Short Selling and the Weekend Effect in Nasdaq Stock Returns

We examine daily short selling of Nasdaq stocks to explore whether speculative short selling causes a significant portion of the weekend effect in returns. We identify a weekend effect in speculative short selling whereby it constitutes a larger percentage of trading volume on Mondays versus Fridays. We find an opposite effect in dealer short selling, consistent with market makers adding liquidity and stability. Our main finding is that speculative short selling does not explain an economically meaningful portion of the weekend effect in returns, even among the firms most that are most actively shorted. This finding contradicts some prior studies.     

Short Selling and the Weekend Effect for NYSE Securities

Using short-sale transactions data, we examine the relation between short selling and the weekend effect. We do not find that short selling is more abundant on Monday than on Friday, even for stocks that have higher Friday returns. We find that short sellers execute more short-sale volume during the middle of the week, and that the positive correlation between short selling and returns on Monday is greater, on average, than the correlation on the other days of the week. Our results are robust to subsamples of stocks with larger weekend effects and stocks that do not have listed options.     

Weekday variations in short-term contrarian profits in futures markets

This article documents and examines weekday patterns in short-term contrarian profits in futures markets. The Lo and Mackinlay (1990) methodology is used to construct contrarian portfolios and to compute daily contrarian profits. Contrarian portfolios are formed using daily closing prices and are based on the previous day's performance relative to a benchmark. Contrarian profits are measured over subsequent half-day intervals. The empirical results suggest that there are weekday patterns in short-term contrarian profits in futures markets. On average, contrarian profits are largest on Fridays, followed by those on Wednesdays, and smallest on Mondays. For currency futures, however, contrarian profits are largest on Mondays and smallest on Fridays.     

Which Shorts Are Informed?

We construct a long daily panel of short sales using proprietary NYSE order data. From 2000 to 2004, shorting accounts for more than 12.9% of NYSE volume, suggesting that shorting constraints are not widespread. As a group, these short sellers are well informed. Heavily shorted stocks underperform lightly shorted stocks by a risk‐adjusted average of 1.16% over the following 20 trading days (15.6% annualized). Institutional nonprogram short sales are the most informative; stocks heavily shorted by institutions underperform by 1.43% the next month (19.6% annualized). The results indicate that, on average, short sellers are important contributors to efficient stock prices.     

Trading Returns for the Weekend Effect Using Intraday Data

The existence of the weekend effect has been documented as early as 1885. This paper examines whether the serial dependence in returns around weekends and the magnitude of negative Friday returns can be used to produce superior trading returns. We find some success for this endeavor after accounting for transaction costs (including the bid/ask spread), especially when trading is confined to weekends for which there are large negative Friday returns and to positions opened on Friday afternoons. The effect of stocks trading ex-dividend on Mondays does not appear to bias our results.     

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.     

Daily short interest,idiosyncratic risk,and stock returns

This paper examines the relation between short selling and returns and the impact of arbitrage costs on short sellers’ behavior. Using daily UK short selling data, we find that stocks with low short interest levels experience significant positive returns on both an equal- and value-weighted basis. Economic theory predicts that short sellers avoid establishing positions in stocks with high idiosyncratic risk. Our results indicate a negative relation between short interest and returns among high idiosyncratic risk stocks and that short selling activity is mostly concentrated in low idiosyncratic risk stocks where it is less costly to arbitrage fundamental risk.     

Price discovery in the CDS market: the informational role of equity short interest

This paper documents a negative relation between equity short interest and future returns on credit default swaps (CDS). This relation is most consistent with the theory that equity short interest telegraphs relevant information to secondary market CDS investors about credit spread not transmitted into prices in other ways. The CDS return predictive pattern also strengthens negatively for equity short-interest positions subject to an outward shift in the demand for shortable stocks, which we view as a proxy for the expected benefits of private information (Cohen et al. in J Finance 62(5):2061–2096, 2007). This suggests that features of the shorting market may help explain the lagged response of CDS spreads to equity short interest. Our tests of economic significance, however, do not support the view that the CDS return predictive pattern is strong enough to cover the round-trip cost of trading in the secondary CDS market.     

Short Selling and Intraday Price Pressures

We study episodes of significant intraday downward price pressures in individual stocks and find that price declines during such episodes are driven mainly by liquidity demanding nonshort volume. Although short sellers during these price pressure episodes are also active and somewhat exacerbate the magnitude of price declines, their influence on prices is secondary to that of nonshort sellers. As such, our findings are inconsistent with the recently reignited allegations of systematic trading abuses caused solely by short sellers and might shed light on the debate regarding the need to reinstitute short selling restrictions.     

Unpredicted costly dividends and temporary short squeezes

We argue that cash dividend is a type of arbitraging cost that short sellers tend to avoid. We find that dividend announcements lead to temporary short squeezes, causing the prices of highly shorted stocks to overshoot and fully revert over time. These stocks also experience excessive buy-initiated trades and abnormal trading volume in response to dividend announcements. These results are driven mainly by stocks with unpredicted dividends, low lending fees, and high dividend yields. Overall, results suggest that news of a dividend distribution is magnified by short squeezes due to increased short costs and generates excessive nonfundamentals-driven price fluctuations.     

