I owned Microsoft for a brief period at the beginning of 2009 with the stock in the teens. I remeber listening in on a conference call where Steve Ballmer said that he wants to preserve cash for opportunities and not buy back stock, even though Microsoft had 10's of billions of cash on their balance sheet. The stock went as low as $15 and Steve Ballmer preserved his cash. This quarter when the stock averaged about $28 Microsoft spent nearly $4 billion on buybacks.
I'm not saying that the stock is not worth $28 because I actually think the current price is reasonable. But why does he think its a buy now and it wasn't at nearly half the price? The skills necessary to operate a company and manage money are completely different. But CEOs are given the power to do both.