Now that billionaire "activist investor" Carl Icahn has stopped trying to defeat the $25 billion Dell buyout (that finally became official today), he's turning his attention fully to one of the biggest companies in the world: Apple. Last month, Icahn revealed that his firm had made a significant investment in Apple, and today he took to CNBC and Twitter to reiterate his desires for the company to enact a major stock buyback. "Had a cordial dinner with Tim [Cook] last night," Icahn casually tweeted earlier this morning. "We pushed hard for a 150 billion buyback. We decided to continue dialogue in about three weeks."

Icahn went into more details in an interview on CNBC and made it pretty clear that he wasn't planning on leaving Apple alone any time soon. "I can't promise you the stock will go up and I can't promise you they will do the buyback," Icahn said. "But I can promise you that I'm not going away until they hear a lot more from me concerning this." He went on to call his proposed $150 billion stock buyback a "no-brainer" and said that "makes no sense for this company... not to do a major, major buyback." The stock market appears to be responding to Icahn's remarks, just as it did back in August when he first spoke out about Apple — as of this writing, the company's stock price is up 2.35 percent today.