* Stock indexes poised for worst week since June
* Priceline gains on results, headed towards $1,000 a share
* BlackBerry open to going private, sources tell Reuters
* Futures down: Dow 40 pts, S&P 4.9 pts, Nasdaq 6 pts
By Ryan Vlastelica
NEW YORK, Aug 9 (Reuters) - U.S. stock index futures slipped on Friday, putting major indexes on track for their worst week since June, as investors found few reasons to buy with equity prices near record levels.
Wall Street has struggled this week, notching small moves in light volume, as an absence of trading incentives kept buyers at bay. Comments from Federal Reserve officials, which underlined confusion over when the central bank's stimulus policy would start to slow, further added to uncertainty.
"We're in a very slow month, and profit taking is coming back into the market," said Adam Hewison, president and chief executive at INO Inc in Annapolis, Maryland. "We think the Dow could test 15,400, but the bull market is still intact and we should make another run at all-time highs soon."
In the latest comments from a Fed official, Richard Fisher, president of the Federal Reserve Bank of Dallas, reiterated that the central bank will probably begin cutting back on its massive bond-buying stimulus next month, as long as economic data continues to improve.
While many investors are concerned that economic growth will stall without the Fed's help, shares have been supported by some strong earnings and encouraging data overseas.
In China, industrial output rose more than expected, adding to a string of data that indicated the economy may be stabilizing after an extended period of tepid growth.
S&P 500 futures fell 4.9 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 slid 40 points and Nasdaq 100 futures lost 6 points.
For the week so far, the Dow is down 1 percent, the S&P is down 0.7 percent and the Nasdaq is down 0.6 percent.
Online travel firm Priceline.com Inc rose 6.1 percent to $990.44 in premarket trading a day after it reported earnings that beat expectations and gave a strong outlook. Some analysts speculate the shares will cross $1,000 soon, which would be a first for a Standard & Poor's 500 stock.
Monster Beverage Corp shares fell 1.4 percent to $62.60 in light premarket trading after the company reported earnings Thursday that missed expectations.
Of 442 companies in the S&P 500 that reported results through Thursday morning, Thomson Reuters data showed that 67 percent topped analysts' expectations, matching the beat rate over the past four quarters. In terms of revenue, 53.6 percent exceeded estimates, more than the 48 percent rate over the past four quarters, but below the 61 percent average since 2002.
"Earnings have been good this quarter, but companies have wrung out every efficiency they can," said Hewison. "It's hard to see where more growth will come from."
June wholesale inventory data and sales data are due at 10:00 a.m. EDT (1400 GMT). Inventories are seen rising 0.4 percent while sales are expected to rise 0.7 percent.
U.S. shares of BlackBerry Ltd jumped 9.9 percent to $10.14 in premarket trading after Reuters reported that the company was warming to the idea of going private, citing sources familiar with the situation.
J.C. Penney Co shares fell 4 percent to $13.12. Late Thursday, activist investor Bill Ackman sent a letter to the retail chain's board, pushing to have a new chief executive named in the next 30 to 45 days.
Onyx Pharmaceuticals Inc said on Thursday that its process of seeking a buyer for the company is "ongoing with multiple parties engaged." Shares edged 0.7 percent higher to $128.34 before the bell.
Wall Street rose on Thursday, snapping a three-day string of losses, as a gain in Microsoft boosted tech shares.