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This paper aims to investigate the implementation of the short selling ban policy imposed by the Italian stock exchange on health-care stock prices, as a tool to mitigate COVID-19 price effects. Important contributions are in terms of assessing the effect of the temporary short selling ban on restricted health-care stocks; the effect of COVID-19 cases and crude oil price volatility onto health-care stocks; and whether COVID-19 resulted in a change in the risk and average stock price of health-care stocks.

The methodology involves impulse responses to capture the shock of the short selling ban onto health-care stocks, and Markov switching regimes to capture the effect of COVID-19 onto the risk and prices in the health-care industry. Daily data from 9 November 2018 till 23 December 2020 is used.

Findings suggest there were significant changes in average prices in health-care technology and health-care services stocks before, during and after the short selling ban. Shocks to the number of COVID-19 cases and crude oil price volatility impacted health-care stocks but lasted only for a few days. While daily changes in the number of COVID-19 cases impacted some health-care stocks in the presence of a two-state Markov regime, insignificant coefficients and relatively low duration suggest that the short selling policy did not significantly change the average price and risk in health-care stocks to explain a two-state regime in the health-care industry.

Insignificant coefficients in a two-state Markov regime reinforce that short-selling policies have a short-lasting effect onto health-care equity prices. The findings are limited by the duration of the short selling policy, the pandemic event and the health-care industry.

This is the first study to look at the impact of early COVID-19 and short selling ban policy on health-care stocks.

The authors investigate the 2008-2009 short-sales ban in Korea, one of the most comprehensive and restrictive short-selling bans worldwide. The purpose of this paper is to examine: whether the ban stopped a destabilizing effect, if there was any, of short-selling activities; whether the ban improved or deteriorated the informational efficiency or the price discovery process of the stock market; and whether the ban had any impact on market liquidity.

Multiple regression; vector autoregression analysis; and generalized autoregressive conditional heteroskedasticity analysis.

The authors find no evidence that short-sales have a market-destabilizing effect and thus, restricting short-selling has a market-stabilizing effect. On the contrary, the short-selling ban is associated with an increase in return volatility and a deterioration of the price discovery process, particularly for the stocks without derivatives traded on them. The authors also find evidence of a liquidity decrease for short-sale intensive stocks. However, the evidence is inconclusive as to whether the market efficiency and liquidity changes are solely the result of the short-sales ban or the compound effects of both the ban and the concurrent progress of the financial crisis.

The literature does not provide a conclusive view on the effects of short-sales or restrictions thereof on the stock market. Also, the existing research on recent worldwide shorting bans often lack empirical scope (e.g. 32 stocks for UK; three weeks for USA). In contrast, the short-sales ban in the Korean stock market, one of the most comprehensive and restrictive short-selling bans worldwide, lasted for eight months for all the listed stocks and is still in effect for financial stocks. The authors find no evidence that short-sales have a market-destabilizing effect and thus, restricting short-selling has a market-stabilizing effect.

The purpose of this paper is to examine the 2008 SEC short selling ban on financial firms and whether this ban negatively impacted private information provision in these short‐restricted equities.

This paper employs the French and Roll Variance Ratio (VR) as a proxy for private information provision in both an unconditional and conditional analysis. The unconditional analysis examines the VR across trading characteristics, firm characteristics, and time regimes. The conditional analysis models the VR in an event study framework where exogenous determinants of private information provision are held constant.

Empirical results indicate that private information provision increased due to the 2007 US financial crisis while information provision decreased due to the 2008 short selling ban. This study concludes that the 2007 financial crisis enticed informed short sellers into the market which then increased information provision. Further, the 2008 short selling ban restricted these informed short sellers from the market thus leading to a decrease in information provision in the short‐restricted firms. Interestingly, the information restricting effects of the 2008 ban were not severe enough to erode the gains in information provision originally induced by the financial crisis.

This paper specifically contributes by demonstrating that the 2008 SEC short selling ban negatively impacted private information provision. This paper contributes generally by showing that short sale bans' information effects are not completely restrictive. Rather, short sale bans' information effects are a function of firm characteristics and contemporaneous market conditions.

