CVS Caremark Corp., the largest provider of prescription drugs in the U.S., boosted its dividend by 22 percent and approved a share buyback for as much as $6 billion.

The quarterly dividend of 28 cents a share is payable Feb. 3 to holders of record on Jan. 23, the Woonsocket, Rhode Island-based company said in a statement. The share repurchase is effective immediately and will be completed over a period of several years.

Adjusted profit will be $4.36 to $4.50 in 2014, the company said. Analysts had projected $4.47, on average.

CVS rose 2.5 percent to $68.50 at 9:59 a.m. in New York. The shares added 38 percent this year through yesterday, compared with a 25 percent gain for the Standard & Poor’s 500 Index.