Short selling around dividend announcements and ex-dividend days

We examine short selling around dividend announcements and ex-dividend dates. Contrary to our initial expectation, we do not find abnormally high short-selling activity prior to announced dividend decreases, which runs counter to the argument that short sellers have the ability to acquire private information before its public dissemination. However, we find that the common negative relation between current short selling and future daily returns prior to unfavorable dividend announcements is similar to the negative relation during non-event times, suggesting that dividend announcements do not provide unusual trading opportunities for informed traders (Gonedes, 1978, and Benartzi et al., 1997). Around ex-dividend dates, we do find abnormal short selling, which may be explained by the return pattern around ex-dividend days documented by Lakonishok and Vermaelen (1986), who suggest that demand for a particular stock by dividend capture traders drives stock prices above their fundamental value thus providing a profitable trading opportunity for short sellers. Consistent with this conjecture, we find that both the level of short selling and the return predictability of short selling is markedly higher on and after the ex-dividend day than during non-event times.     

Option trading: Information or differences of opinion?

This paper investigates the motive of option trading. We show that option trading is mostly driven by differences of opinion, a finding different from the current literature that attempts to attribute option trading to information asymmetry. Our conclusion is based on three pieces of empirical evidence. First, option trading around earnings announcements is speculative in nature and mostly dominated by small, retail investors. Second, around earnings announcements, the pre-announcement abnormal turnovers of options seem to predict the post-announcement abnormal stock returns. However, once we control for the pre-announcement stock returns, the predictability completely disappears, implying that option traders simply take cues from the stock market and turn around to speculate in the options market. Third, cross-section and time-series regressions reveal that option trading is also significantly explained by differences of opinion. While informed trading is present in stocks, it is not detected in options.     

Informed or speculative: Short selling analyst recommendations

Christophe et al. (2010) find evidence of abnormal short activity prior to analyst downgrades and argue that short sellers may be violating SEC insider-trading laws by trading on information obtained from analysts about upcoming downgrades. However, observing abnormal shorting prior to downgrades is not tantamount to determining that short sellers are trading on tips from analysts unless shorting is abnormally low prior to upgrades. This paper revisits this issue. While we observe abnormal shorting prior to downgrades, we also find markedly higher shorting prior to upgrades. In fact, the short-selling patterns surrounding both downgrades and upgrades are remarkably symmetric indicating that short sellers during the pre-recommendation period are not unusually informed about the direction of upcoming recommendation changes. If anything, our findings indicate that short selling prior to analyst recommendations is more likely speculative than informed.     

Trading volume and short-horizon contrarian profits: Evidence from the Malaysian market

We provide evidence on short-term predictability of stock returns on the Malaysian stock market. We examine the relation between return predictability and the level of trading activity. This is particularly relevant in emerging stock markets, where thin trading is more pervasive. We find that the returns from a contrarian portfolio strategy are positively related to the level of trading activity in the securities. Specifically, the contrarian profits on actively and frequently traded securities are significantly higher than that generated from the low trading activity securities. We find that the differential behavior of high- and low-volume securities is not subsumed by the size effect, although for the small firms, the volume–predictability relation is most pronounced. We also suggest that the price patterns may be related to the institutional arrangement in the Malaysian stock market.     

Intra–day Behavior of Treasury Sector Index Option Implied Volatilities around Macroeconomic Announcements

If option implied volatility is an unbiased, efficient forecast of future return volatility in the underlying asset, then we should be able to predict its path around macroeconomic announcements from responses in cash markets. Regressions show that volatilities rise the afternoon before announcements that move cash markets, and that post–announcement volatilities return to normal as rapidly as cash prices do. Although implied volatilities are predictable, the Treasury options market is efficient since informed traders do not earn arbitrage profits once we account for trading costs.     

Early Movers Advantage? Evidence from Short Selling during After‐Hours on Earnings Announcement Days

We examine short sellers’ after‐hours trading (AHT) following quarterly earnings announcements released outside of the normal trading hours. Our innovation is to use the actual short trades immediately after the announcements. We find that on these earnings announcement days, there is significant shorting activity in AHT relative to shorting activity both during AHT on nonannouncements days and during regular trading sessions around announcements. Short sellers who trade after‐hours on announcement days earn an excess return of 0.82% and 1.40% during before‐market‐open (BMO) and after‐market‐close (AMC)sessions, respectively. The magnitude of these returns increases to 1.48 (3.92%) for BMO (AMC) earnings announcements with negative surprise. We find that the reactive short selling during AHT has information in predicting future returns. Short sellers’ trades have no predictive power if they wait for the market to open to trade during regular hours. In addition, we find that the weighted price contribution during AHT increases with an increase in after‐hours short selling. Overall, our results suggest that short sellers in AHT are informed. Our findings remain robust using alternative holding periods and after controlling for macroeconomic news announcements during BMO sessions.     