The purpose of this paper is to investigate the effects of the 2008 SEC short‐sell moratorium on regional bank risk and return. The paper also examines the decline in “failures to deliver” securities in the wake of SEC short‐sell moratorium.

In total, six regional bank portfolios are derived and the beta coefficients from a CAPM model are estimated using the integrated generalized autoregressive conditional heteroskedasticity (IGARCH) method accounting for the short‐sell moratorium. Data on 110 regional banks in six US regions from January 2002 to December 30, 2011 are used to estimate the model.

The ban on naked short selling and the SEC short‐sell moratorium significantly increased individual bank risk for a majority of banks in six geographic regions, but also increased return in three of three regions. There was also reduced naked short selling as failures to deliver securities declined sharply after the September 2008 moratorium took effect.

Regional banks have generally not achieved the size needed to be deemed “too big to fail” by policy‐makers. Thus, policy changes such as the SEC short‐sell moratorium might be expected to have larger effects on regional banks than on larger banks, which might be shielded from the policy change by having achieved “too big to fail” status. The authors' results are consistent with research that has shown that short‐sell restrictions increase risk by reducing liquidity and trading volume.

The purpose of this paper is to empirically examine whether corporate insiders extract information from activity of outsiders, specifically the short sellers.

Using portfolio approach and Fama-MacBeth regressions, this study examines the relation between short interest and subsequent insider trading activities.

The following results are reported. First, there is a strong inverse relation between short selling and subsequent insider trading, which is partially due to common private information and same target firm characteristics. Second, insiders extract information from shorts. This information extraction effect is more pronounced for firms whose insiders have stronger incentives to extract shorts information (insider purchases, higher short sale constraints, and better information environments). Third, during the September 2008 shorting ban, the information extraction affect disappeared among the large banned firms, whose shorting activities were distorted.

The findings contradict the of-cited accusations corporate executives hold against short sellers. Instead, corporate insiders appear to trade in the same direction as suggested by shorting activities.

Among the vocal critics of short sellers are corporate insiders, who allege that short sellers beat down their stock prices. Many corporations even engage in stock repurchases to show confidence that the stock will perform well going forward despite the short sellers’ actions. This paper’s analysis on their personal portfolios suggests the other way around.

By focusing on how corporate insider trading is related to shorts information, this paper sheds new light on whether corporate decisions convey the true information the corporate insiders possess.

The paper aims to investigate the effectiveness of the ban on short trading of stocks on the London Stock Exchange, introduced in September 2008 in the immediate aftermath of the collapse of Lehman Brothers. In particular, the paper investigates how far the ban succeeded in achieving the objectives set out by the regulator, the Financial Services Authority (FSA).

The approach involves comparing the returns on a portfolio of stocks covered by the short-sales ban with a portfolio of financial stocks exempt from the ban as a control group.

The paper presents evidence to show the effects to the ban to have been mostly confined to a large first-day return. Beyond that, there is some evidence that volatility was diverted from stocks covered by the ban to those for which short-sales were still permitted. Investors seem to have been wary of buying banned stocks when good news arrived, presumably out of fear that they may be overpriced.

All event studies are subject to the curse of the counterfactual: what would have happened if the event had not occurred? The problem is especially acute here, however, because the background was the most turbulent in modern economic and financial history.

The paper shows the limited value of short-sales bans over anything beyond the very short-term.

This paper helps to inform regulatory decision-making in financial crises.

The purpose of this paper is to examine the efficacy of recent policy initiatives taken by the US Securities and Exchange Commission banning naked “short‐selling” of specific financial stocks. The paper also considers the merits of reinstating “uptick rule” 10a‐1, which prohibits short‐selling securities on a downtick.

The paper studies theoretical implications of short‐selling in a simple state‐claim model, reflecting varying amounts of short interest in a representative firm and noise trading in the market. Price discovery depends on the proportion of noise trading compared to rational short‐selling. The empirical analysis focuses on price volatility under short‐selling constraints employing simple regressions, EGARCH analysis and simulated price behavior under a hypothetical uptick rule.

