What Does Academic Research Say about Short-Selling Bans?

Abstract

As a reaction to higher market volatility due to the global COVID-19 pandemic, in March 2020 some financial regulators imposed short-selling bans on equity markets. Their argument is that short-selling exacerbates downward price movements, thus being responsible for heightened volatility and reduced market confidence. This paper reviews the academic literature on short-selling and short-selling bans, comparing the arguments against banning short-selling with the arguments in favour. We find that the evidence almost unanimously points towards short-selling bans being disruptive for the orderly functioning of markets, as they are found to reduce liquidity, increase price inefficiency and hamper price discovery. In addition, short-selling bans are found to have negative spillover effects on other markets, for example option markets. According to the literature, during periods of price decline and heightened volatility, short-sellers do not behave differently from any other traders, and contribute less to price declines than regular ‘long’ sellers. As research has shown that short-selling bans are more deleterious to markets characterized by a relatively high amount of small stocks, low levels of fragmentation, and fewer alternatives to short-selling, emerging markets should be particularly wary of bans on short-selling.