The Dow Jones - AIG Commodity Index, which serves as the underlying benchmark for several popular index mutual funds and exchange-traded funds, is going through its annual rebalancing.

While gasoline and natural gas will slip some from last year's weightings, crude oil's ranks will gain. So will wheat, copper and nickel, to name a few. 

Target weights for constituents to be implemented this month, spread over a five-day period ending at the close of business on Jan. 15, will be (compared to 2008 weightings):

• Natural Gas: 11.89% (12.24%)

• Crude Oil: 13.75% (13.16%)

• Gasoline: 3.71% (3.78%)

• Heating Oil: 3.65% (3.82%)

• Live Cattle: 4.29% (4.89%)

• Lean Hogs: 2.39% (2.55%)

• Wheat: 4.79% (4.70%)

• Corn: 5.72% (5.66%)

• Soybeans: 7.59% (7.62%)

• Soybean Oil: 2.88% (2.81%)

• Aluminum: 6.99% (7.11%)

• Copper: 7.30% (7.04%)

• Zinc: 3.14% (3.03%)

• Nickel: 2.88% (2.79%)

• Gold: 7.86% (7.40%)

• Silver: 2.89% (2.72%)

• Sugar: 2.99% (3.19%)

• Cotton: 2.26% (2.48%)

• Coffee: 2.97% (3.00%)