Bottom line: Today's 2.8% drop is mostly a mirage — it's mechanical, not panic. But strip that away and you're left with a stock that has no

The missing 3% has a name: the behavior gap is the difference between the return a fund actually earns and the lower return its investors ac

"The stock is down 40%, it has to come back." You've heard this. You may have said it. It sounds sophisticated — it invokes statistical law.

Two portfolios both returned 15% last year. Identical result on paper. But Portfolio A drifted there steadily, while Portfolio B lurched fro