"> modeling a particular market force that has been difficult to capture in previous models. Empirical evidence shows that, when a stock return is fluctuating in the short term, there exists a market force that draws the fluctuating stock return back to its long-run equilibrium. This force is related to the concept of mean reversion, which is the tendency of a stock to return to its average price."

Talk of "market forces" and the like fall into the quantum voodoo school of economics, IMHO.

wait, is that right:

> the tendency of a stock to return to its average price

return to its historical average? As applied to all stocks, or certain, particular, mean-reverting stocks?

> a good approximation of the market force that restores a fluctuating stock return to equilibrium

Are we talking mean reversion here? A mathy example would be nice :-)