Are Short Sellers Informed? Evidence from the 2007–2008 Subprime Mortgage Crisis

This paper examines the short selling activities around financial firms’ announcements of asset write‐downs during the 2007–2008 subprime mortgage crisis. We find that short sellers accumulate short positions prior to write‐down announcements, and that stocks experience significantly negative returns around such announcements. These results suggest that the return predictability of short interests is due to short sellers’ informational advantage. Furthermore, we show that short sellers increase their positions significantly in the announcement month and keep increasing their positions afterward, suggesting the feedback effect of the disclosed write‐downs on financial firms’ existing exposures. The valuable information contained in the short interest should encourage regulators to mandate stock exchanges disclose short selling activities more frequently.     

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 Interest and Frictions in the Flow of Information

This paper examines the correlation between short interest and price delay that parsimoniously measures the delay with which stock prices incorporate information. I find that price delay relates inversely to short interest indicating that short sellers reduce friction in the flow of information into stock prices. While price delay is shown to predict positive returns, this is mostly true in stocks with the least amount of short interest. Multivariate tests determine that the positive relationship between delay and future returns is decreasing in short interest. Results suggest that short sellers reduce delay and arbitrage the return premium commanded by delay.     

Flying under the radar: The effects of short-sale disclosure rules on investor behavior and stock prices

We study how disclosure requirements for large short positions affect investor behavior and security prices. Short positions accumulate just below the applicable disclosure threshold as certain investors never disclose any of their positions. Further tests suggest that this secrecy is part of investors’ general policy of avoiding disclosure to protect their unique, profitable investment strategies against reverse engineering by competitors. No evidence supports the notion that short sellers avoid disclosure because of potential adverse effects on securities' lending fees, risk of recall, or short squeezes. Finally, the evasive behavior by short sellers in response to transparency regulations hampers price discovery.     

Short‐Selling Risk

Short sellers face unique risks, such as the risk that stock loans become expensive and the risk that stock loans are recalled. We show that short‐selling risk affects prices among the cross‐section of stocks. Stocks with more short‐selling risk have lower returns, less price efficiency, and less short selling.     

Retail investor information demand – speculating and investing in structured products

We study the impact of retail investor information demand on trading in bank-issued investment and leverage structured products, which are specifically designed for retail investors. Stock-specific information demand positively predicts speculative trading activity. Furthermore, we find a positive relationship between market-wide information demand and order aggressiveness and order uncertainty for speculating and investing activity. Whereas information supply is associated with speculative long positions, information demand does not induce investors to be predominantly long or short. Finally, we do not find retail investor information demand to contribute to an upward price pressure on security prices. In contrast, information supply exerts negative price pressure. Overall, retail investor trading in individual stocks is much more strongly influenced by market-wide information demand instead of firm-specific information demand. This implies a low informational efficiency of retail investor speculation and investing activity.     

The puzzling behavior of short sellers around earnings announcements

We examine the performance of ‘predictive’ and ‘reactive’ short sellers who take relatively large short positions immediately before and after quarterly earnings announcements, respectively. While both types short into advancing markets, it is surprising for reactive shorts since their trades are in stocks that just announced unexpected good news and thus, according to the post-earnings announcement drift anomaly, will subsequently have abnormally high cumulative returns. Nevertheless, we find that for both types of short sellers: (1) subsequent cumulative returns are significantly negatively related to the amount of abnormal short selling, suggesting they are informed, and (2) relative to non-earnings dates, the subsequent returns around earnings announcements are significantly more negative, indicating they appear to be adept at exploiting earnings announcements. Surprisingly, we find that the subsequent returns of reactive short sellers are significantly greater than those of predictive short sellers except for S&P 500 stocks, perhaps due to their greater analyst following. Importantly, we are left with two puzzles. First, reactive shorts would have significantly improved their performance had they based their trades on the size of standardized unexpected earnings (‘SUE’). Second, predictive shorts of Micro stocks would have significantly improved their performance had they simply waited until earnings were announced and then based their trades on SUE.     

The Distribution of Foreign Exchange Price Changes: Trading Day Effects and Risk Measurement

This study investigates the nature of price changes in a variety of major and minor foreign exchange markets. The results suggest that the log of price changes over one (trading) day intervals seems to follow a non-normal stable distribution function. Different measures of location (and to lesser extent scale) are present for different days of the week. Dollar denominated price changes are high on Mondays and Wednesdays and low on Thursdays and Fridays for all currencies. The Wednesday-Thursday result is consistent with the settlement procedures used in foreign exchange transactions in the dollar. The Friday-Monday result is consistent with an increase in demand for the dollar prior to the weekend.     

Short selling activity,price efficiency and fundamental value of IPO stocks

In this study, we take advantage of the unique features of the Taiwan stock market, where short selling is forbidden within the first six months following an IPO. We examine the effects of short selling on IPO price efficiency and the relation between short selling activities and the fundamental value of IPO stocks. We find that price efficiency is improved with increased short selling after the lifting of short sale constraints on IPO stocks. We also show that short sellers tend to target IPO stocks with low fundamental ratios, but simultaneously avoid stocks with high transaction costs. In addition, we provide empirical evidence that short sellers focus more on temporary price fluctuations rather than temporary fluctuations in fundamentals.     

Do arbitrageurs amplify economic shocks?

We test the hypothesis that arbitrageurs amplify economic shocks in equity markets. The ability of speculators to hold short positions depends on asset values. Shorts are often reduced following good news about a stock. Therefore, the prices of highly shorted stocks are excessively sensitive to shocks compared with stocks with little short interest. We confirm this hypothesis using several empirical strategies including two quasi-experiments. In particular, we establish that the price of highly shorted stocks overshoots after good earnings news due to short covering compared with other stocks.