Short Sale Ban Research Articles

Do short-sale constraints inhibit information acquisition? Evidence from regulation SHO

We investigate how short-sale constraints influence investor information acquisition. Leveraging the U.S. Securities and Exchange Commission's (SEC's) Regulation SHO pilot program, we find that relaxed short-sale constraints lead to increased public information acquisition by investors. Investors acquire and process valuable information and utilize it to improve their short-selling decisions after the relaxation of short-sale constraints. We obtain similar findings using a quasi-natural experiment in China that lifted short-sale bans, supporting the external validity of our results. Collectively, our evidence demonstrates that reduced trading frictions promote information acquisition and contribute to price discovery.

Does short selling reduce classification shifting?—— Exploration of market-oriented governance mechanism

We empirically investigate the impact of short selling on classification shifting, exploiting the staggered lift of short-sale bans in China. Using a multi-period difference-in-difference research design, we find that the lift of short-sale bans mitigates the classification shifting. We also find that short selling alleviates the market's overpricing of the core earnings of firms engaging in classification shifting, thus reducing the expected benefits and motivations of firms for classification shifting. Further research shows that short selling has a more significant inhibitory effect on classification shifting in regions with developed financial intermediaries and it improves the persistence of core earnings.

The effect of the 2008–09 short selling sales ban on UK security equities in relation to market metrics of volatility, liquidity, and price discovery

In this study we look at the Financial Services Authority imposed short sale ban of UK financial equities in the 2008–2009 financial crisis to explore the effects of the short selling ban on liquidity, volatility, and price discovery on alternative portfolios of UK equity stocks. To this end we employ a control portfolio as well a portfolio of banned stocks. By using a GARCH model to explore the effects of short selling on portfolios’ returns volatility, we find a decline of volatility for selected UK financial stocks during the short sale restriction period. Further, we employ a bid-ask spread model to explore the effects of short selling on liquidity and find that liquidity deteriorates during the short sale ban period. We also employ a Wald-Wolfowitz Runs Test to investigate the effects of the short sale ban on price discovery and find that price discovery deteriorated during the short sale ban period. Finally, we examine the causal relationships among the market metrics in order to provide additional insight into the structure of the UK equity market during the period under study.

Is the Overheated Short-selling Stock Designation Regulation Properly Designed? Based on the Clustering Analysis of Overheated Short-selling Stocks

This paper examines whether the overheated short-selling stock designation regulation is effectively designed. The regulation prohibits short sales of overheated short-selling stocks for one day to call investors’ attention and prevent stock price declines. Comparing overheated short-selling stocks with control group, we find no statistically significant difference in their stock prices after the prohibition. This finding indicates that the one-day short sale ban is not effective in preventing stock price declines. We further show that the difference in short sale rates between overheated short-selling stocks and control group varies by types of overheated short-selling stocks. This result means that the regulation can stabilize short trading in certain types of stocks while it can also decrease market stabilization in other types. Lastly, we present the cluster of overheated short-selling stocks that is effective in preventing stock price declines through clustering analysis. It indicates that the effectiveness of the regulation is selective when a stock exhibits certain patterns, suggesting that the regulation should be designed more carefully.

Are stock and option trades substitutes or complements? evidence from the 2008 short-sale ban

Are stock and option trades substitutes or complements? evidence from the 2008 short-sale ban

The COVID-19 pandemic, short-sale ban, and market efficiency: empirical evidence from the European equity markets

This study looks at the inefficiency of stock indices of France, Italy, and Spain around their financial regulatory authorities’ short-sale ban during the COVID-19 pandemic crisis. The empirical analysis of this study provides evidence of price predictability of the basis of futures contract prior to the short-sale restriction. Moreover, the results show a significant underpricing in futures contracts of FTSE MIB and IBEX35 indices while the two months of short-sale banned period. These findings suggest that prohibiting short selling during the market downturn might undermine the stock markets’ efficiency and generate arbitrage opportunities for speculative investors.

