Don't worry, about 98% of the comments in these threads come from people who don't know a thing about the markets.
When you buy shares in a public company, you are buying a piece of that company's earnings. Buybacks concentrate earnings on fewer shares. If a company with 100M shares earned $100M, the earnings per share (EPS) is $1.00. If they take 50M share off the market through a buyback, EPS will rise to $2.00. If companies do nothing about the number of shares outstanding, over time the opposite will happen, as they grant shares and stock options to executives. This is called dilution. In part, buybacks are a strategy to reverse dilution.
So just to be clear about a couple of things: First, Apple is under no "pressure" do anything, so the headline of this article is fundamentally misleading. Second, the buyback that Icahn is proposing represents less than the amount of free cash Apple will generate in one year. So even if Apple accepted the proposal, they'd still end up the year with more than the $150B cash hoard that they are sitting on today.
Finally, Icahn is fundamentally correct. When a company generates cash far in excess of their ability to reinvest it in growing the company, then they need to find other ways to benefit stockholders. The two ways are dividends and buybacks. Apple is already doing both, so the only question is whether either or both will be increased. Last I heard from Apple, they were preparing to announcing something this month. It might come next week, at the earnings announcement.
