Borges, Maria Rosa2010-11-292010-11-292007Borges, Maria Rosa. (2007). "An arbitrage model for the stock price adjustment in the dividend period". Instituto Superior de Economia e Gestão - DE Working papers nº 9-2007/DE/CIEF0874-4548http://hdl.handle.net/10400.5/2577Following a dividend distribution, investors expect the stock price to decrease on the ex-dividend day. With no market imperfections, the price decrease should exactly match the amount of the dividend, thus eliminating all opportunities for profitable arbitrage. Allowing for different taxes on dividends and on capital gains results in a stock price adjustment ratio different from one, but there is still a unique equilibrium. With a simple model, considering four types of investors, we show that the consideration of transaction costs results in multiple possible equilibria (equilibrium zone), defined by the arbitrage boundaries of each type of investors. We also show that trading activity by the different types of investors is reflected in abnormal trading volume.engDividendArbitrageMarket EquilibriumTransactions Costsworking paper