Does Insider Trading Really Move Stock Prices?
分析伊万·博斯基在雀巢收购卡内森公司前的内幕交易，发现其交易对股价的影响与普通交易无显著差异，挑战了内幕交易促进价格发现的观点。
Prior studies have reported a positive correlation between insider trading and stock price changes implying that insider (i.e., informed) trades affect price discovery differently than non-insider (i.e., uninformed) trades. Based on these results, various scholars have argued for the legalization of insider trading to facilitate rapid price discovery. We analyze the trading activity of a confessed inside trader, Ivan Boesky, in Carnation's stock just prior to Nestle's 1984 acquisition of Carnation, and find that our tests are unable to distinguish the price effect of Boesky's (i.e., informed) purchases of Carnation's stock from the effect of non-insider (i.e., uninformed) purchases. Our conclusion survives extensive robustness tests and has methodological and public policy implications.