Bearish indicators have been aplenty of late, and this one might be the most revealing: CEOs aren't too confident about the future. They're the least confident they've been in five years. The Goldman Sachs Confidence Index reveals that CEOs are worried about the credit markets, increased volatility, and mixed economic data. According to the Financial Times, "The headline reading for the global business outlook for the third quarter stands at 33 – down from the reading of 57 for the second quarter. A score of 50 marks the dividing line between executives who think conditions are improving and those who feel they are worsening."

This is pretty revealing. It's one thing to hear talking heads on CNBC lamenting the uncertainty surrounding the markets, but when top executives aren't optimistic and think things are getting worse, that's something I would pay a bit more attention to.

If CEOs aren't optimistic, we could see capital investments, share buybacks, and strategic acquisitions slow up considerably. Pessimistic CEOs become a self-fulfilling prophesy. If they think things are going to get worse, they probably will because CEOs have the power.