Found at Chart Focus: The futility of trying to time the market.
The futility of trying to time the market
If a company consistently repurchased its shares when they were undervalued, its executives could reward loyal shareholders at the expense of inconstant ones. But timing the market is very hard to do. After a global technology business paid about $900 million to buy back its shares in 2004, for example, it spent increasingly large sums to do so just as prices rose. When they peaked, in 2007, it devoted upward of five times more money to repurchasing shares than it had in 2004. Yet the company spent less to buy them back in 2008 and nothing in 2009 or 2010, though prices had fallen by around 50 percent and profits remained strong.