Wash trades as a stock market manipulation tool

This study empirically investigates the profitability of one of the most widely used trade-based manipulation tools, namely wash trading. Using a unique account-level data set for the period 2003–2006 from the Istanbul Stock Exchange (ISE), we generate a measure for the usage of wash trades for each individual account and examine whether wash trading provides excess returns for investors. Our empirical results reveal that significant numbers of investors perform wash trades. In addition, we analyze the optimal percentage of wash trades at which investors maximize excess profits. We find that having up to 10% of total trades as wash trades is the most profitable range, with a 0.5% monthly excess return.