* Crude oil prices resume sliding
* Investors prepare for "quadruple witching"
* Red Hat up after FY rev forecast increase
* Futures down: Dow 33 pts, S&P 4.25 pts, Nasdaq 2.5 pts (Adds details, comment; updates prices)
By Abhiram Nandakumar
Dec 18 (Reuters) - U.S. stock indexes were set to open lower on Friday as a selloff in commodity markets showed no signs of easing.
Trading could be more volatile than usual on "quadruple-witching" Friday, when options on stocks and indexes as well as futures on indexes and single stocks expire.
Crude oil prices were heading for their third straight weekly loss as global oversupply continued to pile pressure. Exxon and Chevron shares were down less than 1 percent in premarket trading.
"Everyone is worried about the $1.2 trillion options expiration that takes place today and you're going to see some jimmying and jammying around that," said Jeffrey Saut, chief investment strategist at Raymond James Financial in Florida.
"But, the historical precedent of the December expiration is that it's usually pretty damn bullish," he added.
Saut said he expects the indexes to recoup its Thursday losses and rally towards all-time highs through Friday.
At 8:25 a.m. ET (1325 GMT), Dow e-minis were down 33 points, or 0.19 percent, with 46,790 contracts changing hands. S&P 500 e-minis were down 4.25 points, or 0.21 percent, with 295,415 contracts traded. Nasdaq 100 e-minis were up 2.5 points, or 0.05 percent, on volume of 46,169 contracts.
Global markets fell on Friday, with investors turning wary about the impact of a stronger dollar and weakening commodity prices on the global economy. U.S. stocks closed lower on Thursday, led by declines in energy and materials shares.
The dollar index, however, shed some of its post-Federal Reserve rate hike gains on Friday, after the Bank of Japan reorganized its stimulus program.
Carnival Corp shares were up 1.2 percent at $51.06, ahead of its quarterly results before the bell.
Qihoo 360 was up 1.8 percent at $73.10 after the Chinese mobile security software maker said it would be taken private for about $9.3 billion, including about $1.6 billion in debt.
Red Hat was up 6.5 percent at $84.02 after it raised its full-year revenue forecast for a second time.
Darden Restaurants was up 3.1 percent at $60.18 after its quarterly results.
Richmond Fed President Jeffrey Lacker is scheduled to speak at 12:30 p.m. ET. (Reporting by Abhiram Nandakumar and Aastha Agnihotri in Bengaluru; Editing by Don Sebastian)