CUPERTINO, Calif.— Apple Inc. has bought $14 billion of its own shares in the two weeks since reporting financial results that disappointed Wall Street, Chief Executive Tim Cook said in an interview.

Mr. Cook said Apple was "surprised" by the 8% decline in its shares on Jan. 28, the day after it reported lower iPhone sales than projected and warned that revenue in the current quarter might decline from the same period a year ago. Mr. Cook said he wanted to be "aggressive" and "opportunistic."

With the latest purchases, Mr. Cook said Apple had bought back more than $40 billion of its shares over the past 12 months, which Mr. Cook said was a record for any company over a similar span.

"It means that we are betting on Apple. It means that we are really confident on what we are doing and what we plan to do," said Mr. Cook, speaking in a conference room at the company's corporate headquarters here. "We're not just saying that. We're showing that with our actions."

Those purchases are part of Apple's previously disclosed plan to repurchase $60 billion of its own shares, Mr. Cook said. He said Apple bought $12 billion of the shares through an "accelerated" repurchase program, and $2 billion on the open market. He said Apple plans to disclose "updates" to its buyback program in March or April.