Information asymmetry could exist between the firm and the investors as well as among investors. If the information asymmetry between the firm and the investors is very high, all investors are largely uninformed, so information asymmetry between investors should be low. At the other extreme, if...

Purpose – This study aims to explore information asymmetry (IA) (as measured by the adverse selection component of the bid-ask spread) around S&P 500 revisions. Design/methodology/approach – The authors use adverse selection cost of trading measures to examine the effects of S&P 500 index...