Flying below the radar: Insider trading by executives below the top
利用挪威行政登记数据，研究发现上市公司非顶层高管买卖自家股票能获得异常回报，一个月内约50到100个基点，而买卖其他股票回报为负，排除了投资者能力解释。
To enforce insider trading laws, financial regulators require top executives to make their own-company trades public. One implication of this regulatory focus is that executives below the top fly under the radar. We use administrative register data from Norway to examine whether executives below the top in listed companies earn abnormal returns on purchases in own-company stock. We find evidence of abnormal returns on such trades, about 50 to 100 basis points at the 1-month horizon. The abnormal returns on purchases in other stocks are negative, making high investor ability an unlikely explanation.