How much do investors trade because of name/ticker confusion?

We conduct a search for pairs of companies with similar names/ticker symbols. Between 12% and 25% of such pairs exhibit co-movements in trading turnover, which we attribute to investor confusion. We estimate that trades made by mistake contributed to 5% of the trading turnover. The three-hour CARs for the company chosen by mistake around the time intervals with extreme returns for the paired company are 0.5%. The confusion is highest for large companies and around time intervals with high turnover. We show that when the cause of confusion disappears, the co-movement in turnover also disappears. (C) 2019 Elsevier B.V. All rights reserved.