Russell 1000 adds 10 energy stocks

Alpha Natural Resources., Atwood Oceanics Inc., Encore Acquisition Co., Exterran Holdings Inc., Hercules Offshore Inc., Mariner Energy Inc., Oil States International Inc., Petrohawk Energy Corp. and Whiting Petroleum Corp. were added to the Russell 1000, all moving up from the small-stock Russell 2000.

Key Energy Services Inc. is a new addition to the Russell 1000, having debuted on the market in October.

Cheniere Energy Inc. and Western Refining Inc. were removed from the large-cap index and moved to the Russell 2000.

Tacoma, Wash.-based Russell Investments realigns the Russell 3000 index once per year, tracking what it maintains is 99 percent of the U.S. equity market. That index is then broken down to 26 smaller indexes, including the widely watched Russell 1000 index of large capitalization stocks.

The makeup of the Russell indexes for the next 12 months was finalized after the closing bell Friday.