RICHMOND, Va. — Circuit City says it's closing about 20 percent of its U.S. stores in an effort to return the nation's second-largest consumer electronics retailer to profitability.

The Richmond, Va.-based company said today it will shutter 155 of its more than 700 stores in 12 markets by Dec. 31, laying off thousands of employees.

Circuit City has had only one profitable quarter in the past year, posting a wider second-quarter loss in September with a 13.3 percent decline in sales at stores open at least a year. Its results have weakened amid a deteriorating retail environment and heightened competition from rival Best Buy Co. and others.

The company is reviewing its operations while exploring strategic alternatives.