Warren Buffet and James Dimon recently published an article in the WSJ saying public companies shouldn't give guidance in quarterly reports.
From what I understand, they're saying that if a company tells everyone what to expect from them, then people will pull their money out of the company if it does worse than what the company expected, and throw their money in if it does better. This makes the market more unstable because people are pulling out/throwing in their money all at once.
So... why do companies do this? Why do companies give guidance to begin with?