The EGARCH results suggest short‐selling constraints had non‐uniform impacts on the persistence and leverage effects associated with price volatility. The corresponding price simulations indicate a hypothetical uptick rule might have helped stabilize price behavior in some cases, depending on the nature of the stochastic process and whether or not quantity constraints on short‐selling are binding.

The theoretical arguments and empirical findings suggest a “focused approach” to market regulation would be a more efficient means of discouraging trend chasing without compromising “informed trading” – that is to say, safeguarding price discovery and market liquidity without impeding arbitrage or confounding probability beliefs regarding firm survival. These conclusions are largely in accord with recent policy analysis and proposals outlined in Avgouleas.

The aim of this paper is to provide a review of the literature on short selling. In particular, it seeks to describe the history of short selling and anti-shorting laws. With respect to short-selling regulation, the main emphasis will be placed on the UK FSA’s regulatory action.

This paper reviews the history of short selling and the development of anti-shorting laws, particularly with regard to the UK market. It also analyses the distinct literature on short selling.

The paper argues that the development of anti-shorting laws shows that regulators are instituting a policy unfavourable to short sellers. The opposers of short selling may be seen as lacking ideas and having the tendency to ban anything they do not like. Short sellers, on the other hand, may be seen as the elite bodyguards of the financial market whose job is to get rid of overvalued stocks, and ultimately keep the market safe and efficient. For this reason, short sellers deserve our praise and thanks, not our hatred and opprobrium.

To the authors’ knowledge, this paper is the first to review the history of short selling and the development of anti-shorting laws, particularly with regard to the UK market.

The purpose of this paper is to take advantage of a natural experiment in Taiwan to test the effect of short‐sales constraints on price dynamics.

Since September 1998, short‐selling is banned at a price below the close price of the previous trading day. The new rule creates unique daily dynamics of short‐sales constraints. The paper employs a difference‐in‐difference method to evaluate whether the short‐sales constraint rule plays an important role in the price dynamics.

The results show that stock prices react to information in a way similar to if short‐selling was not banned. This is in line with the implication of a rational expectation framework like Diamond and Verrecchia.

The paper has implications on the short selling bans in the 2008/2009 credit crisis and the European debt crisis because the bans are public information as those in this setting. The rational agents in the market could incorporate the bans into price beliefs which could lead to the ineffectiveness of the policy. The short‐sales constraints may be widely imposed in the crisis but they are not the effective tools to alleviate downward price pressures.

The results suggest that the effort of the government to boost stock price by imposing short sales constraints will not be effective if rational investors take the constraints into account while forming their beliefs.

Unlike existing short‐sales constraint proxies like short interest or lending fees, the dynamic constraints do not suffer from endogeneity. Moreover, the constraints are public information and thus ideal for testing the rational expectation models, in which investors have to be aware of the level of the constraints.

The relationship between short selling, market volatility and liquidity remains an object of intensive research. However, empirical evidence is yet to provide a conclusive elucidation of this relationship by examining aspects of market fragmentation in the form of different market settings, different timing and different stocks under coverage, among others. This paper aims to contribute to the debate by investigating the impact of short selling on market volatility and liquidity in the Athens Exchange (ATHEX) under three different periods of short sales restrictions.

Two hypotheses are tested using econometric methodologies (co-integration and Granger-causality tools).

The empirical results indicate that when short selling is allowed, aggregate stock returns are in the short-term more volatile, but the liquidity of the market is not significantly affected. This might be the result of significant imbalances between supply and demand of stock caused by short-selling restrictions, leading to market price fluctuations.

The analysis of empirical evidence needs further expansion and association with institutional firm-level and country-level elements to provide a more comprehensive understanding of the impact of short selling on market volatility and liquidity.

Stock market regulation involving short-selling restrictions have different implications according to extent and degree of stringency of the restrictions as well as the market on which they are imposed. That is especially important for the assessment of the market impact of the recent European Union regulation on short selling that has been imposed upon all EU member-States alike.

Financial regulation policy must balance the benefits and costs for retail investors of imposing short-selling restrictions on stock market trading.

First-time empirical evidence is provided on the impact of short selling regulations on market volatility and liquidity of ATHEX highlighting the potential effectiveness of regulation policy.