CVS Caremark Corp., the largest provider of prescription drugs in the U.S., forecast 2013 profit that topped analysts’ estimates as it benefits from new customers.

Adjusted profit next year will be $3.84 a share to $3.98 a share, Woonsocket, Rhode Island-based CVS said today in a statement. The average estimate of 21 analysts in a Bloomberg survey was $3.81.

Chief Executive Officer Larry Merlo has increased marketing and promotions to retain customers that it won when Walgreen Co. ended an agreement to provide Express Scripts Holding Co. shoppers with prescriptions. While Walgreen and Express Scripts have renewed their contract, CVS said last month it expected to keep at least 60 percent of the customers it gained during that dispute.

CVS rose 4.1 percent to $49.50 at 7:49 a.m. in New York. The shares had advanced 17 this year through yesterday.