Against the tide: the commencement of short selling and margin trading in mainland China

China's recent removal of short‐selling and margin trading bans on selected stocks enables testing of the relative effect of margin trading and short selling. We find the prices of the shortable stocks decrease, on average, relative to peer A‐shares and cross‐listed H‐shares, suggesting that short selling dominates margin trading effects. Contrary to the regulators' intention and recent developed market empirical evidence, liquidity declines and bid‐ask spreads increase in these shortable stocks. Consistent with Ausubel (1990), these results imply that uninformed investors avoid the shortable stocks to reduce the risk of trading with informed investors.     

Impact of short selling activity on market dynamics: Evidence from an emerging market

With unique daily short sale data of Borsa Istanbul (stock exchange of Turkey), we investigate the dynamic relationship between short selling activity and volatility, liquidity and market return from January 2005 to December 2012 using a VAR(p)-cDCC-FIEGARCH(1,d,1) approach. Our findings suggest that short sellers are contrarian traders and contribute to efficient stock market in Turkey. We also show that increased short selling activity is associated with higher liquidity and decreased volatility. However this relation weakens during the financial turmoil of 2008. Our results indicate that any ban on short sales may be detrimental for financial stability and market quality in Turkey.     

Which financial stocks did short sellers target in the subprime crisis?

Tracing the SEC ban on the short selling of financial stocks in September 2008, this paper investigates whether such selling activity before the 2008 short ban reflected financial companies’ risk exposure in the subprime crisis. Evidence suggests that short sellers sold short stocks that had the greatest asset and insolvency risk exposures, and that the short selling of financial firms’ stocks was not significantly greater than that of non-financial firms after we match them on firm size and insolvency risk. When the short ban was in effect, the market quality of financial stocks without subprime assets exposure had deteriorated to a larger degree than that of financial companies with subprime assets exposure. The findings imply that such a regulation may mute the market disciplining effects of investors and may also be seen as a counterweight to any perceived macro or systemic risk reduction benefits resulting from such a ban.     

The determinants of short selling: evidence from the Hong Kong equity market

While most financial regulators agree that short sellers have an important role to play in ensuring an efficiently functioning market, it is interesting to note that many did not hesitate to ban short selling during the recent financial crisis. This apparent contradiction most likely stems from a lack of understanding about what motivates short trading. In this paper, we focus on the determinants of short selling during ‘normal’ trading in the Hong Kong stock market. We find that dividend payments, company fundamentals, risk, option trading, the interest rate spread and past returns and short selling are all significant determinants of short selling.     

The 2011 European short sale ban: A cure or a curse?

This paper examines whether the 2011 European short sale ban on financial stocks proved to be successful or had a negative impact on financial markets. We explicitly take an options market perspective and focus on market participants’ changes in beliefs and expectations. During the ban, short positions in banned stocks decreased, whereas they increased for non-banned stocks. Our results indicate that the ban increased implied jump risk levels, thereby negatively impacting the banned financial stocks. However, we also observe that after the announcement of the ban, financial contagion risk actually dropped for banned stocks. Instead of a substitution effect between regular short selling and synthetic shorting through single stock puts, we observe a migration out of single stock puts into the EuroStoxx 50 index options market. We conclude that this type of migration diversified selling pressure initially concentrated in financial stocks across a larger share of the stock market, thereby reducing systemic risks and enhancing overall financial stability.     

Can Short Restrictions Actually Increase Informed Short Selling?

We use the 2008 short selling regulations to test whether short sale restrictions can increase informed short selling. For the preborrow requirement, we find more negative price reactions to short interest announcements though no reliable increase in the price impact of short sales volume. For the stocks with banned short sales, we find an increase in the price impact of short sale volume though no reliable change in the price reaction to short interest announcements. Both restrictions, however, are associated with increased informed trading. Our results suggest that short restrictions will not reduce informed short selling and may actually result in an increase by increasing the proportion of informed short sellers..     

Worldwide reach of short selling regulations

We characterize legality and incidence of short selling in a worldwide, multimarket framework. Home country short selling restrictions curtail home market stock borrowing by 45% and reduce short selling of the country's American Depository Receipts (ADRs) by 68% due to regulatory reach. Also, the 2008 US ban on short selling of financial firms reduced borrowing in foreign locations. These findings are robust to controls for option availability, enforcement, returns, firm size, trading volume, dividends, ADR level, volatility, days-to-cover, and industry sector. Further, we show that investor conduct resulting from adherence to professional standards is a more powerful mechanism of regulatory reach than intergovernment cooperation.     

