The Bid-Ask Spread and its Determinants for Stocks Traded on the Istanbul Stock Exchange

This paper examines the bid-ask spread and its determinants in the Istanbul Stock Exchange (ISE). The sample of 198 stocks is analysed for a period from June 1996 to May 1997. The proportional spread is found to be an important part of the transaction costs compared to the brokerage fees in Turkey. Even though there is no market maker in the ISE, the change in the proportional spread across volume and market value quintiles are similar to that observed in the markets with market makers. A negative relationship between measure of volume and proportional spread is observed. The spread in the afternoon session is found to be significantly higher than that in the morning session. Public’s inelastic demand to trade near the closure and information-related trading at the end of the day are considered to be explanations for the observed higher spread at the end of the day