If stocks are in a bear market, the last thing investors need is to hear about it after the fact. It's as unhelpful as being told, "You should have been here yesterday."
The pullback in the Standard & Poor's 500 index hasn't yet reached the classic definition of a bear market, which is a decline of 20 percent or more. But by that measure, the drop is nearly here.
Are we headed for a bear market, and what should investors do? The answers are tricky.
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