Stocks advanced on Wednesday, lifted by energy and materials shares as commodity prices rebounded before the Federal Reserve's release of its assessment of the economy later in the session.

The Federal Open Market Committee, which sets interest-rate policy, will release minutes of its April 26-27 meeting at 2 p.m. (1800 GMT). Investors will look for hints about the Fed's QE2 stimulus program, which is widely expected to end in June, and will scrutinize the minutes for any disagreements among officials.

U.S. crude oil futures rose more than 3 percent to climb back above $100 a barrel after a weekly government report showed inventories of crude unexpectedly fell in the United States last week as refinery utilization rose.

Chevron Corp gained 2.2 percent to $102.60, providing the top lift to the Dow, while Exxon Mobil Corp advanced 1.6 percent to $81.71. The PHLX oil service sector index <.OSX> climbed 2.6 percent. The S&P energy index <.GSPE> added 2.1 percent and was the top-performing S&P sector.

The Reuters/Jefferies CRB index <.CRB>, a broad measure of commodity performance, rose 2.2 percent. Before Wednesday's advance, the CRB index was down more than 9 percent for the month.

The S&P materials index <.GSPM> gained 1.5 percent, boosted by mining company Freeport-McMoRan Copper & Gold , up 3.5 percent at $48.48.

The high beta names started the crisp turn about three weeks ago. That dragged down energy, materials -- that trade fell apart very quickly, said Peter Kenny, managing director at Knight Capital in Jersey City, New Jersey.

Now the question is: 'Is there still there an appetite for the risk trade?' The early morning action is telling us that it has not quite been extinguished.

Recent soft economic data has put investors on the defensive, increasing uneasiness about the recovery's strength and sending the benchmark S&P 500 down 2.1 percent for the month. Data on Tuesday showed weakness in factory output and housing starts.

The Dow Jones industrial average <.DJI> added 35.15 points, or 0.28 percent, to 12,514.73. The Standard & Poor's 500 Index <.SPX> rose 6.72 points, or 0.51 percent, to 1,335.70. The Nasdaq Composite Index <.IXIC> gained 17.16 points, or 0.62 percent, to 2,800.37.

Dell's shares jumped 5.3 percent to $16.74 after the PC manufacturer reported profits late on Tuesday that exceeded expectations. The company also raised its fiscal 2012 outlook for operating income.

But Staples Inc's shares tumbled 15.8 percent to $16.55 and ranked as the biggest drag on the S&P 500 after the office supply retailer slashed its full-year outlook on weak demand and higher costs.

Through Wednesday, 471 of the S&P 500 companies have reported earnings, with 69 percent posting results that beat Wall Street's estimates, according to Thomson Reuters data.

(Reporting by Chuck Mikolajczak; Editing by Jan Paschal)