Carl Icahn calls Apple a 'no brainer' investment as his stake grows to over $3B

Billionaire activist investor Carl Icahn took to his official Twitter account on Wednesday to reveal that he has purchased $500 million more shares of Apple stock in the last two weeks, and called his continued investment in the company a "no brainer."

Icahn's total stake in Apple grew to more than $3 billion as of Tuesday, up from his previous stake of around $2.5 billion. The comments made by Iachn Tuesday morning helped to send shares up nearly 1.5 percent in early trading.

But while Icahn was complimentary of Apple as an investment, he didn't make positive remarks about the company's board of directors. The investor said that he believes Apple's board is doing a "great disservice to shareholders by not having markedly increased its buyback."

Icahn has promised to publish an "in-depth letter soon" that will discuss his continued efforts to have Apple institute a larger buyback of its own shares. As of the end of the September quarter, the company had some $150 billion in cash, most of it stored overseas, and Icahn has said he would like to see all of it spent on a share repurchase program.

During fiscal 2013, Apple spent $23 billion of an expanded $60-billion share repurchase authorization, which contributed to combined dividend payments and repurchases totaling over $43 billion since the program was initiated some six quarters ago.

However, Icahn formally filed a shareholder proposal in November to push his repurchase plan. Apple, unsurprisingly, has recommended that investors vote against the proposal, saying that its board is already "thoughtfully considering options for returning additional cash to shareholders."

But Icahn's deep pockets and considerable sway among Wall Street ensure that his opinions on companies as large as Apple will be heard. In fact, his clout is so great that he even earned private meetings with Apple Chief Executive Tim Cook and Chief Financial Officer Peter Oppenheimer.