Apartment Investment and Management Co., known as Aimco, said Wednesday it will cut 7 percent of its work force as part of an effort to cut costs.

The company would not say how many workers will be affected, but Aimco had 5,900 workers at the end of 2007, according to its past disclosures.

The company said it expects to take a fourth quarter charge in a range of about $21 million to $28 million to cover severance as well as writeoffs of its abandoned redevelopment projects.

The company has been selling properties and leaving a handful of markets as the real-estate market has soured. In the third quarter, Aimco raised $347.9 million, after debt repayments, from the sale of 45 apartment communities. It exited Hartford, Conn., Las Vegas, Nevada and Tucson, Ariz. during the third quarter. Net income was $163.6 million, compared with a loss of $21.4 million for the third quarter 2007.