It happens by Thursday afternoon. Millions of people fill out their brackets with total confidence. Then a 12-seed takes down a favorite, and the whole thing falls apart. That is March Madness. The upsets are the point. But there is a version of that same upset in retirement. It is quieter, less obvious, and the consequences last a lot longer than a busted bracket. It is called sequence of returns risk. For anyone near retirement, or already in it, this is one of the important ideas to...