Regulatory Uncertainty and Market Liquidity: The 2008 Short Sale Ban's Impact on Equity Option Markets

We examine how the September 2008 short sale restrictions and the accompanying confusion and regulatory uncertainty impacted equity option markets. We find that the short sale ban is associated with dramatically increased bid‐ask spreads for options on banned stocks. In addition, synthetic share prices for banned stocks become significantly lower than actual share prices during the ban. We find similar results for synthetic share prices of hard‐to‐borrow stocks, suggesting that the dislocation in actual and synthetic share prices is attributable to the increased hedging costs for options on banned stocks during the short sale ban.     

The skinny on the 2008 naked short-sale restrictions

On July 15, 2008, the US Securities and Exchange Commission announced temporary restrictions on naked short sales of the stocks of 19 financial firms. The restrictions offer a unique empirical setting to test Miller’s (1977) conjecture that short-sale constraints result in overpriced securities and low subsequent returns. Consistent with Miller’s overpricing hypothesis, we find evidence of a positive (negative) market reaction to the announcement (expiration) of the short-sale restrictions. Announcement returns are higher for firms that appear to be subject to more naked short selling in the days immediately preceding the announcement of the restrictions. The restrictions are successful in eliminating naked short sales for the restricted stocks, but naked short sales increase dramatically for a closely matched sample of financial firms during the restricted period. We also find that the restrictions negatively impact various measures of liquidity, including bid-ask spreads and trading volume. From a public policy perspective, our findings suggest that, at a minimum, policymakers should pause when considering further short sale restrictions.     

Banning short sales and market quality: The UK’s experience

We study the effects that the ban on short sales of shares in financial firms introduced in late 2008 and removed early 2009 had on the microstructure and the quality of UK equity markets. We show that the ban did nothing to affect order flows: financial stocks were being more aggressively sold off than their peers pre-ban and this situation persisted through the ban period. Trading volume in financials was massively reduced, however. The ban decimated order book liquidity for financials. The deterioration was symmetric, affecting the limit buy and limit sell side of the order book equally. Finally we show that, through the period of the ban, markets for financial stocks were substantially less efficient and that the role of the trading process in aiding price discovery was greatly reduced. The effects identified above were largely reversed once the ban was lifted. The persistence of the deterioration in market quality and liquidity though the relatively long-lasting UK ban on short selling suggests that other major market developments such as the TARP program were not responsible since these were concentrated in the early half of the ban. We thus argue that the short selling ban was responsible for detrimental effects on the quality of UK equity markets and that, far from being stabilising, the ban exacerbated problems in valuing UK financial stocks.     

Sovereign CDS Spreads,Volatility, and Liquidity: Evidence from 2010 German Short Sale Ban

The paper examines global impact of 2010 German short sale ban on sovereign credit default swap (CDS) spreads, volatility, and liquidity across 54 countries. We find that CDS spreads continue rising after the ban in the debt crisis region, which suggests that the short selling ban is incapable of suppressing soaring borrowing costs in these countries. However, we find that the ban helps stabilize the CDS market by reducing CDS volatility. The reduction in CDS volatility is greater in the eurozone than that in the non‐eurozone. Furthermore, we find that the CDS market liquidity has been impaired during the ban for the PIIGS (Portugal, Ireland, Italy, Greece, and Spain) countries. In contrast, there are no dramatic changes in the market liquidity for non‐PIIGS eurozone and non‐eurozone samples. The findings suggest that the short sale ban is ineffective to reduce sovereign borrowing costs in the debt crisis region if the underlying economy has not been significantly improved.     

Banks, Bears, and the Financial Crisis

We test whether short selling is destabilizing comparing distressed financial firms to other firms using NYSE transactions records covering 4 years including the recent financial crisis. Aggressive short-selling is sometimes destabilizing by some measures, but its impact is small, vanishes quickly, is not necessarily larger for distressed firms or during the crisis, and is accompanied by other stabilizing effects. The evidence does not validate theoretical predictions from models of destabilizing speculative or predatory trading. Aggregate short-selling is largely unrelated to market-wide investor sentiment, credit risk, and ex ante volatility. Aggressive liquidation of long positions typically has more impact than short selling. Thus, the data cannot justify the restrictions on short sales of financial stocks imposed in September 2008.     