Short Sale Bans May Improve Market Quality During Crises: New Evidence from the 2020 Covid Crash

Short Sale Bans May Improve Market Quality During Crises: New Evidence from the 2020 Covid Crash

Liquidity Effects of the 2020 European Short Sale Ban

Liquidity Effects of the 2020 European Short Sale Ban

Short Selling – On Ethics, Politics, and Culture

Abstract Lawyers and economists do not always speak the same language. Where economists present crisp and clear numbers, lawyers get lost in lengthy discussions about fairness and justice. Or so it seems. Arguably, the regulation of short selling illustrates a worrying clash of cultures. Economists understand short selling as a value-free market mechanism while (not only) lawyers suspect a profit, unfairly gained at the expense of others: “Short sellers not only profit from the misery of others, they also cause it”. In what follows, we address implications of this culture clash in the realm of ethics and politics. We conclude with a hypothesis, submitting that there might be traces of another clash to be observed when comparing regulatory cultures across countries. A preliminary look at data seems to suggest that short sale bans are less common in countries with a strong capital-market tradition and more common for countries which are newer to this game. If this holds true, important lessons are to be learned for the European Commission’s plan to set up a capital market union.

Short-Selling Equity Exchange Traded Funds and Its Effect on Stock Market Liquidity

AbstractWe examine short selling of equity exchange traded funds (ETFs) using the 2008 short-sale ban. Contrasting the previously documented contractions in bearish strategies during the ban, we find a significant increase in short sales of the largest, most liquid ETF, the S&P 500 Spider. We offer evidence suggesting that this upsurge was driven primarily by investors circumventing the ban. We show that the ban’s detrimental effect on stock liquidity was around 30% less severe for the Spider’s constituents. Our results suggest that ETF shorts can substitute for short sales of individual stocks, thereby alleviating short-sale constraints’ adverse effect on liquidity.

Dynamic Asset Pricing with Interactions between Short-Sale and Borrowing Constraints

Abstract This paper studies the joint effect of borrowing and short-sale constraints under heterogeneous beliefs and risk aversions. Although the constraints never simultaneously bind in equilibrium, interesting economics emerge in the anticipatory effects of potentially future binding constraints. In particular, the risk-free rate and Sharpe ratio experience endogenous jumps at a critical state, where two equilibria coexist. Moreover, a short-sale ban can lead to a lower stock price and higher volatility depending on the relative tightness between the constraints, and tightening the borrowing constraint during a short-sale ban can also make returns more volatile. (JEL G11, G12)

Does Short-Selling Affect Mutual Fund Shareholdings?

Using the gradual lifting of the short-sale ban in the Chinese stock market from 2010 to 2019 as natural experiments, the paper studies mutual funds’ strategies towards short-sales. The difference-in-difference regressions consistently show that mutual funds hold fewer shares when stocks are allowed to sell short, and their shareholding reduction towards short-selling is more intensive in stocks with higher valuation, larger market value, higher profitability, higher investment rate or more media coverage. These results are robust in short-term and long-term sample, annual data and classified funds. Our findings suggest that mutual funds generally dislike short-selling activities, and since short-sellers process negative information to alleviate stocks’ overvaluation, or spread pessimistic beliefs to undervalue high-quality stocks, mutual funds’ dislike towards short-selling reinforces in overvalued or high-quality stocks.

The unintended real effects of short selling in an emerging market

Exploiting the staggered removal of short-sale bans in China, we document unintended real effects of allowing short selling in an emerging market featured by concentrated ownership and weak investor protection. Pilot firms have worse short-term and long-term market performances after the removal of short-sale bans. Additionally, pilot firms undertake less risk and have worse performance following the launch of the program. The effect is stronger when controlling shareholders' private benefit is large and when corporate governance is weak. Faced with increased short selling threats, pilot firms cut capital investments and R&D expenditures, reduce equity financing, and lower debt ratios. Contrary to prior studies showing that short selling encourages value-enhancing risky investments in developed markets, our findings suggest that in emerging markets such as China, short selling can result in value losses by inducing firms to forgo profitable risky projects.

Informed Trading with a Short-Sale Prohibition

Using a rational expectations equilibrium framework, I evaluate the effects of a short-sale prohibition in an economy with asymmetrically informed investors who are identical except for their information sets. Relative to an economy in which short selling is permitted, the financial market is less informationally efficient under a short-sale ban even when the ban is not binding. This alters the risk-sharing environment and leads to an increase in information acquisition. Additionally, a short-sale prohibition increases market depth. Imposing a cost on short selling instead of a strict prohibition yields similar results. Novel empirical implications are identified. This paper was accepted by Karl Diether, finance.