A Characterization of the Daily and Intraday Behavior of Returns on Options

The daily and intraday behavior of returns on Chicago Board Options Exchange options is examined. Option returns contain systematic patterns even after adjusting for patterns in the means and variances of the underlying assets. This is consistent with the hypothesis that informed trading in options can make the order flow in the options market informative about the value of the underlying asset, making options nonredundant. The intraday patterns in adjusted option return variances are further consistent with a model of strategic trading by informed and discretionary liquidity traders.     

Comparing the information in short sales and put options

Prior work shows that both short sales and put options contain information about future stock prices. In this study, we compare the return predictability in short sales to the return predictability in put options. The motivation for this comparison is based on the theoretical argument that informed traders can choose between short sales and put options when establishing short positions in a particular stocks. Results in this paper suggest that the underperformance of stocks with high short-selling activity is approximately four times larger than the underperformance of stocks with high put-option activity. While stocks that are most likely to face binding short-sale constraints drive the underperformance caused by put-option activity, we still find that short sales are generally more informative about future prices.     

Trading activity and price reversals in futures markets

We use the standard contrarian portfolio approach to examine short-horizon return predictability in 24 US futures markets. We find strong evidence of weekly return reversals, similar to the findings from equity market studies. When interacting between past returns and lagged changes in trading activity (volume and/or open interest), we find that the profits to contrarian portfolio strategies are, on average, positively associated with lagged changes in trading volume, but negatively related to lagged changes in open interest. We also show that futures return predictability is more pronounced if interacting between past returns and lagged changes in both volume and open interest. Our results suggest that futures market overreaction exists, and both past prices and trading activity contain useful information about future market movements. These findings have implications for futures market efficiency and are useful for futures market participants, particularly commodity pool operators.     

Why do options prices predict stock returns? Evidence from analyst tipping

We study the role of analysts and options traders in the information transmission between options and stock markets. We first show that the predictive power of option implied volatilities (IVs) on stock returns more than doubles around analyst-related events, indicating that a significant proportion of the options predictability on stock returns comes from informed options traders’ information about upcoming analyst-related news. We examine three explanations for this finding: tipping, reverse tipping and common information. We find that analyst tipping to options traders is the most consistent explanation of these predictive patterns.     

Are margin traders informed?

The literature offers contradictory views on the informativeness of margin trading using various measures of information content. Utilising data from a Chinese margin‐trading pilot programme initiated in 2010, this paper investigates whether margin traders are informed by directly examining the return predictability of margin‐trading activity. We find that margin‐trading activities cannot positively predict future stock returns. Moreover, we explore some non‐informational trading strategies used by margin traders, e.g., positive‐feedback strategies and moving‐average trading rules. These results suggest that margin traders are noise traders rather than informed traders, and margin trading conveys no new firm‐specific information.     

Momentum,Reversal, and Uninformed Traders in Laboratory Markets

We report the results of three experiments based on the model of Hong and Stein (1999) . Consistent with the model, the results show that when informed traders do not observe prices, uninformed traders generate long‐term price reversals by engaging in momentum trade. However, when informed traders also observe prices, uninformed traders generate reversals by engaging in contrarian trading. The results suggest that a dominated information set is sufficient to account for the contrarian behavior observed among individual investors, and that uninformed traders may be responsible for long‐term price reversals but play little role in driving short‐term momentum.     

Short-selling,margin-trading,and stock liquidity: Evidence from the Chinese stock markets

This paper examines the impacts of two forms of leveraged trading—margin trading and short selling—on the trading liquidity of individual stocks in China. We find that trading liquidity for relevant stocks generally improves after restrictions on leveraged trading are removed. However, margin trading and short selling have opposite impacts on liquidity. During ordinary periods, margin trading benefits liquidity, whereas short selling damages liquidity; however, during market downturns, their roles are reversed. We also provide evidence suggesting that short sellers are informed traders in China and that short selling reduces stock liquidity because of the increased risk of adverse selection faced by uninformed traders.     

