 4.8 percent in the days following a June 19 statement from the U.S. Federal Reserve, when Chairman Ben Bernanke said the Fed could start slowing its bond purchases later this year if growth was strong enough.
Accenture PLC tumbled 8.9 percent to $73.10 in premarket trading after the outsourcing and consulting services provider cut its full-year outlook and reported third-quarter revenue below analysts' estimates. The results also weighed on competitor IBM, which dropped 1.8 percent to $192.15 before the opening bell.
"Accenture's weak results both on revenues and guidance is weighing on the services group including IBM, which is one of the tech bellwethers, and that is causing futures to drop down from what was a strong overnight session," said Tim Ghriskey chief investment officer of Solaris Group in Bedford Hills, New York.
"Clearly, (Accenture's) outlook is weak and certainly the underperformance of technology as a sector in the stock market shows there are cyclical issues going on in tech as well as secular issues, rapid change occurring and purchasing managers holding back."
U.S.-listed shares of Research in Motion plunged 24.1 percent to $10.99 in premarket trading after the BlackBerry maker reported a fiscal first-quarter loss and forecast a loss in the current quarter.
Data expected on Friday includes the June index of manufacturing activity from the Institute for Supply Management Chicago at 9:45 a.m. EDT (1345 GMT). Economists in a Reuters survey forecast a reading of 56.0, from 58.7 in May.
Shortly after at 9:55 a.m. (1355 GMT), the Thomson Reuters/University of Michigan Surveys of Consumers final June consumer sentiment index is due. Economists polled by Reuters expect a reading of 82.8 compared with 82.7 in the preliminary June report.
The recent rally for the S&P 500 marks its best three-day performance since early January. The index is currently up 2.8 percent for the quarter and 13.1 percent for the year, though it is on track for its first monthly loss since October.
S&P 500 futures lost 3.6 points and were above 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 gained 34 points, and Nasdaq 100 futures shed 6.5 points.
Investors can expect a surge of volume at the close Friday when Russell Investments is due to set the final update for the annual reconstitution of its indexes.
Molycorp Inc jumped 8.2 percent to $6.07 in premarket trading after the rare earths producer said the U.S. Securities and Exchange Commission completed an investigation into the company and didn't recommend enforcement action.
Arch Coal Inc surged 8.3 percent to $3.90 before the opening bell after the company agreed to sell its Canyon Fuel subsidiary for $435 million in cash.