Stock prices are textbook cases of epiphenomena.
The prices are not causes. They are effects--they result from underlying values.
They tend to converge on those values in due course. But trading, by definition, means dumping them before they have a chance to assume those values.
Those values are actual causal factors. Prices, when different from values, are mere shadows.
The trader operates on the assumption that prices are the dog and values are the tail, when it is actually the other way around.