Short Selling: The Impact of SEC Rule 201 of 2010
研究了SEC规则201对卖空行为的实际效果，发现该规则在正常时期抑制了卖空，但在2008年金融危机等波动时期并未约束卖空者，且未能带来公平估值、价格稳定或流动性提升等明确益处。
Abstract Despite its sizeable compliance costs, we are unable to document any clear benefits of SEC Rule 201 in ensuring fair valuations and price stability, promoting higher liquidity and execution quality, or preventing a sudden flash crash or prolonged market crises. Our daily and intraday analysis of data both before and after Rule 201 finds that short sellers are naturally more active before the occurrence of negative returns, not after significant price declines. Our simulation results show that Rule 201 further curtails short selling during normal periods, but is not binding on short sellers during the volatile period of the 2008 financial crisis.