In response to Icahn, Apple reiterates plans to review share buyback program annually

"We always appreciate hearing from our shareholders," Apple said in a statement to CNBC. "Since 2013 we've been aggressively executing the largest capital return program in corporate history. As we've said before we will review the program annually and take into account the input from all of our shareholders."

Earlier Thursday, Icahn published a letter in which he said he believes shares of Apple are "dramatically undervalued." Based on his estimates, he believes the company should currently be trading at $203 per share, or about double where it currently sits.

Given his estimated 50 percent discount, Icahn believes now would be a prudent time for Apple to spend its more than $130 billion in net cash on itself, buying shares at a discount before they trade higher.

Icahn's letter was a glowing endorsement of Apple, saying that he expects continued strong sales of the iPhone. He's also hopeful for the upcoming Apple Watch, and even predicted that the company could launch a full-fledged television set years down the road.

The praise from Icahn helped shares of Apple stay in the positive throughout trading on Thursday, even as the Dow Jones Industrial Average tumbled more than 300 points. Both it and the Nasdaq were off more than 1.7 percent in Thursday afternoon trading.

Apple first announced its dividend share and repurchase program in March of 2012, and at the time pledged to spend $45 billion on itself over three years. The company increased the program to $100 billion a year later.

Then again this April, Apple announced it would once again increase its buyback efforts, and the company also revealed it would undergo a 7-for-1 stock split that eventually came to pass in June. Based on Apple's current annual schedule, the company would likely revisit its buyback efforts once again, and take into consideration the requests of Icahn and others, following its March 2015 quarter.