US STOCKS-Wall St lower as crude gives up gains
* Exxon, Chevron slide as crude gives up gains
* Pep Boys down after Bridgestone pulls out of buyout
* S&P 500 marginally positive for year
* Indexes down: Dow 0.30 pct, S&P 0.31 pct, Nasdaq 0.26 pct (Updates to open)
By Abhiram Nandakumar
Dec 30 (Reuters) - U.S. stock indexes were marginally lower on Wednesday as Brent crude retreated to near 11-year low.
Shares of Exxon and Chevron were down about 1 percent. Chevron was the biggest drag on the Dow Jones industrial average.
The S&P 500 energy sector is down 22.86 percent for the year, easily the worst performer on the index, followed by an 8.94 percent decline in materials, caused by a rout in commodities.
Trading volumes are expected to remain thin on the last trading days of the year. Continuación...