The effect of short-sale restrictions on the information transmission of extended index futures trading

During the global financial crisis, two types of short-sale restrictions, i.e., the uptick restriction and the naked short-sale ban, were introduced in the Taiwan Stock Exchange (TWSE). This provides an opportunity to examine whether these two types of short-sale restrictions reduce the speed at which the overnight spot returns and the trading period spot returns adjust to the bad news revealed through the index futures returns during the post-close and pre-open extensions. The results of the threshold GARCH(1,1) model show that only the short-sale ban significantly reduced the speed at which the overnight spot returns react to the bad news revealed by the futures returns of the TWSE index during the pre-open extended session

Put-call parity violations and return predictability: Evidence from the 2008 short sale ban

We investigate the link between stock and options markets during the 2008 U.S. short sale ban. First, we find definitive evidence that the ban indeed caused stock overvaluation. Second, we show that the short sale ban caused a significant increase in put-call parity violations only in the direction of the short sale constraints and it significantly enhanced the stock return predictability of put-call parity violations. Third, the overvaluation is really large. A portfolio formed on the trading signal that the put-call parity violation is in the top quintile underperforms the lowest quintile portfolio by a statistically and economically significant abnormal daily return of 5.6% during the short sale ban period. We employ a novel and rigorous method of using TAQ intraday data to ensure that our high-low violation arbitrage portfolio as well as the five Fama-French factors used to estimate the abnormal returns are implementable by a hypothetical investor exempt from the shorting ban.

Asset Pricing with Heterogeneous and Constrained Investors

This paper studies the joint effect of borrowing and short-sale constraints under heterogeneous beliefs and risk aversions. Although the constraints never bind simultaneously in equilibrium, there is interesting economics in the anticipatory effects of potentially future binding constraints. In particular, the risk-free rate and Sharpe ratio experience endogenous jumps at a critical state, where two equilibria co-exist. Moreover, a short-sale ban can lead to a lower stock price and higher volatility depending the relative tightness between the constraints, and tightening the borrowing constraint during a short-sale ban can also make returns more volatile.

Directional information effects of options trading: Evidence from the banking industry

This study examines the transmittance of directional information from the options trading process to equity values and the mechanism in which informed option trades translate to underlying asset valuations. We construct proxies for positive (negative) informed trades and find that they are associated with a value premium (discount). We demonstrate that information asymmetries in the banking industry accentuate the price discovery role of option trades, especially negatively informed trades. The results are consistent with the arguments in Miller (1977), which contends that overvaluation is pronounced in securities that are short-sale constrained and highly informationally opaque. During the short-sale ban of financial stocks in 2008, negative informed trades have a positive effect on short interest, suggesting that value implications are the result of hedging-related behavior by market makers.

How Did Short Sale Ban Affect German Capital Market Risk?

The problem of short sale is a popular issue of stock trading and efficiency of pricing. Most regulatory authorities around the world adopted in the period 2007–2010 ad hoc bans on short selling. This paper provides an examination of an impact of the short sale regulation on the German capital market during crisis period 2008–2010. The purpose is to identify effects of the short sale regulation on level of systematic risk on German capital market and to investigate the discovery of stock prices of German blue chips at the period from May 2007 to April 2011 and three sub periods which demonstrate different regulatory approach to naked short sale regulation. The results suggest that short sale ban affects the level of systematic risk in the German market and prolongs a price reaction on new information. Further, short sale ban limits activities of investors with bearish view. After adoption of short sale ban the level of systematic risk increases and not only banned stocks are affected by the regulation. Finally, at the analyzed period the problem of negative information corporation in stock prices has arisen. Thereafter, the short sale ban is lifted the level of systematic risk decrease and there are not significant differences for banned and not banned stocks. Further, the price efficiency measured by autocorrelation also decreased after ban is lifted.

Are Shorts Equally Informed? A Global Perspective

Using a daily sample of 25 countries from 2006 to 2010, we examine whether information from shorts can significantly predict future stock returns across different countries. We construct seven shorting measures using past shorting transactions, and fees information in the lending market. The majority of our shorting measures significantly predict future stock returns. Interestingly, the relative importance of these variables varies substantially across countries. We explain the cross-country differences with variations in regulations on short selling, market quality and country development measures. The recent naked short sale bans strengthen the informativeness of shorting. The presence of a centralized stock lending market and low liquidity weaken the return predictability of short selling. In addition, higher country GDP per-capita, as well as country market openness, enhances short sales’ informativeness.