Are short sellers positive feedback traders? Evidence from the global financial crisis

Short sellers are routinely blamed for destabilizing stock markets by exacerbating deviations from fundamental values. In response, regulators periodically impose short sale constraints aimed at preventing excessive stock market declines. One explanation is that policy makers regard short sellers as behaving like positive feedback traders. Relying on the theoretical model put forward by Sentana and Wadhwani (1992), which stresses the conditional nature of returns’ persistence, bans on selected financial stocks in six countries during the 2008/2009 global financial crisis are examined. These provide us with a setting to analyze the impact of short sale restrictions on feedback trading. Our findings suggest that, in the majority of markets examined, restrictions of this kind amplify positive feedback trading during periods of high volatility and, hence, contribute to stock market downturns. On balance then, short selling bans do not contribute to enhancing financial stability.     

The costs and benefits of short sale disclosure

In this study, we examine the impact of a market-wide mandatory disclosure policy on short selling on the Tokyo Stock Exchange. We find that average short selling slightly declined while investors’ shorting strategies changed significantly in response to the disclosure. Previously highly shorted stocks were shorted less and shorting activity shifted toward smaller and riskier stocks, suggesting that retail investors became the more likely short sellers. Short sales became more trend-chasing, prices became less informative, and short-term price volatility increased. Overall, the pricing efficiency benefits of short selling declined after the mandatory disclosure policy.     

Short-selling restrictions and firms’ environment responsibility

We examine the effect of short selling on firms’ environmental pollution control behavior. Using novel data from Chinese listed firms, we demonstrate that when the short selling of stocks is permitted, the respective firms invest more in pollution protection. Consequently, ex ante threats to short selling could potentially explain firms’ investment in pollution protection. In contrast, we do not find a positive relation between margin trading and firms’ pollution protection expenses. We further discover that the effect of short selling is more pronounced in firms with lower institutional ownership and lower market competition. These findings shed light on the role of short sales in pollution abatement.     

Margin trading,short selling,and bond yield spread

Using a quasi-natural experiment, this study examines the effects of margin trading and short selling on bond yield spread in China. It finds that both margin trading and short selling can reduce bond yield spread. Additionally, it finds that margin trading lowers firms’ debt ratios and increases their credit ratings, which explains the reduced spread. In other words, margin trading can impact investors’ decisions by revealing positive information about a firm. Another finding is that short selling lowers the bond yield spread by decreasing earnings management, suggesting that short selling has an impact on investors’ decisions through its effect on corporate governance. Our results suggest that margin trading transmits positive information and short selling impacts firms’ policies. These results provide support for future regulations of margin trading and short selling.     

Distribution of Ownership,Short Sale Constraints,and Market Efficiency: Evidence from Cross‐Listed Stocks

We investigate the interplay between the distribution of ownership, short sale constraints, and market efficiency. Using minute‐by‐minute data during the period surrounding the short sale ban of 2008, we demonstrate that short sale restrictions cause price disparities among cross‐listed stocks when ownership in the stocks is distributed unevenly across the two markets. The stocks tend to trade at a premium in the market where long sellers are relatively scarcer, which reduces the speed at which prices adjust to bad news. The premium is driven primarily by an increase on the ask side of the market where ownership is thinner, is only evident when prices are moving down, and disappears quickly.     

Capitalizing on Catastrophe: Short Selling Insurance Stocks Around Hurricanes Katrina and Rita

We develop several hypotheses regarding short‐selling activity around Hurricanes Katrina and Rita. We find that abnormal short selling does not increase until 2 trading days after the landfall of Katrina and that short‐selling activity is much more significant around Rita. We find a substantial increase in short‐selling activity in the trading days prior to the landfall of Rita and relatively less short‐selling activity in the trading days after landfall. There is little evidence that suggests that traders short insurance stocks with more potential exposure in the Gulf region than other insurance stocks in the days before landfall.     

Can short selling improve internal control? An empirical study based on the difference‐in‐differences model

Based on pilot margin trading in China, this study examines how short selling affects internal control quality in listed firms. Using the difference‐in‐differences approach, we find that compared with control firms, firms that are eligible for short selling significantly improve their internal control after they are designated as underlying securities. We consider the effects of state ownership and external auditors. The improvement in internal control is only significant for non‐state‐owned firms and firms audited by non‐Big 4 auditors. These findings indicate that short selling can improve firms’ internal control and play a role in their corporate governance.     

DotCom Mania: The Rise and Fall of Internet Stock Prices

This paper explores a model based on agents with heterogenous beliefs facing short sales restrictions, and its explanation for the rise, persistence, and eventual fall of Internet stock prices. First, we document substantial short sale restrictions for Internet stocks. Second, using data on Internet holdings and block trades, we show a link between heterogeneity and price effects for Internet stocks. Third, arguing that lockup expirations are a loosening of the short sale constraint, we document average, long‐run excess returns as low as ?33 percent for Internet stocks postlockup. We link the Internet bubble burst to the unprecedented level of lockup expirations and insider selling.