Health insurer WellPoint ( WLP) has put its pharmacy benefits management business up for auction, the Financial Times reports, citing people familiar with the matter.

A sale of the business could be worth anywhere from less than $1 billion to five times that amount, depending on the extent to which WellPoint and other insurers are willing to sign long-term customer contracts with any potential buyer, said one person close to the process, the newspaper reports.

WellPoint, which provides insurance under the Blue Cross Blue Shield brand, says its PBM business, which includes NextRx, is the fourth-largest in the United States.

The Financial Times reports WellPoint's business is likely to attract interest from CVS Caremark ( CVS), Medco Health ( MHS)and Express Scripts ( ESRX), and the sale process has been under way for months, according to people close to the matter.

WellPoint didn't have any immediate comment, reports the Financial Times.