Offer your thoughts or opinion on the input financial query or topic using your financial background.

Does a stock really dip in price on the ex-dividend date? And why would it do this?
This effect has much empirical evidence as googling "dividend price effect evidence" will show. As the financial economic schools of thought run the gamut so do the theories.  One school goes as far to call it a market inefficiency since the earning power thus the value of an equity that's affected is no different or at least not riskier by the percentage of market capitalization paid. Most papers offer that by the efficient market hypothesis and arbitrage theory, the value of an equity is known by the market at any point in time given by its price, so if an equity pays a dividend, the adjusted price would be efficient since the holder receives no excess of the price instantly before payment as after including the dividend since that dividend information was already discounted so would otherwise produce an arbitrage.