Stock Splits to Profit Insider Trading: Lessons from an Emerging Market. Richard Zeckhauser, February 28, 2017, Paper, “Stock splits have long presented financial puzzles: Why are they undertaken? Why are they associated with abnormal returns? Abnormal returns, particularly those coming shortly before a split’s announcement date, should raise strong suspicions of insider trading, particularly in nations with weak regulatory structures. We examined the 718 split events in the emerging stock market of Vietnam from 2007 through 2011. We found evidence consistent with illegal insider trading, particularly in firms that were vulnerable to insider manipulation and, therefore, more likely to split their stocks. When vulnerable firms’ stocks did split, they provided significant excess short-term returns.Link