* Brent crude falls about 2.4 pct
* Valeant slumps as CEO goes on medical leave
* S&P marginally up for the year
* Futures down: Dow 83 pts, S&P 9 pts, Nasdaq 12 pts (Adds details, comment; updates prices)
By Abhiram Nandakumar
Dec 28 (Reuters) - U.S. stock indexes were set to open lower on the first day of the last trading week of the year as oil prices continued to fall due to oversupply.
Brent crude was down 2.4 percent and were hovering near 11-year lows. Exxon's shares were down 1.5 percent at $78.14, while Chevron was down 1.7 percent at $90.47 in premarket trading.
"The 3 percent dive in crude oil this morning shows you that the sellers are still in control of the energy market and that's leading jitters on Wall Street, coupled with just normal digestive action after last week's strong gains," said Adam Sarhan, chief executive of Sarhan Capital in New York.
All three indexes posted their best weeks since mid-November last week, rising about 2.5 percent, led by a surge in energy stocks.
The S&P 500 is on track to end the year in the black, rising a marginal 0.1 percent so far in 2015, while the Nasdaq Composite is up 6.6 percent. The Dow Jones industrial average is down 1.5 percent.
At 8:25 a.m. ET (1325 GMT), Dow e-minis were down 83 points, or 0.48 percent, with 13,807 contracts changing hands. S&P 500 e-minis were down 9 points, or 0.44 percent, with 69,777 contracts traded. Nasdaq 100 e-minis were down 12 points, or 0.26 percent, on 12,490 contracts.
Trading volumes are expected to remain subdued through the week.
Global stocks ticked lower on Monday over fresh worries about Chinese growth after data showed profits at industrial companies in the world's second-largest economy fell in November for the sixth month in a row.
The London Stock Exchange was closed on Monday for Boxing Day.
Valeant was down 7.1 percent at $106.30 after the Canadian drugmaker said Chief Executive Michael Pearson is going on medical leave.
Fitbit was up 4.8 percent at $30.30.
Apple was down half a percent at $107.50. (Reporting by Abhiram Nandakumar in Bengaluru; Editing by Don Sebastian)