卖空限制与收益可预测性——A股融资融券制度的证据

基于A股市场融资和融券余额的巨大差距,本文拓展了Hong et al.(2016)的理论模型,在融券端和融资端分别找到了影响股票收益率的变量:融券比率(融券余额/流通市值)和融资回补天数(融资比率/日均换手率)。进一步,本文利用组合价差法和Fama-MacBeth横截面回归法,实证检验了A股市场中融券比率与融资回补天数解释和预测股票收益率的能力。实证结果表明,在存在融券限制条件下,融券比率相比融券回补天数(融券比率/日均换手率)能更好地代表套利者对股票价格高估程度的看法,根据融券比率构建的等权重多空组合能带来月均1.58%的显著收益;而由于融资约束相对较少,融资回补天数相比融资比率(融资余额/流通市值)能更好地代表套利者对股票价格低估程度的看法,根据融资回补天数构建的等权重多空组合能带来月均1.28%的显著收益。实证结果与本文存在融券数量限制下的理论模型相符,且该收益率不能被多因子模型和常规股票特征所解释。     

卖空者与内幕交易——来自中国证券市场的证据

本文研究上市公司内部人减持、年报、诉讼、分析师评级、停复牌以及高送转等重大公告前后卖空交易行为的变化,系统考察卖空者是否参与内幕交易以及何种因素影响卖空者参与内幕交易,发现卖空率较高的股票具有较低的未来收益,表明卖空者拥有信息优势,属知情交易者;卖空者拥有非常精确的择时交易能力,在重大利空公告前显著增加卖空量,而在利好公告前则显著减少卖空头寸,表明卖空者作为知情交易者的信息优势源自内幕消息;公司内、外部投资者的信息不对称程度越低或公司所在地的法治水平越高,卖空者参与内幕交易的行为就越少。因此,监管机构应密切关注公司重大消息发布前后卖空量的异常变动,同时,完善信息披露规则、健全证券分析师制度并强化法律法规的执行力度,才能有效防范卖空者参与内幕交易。     

The Allocation of Informed Trading Across Related Markets: An Analysis of the Impact of Changes in Equity-Option Margin Requirements

We examine the impact of changes in equity-option margin requirements on the liquidity of options and underlying stock markets. We find that the decrease in margin was associated with an increase in spreads and trade informativeness, and a decrease in depth for the underlying stocks. In contrast, option spreads decreased indicating a change in the relative allocation of informed traders between the two markets. When the required margin was increased, no significant change was observed in the underlying stocks, but option spreads increased. Overall, our results indicate that uninformed traders are more sensitive to the margin dimension of trading costs.     

卖空限制与收益可预测性——A股融资融券制度的证据

基于A股市场融资和融券余额的巨大差距,本文拓展了Hong et al.(2016)的理论模型,在融券端和融资端分别找到了影响股票收益率的变量:融券比率(融券余额/流通市值)和融资回补天数(融资比率/日均换手率)。进一步,本文利用组合价差法和Fama-MacBeth横截面回归法,实证检验了A股市场中融券比率与融资回补天数解释和预测股票收益率的能力。实证结果表明,在存在融券限制条件下,融券比率相比融券回补天数(融券比率/日均换手率)能更好地代表套利者对股票价格高估程度的看法,根据融券比率构建的等权重多空组合能带来月均1.58%的显著收益;而由于融资约束相对较少,融资回补天数相比融资比率(融资余额/流通市值)能更好地代表套利者对股票价格低估程度的看法,根据融资回补天数构建的等权重多空组合能带来月均1.28%的显著收益。实证结果与本文存在融券数量限制下的理论模型相符,且该收益率不能被多因子模型和常规股票特征所解释。     

Short sales and put options: Where is the bad news first traded?

Although the literature provides strong evidence supporting the presence of informed trading in both the option and the short equity markets, it is not clear which market attracts more informed trading. Using a unique dataset that covers intraday transaction data in the option and short equity markets, we investigate informed trading in a cross-market environment by explicitly studying the lead–lag relationship between the put net trade volume and short sales of the underlying stock. Our high frequency analysis shows that in general short sales contain more information. However, put options become more informative before the release of negative earnings announcements.     

Option trading after the opening bell and intraday stock return predictability

Prior literature finds that information is reflected in option markets before stock markets, but no study has explored whether option volume soon after market open has predictive power for intraday stock returns. Using novel intraday signed option-to-stock volume data, we find that a composite option trading score (OTS) in the first 30 min of market open predicts stock returns during the rest of the trading day. Such return predictability is greater for smaller stocks, stocks with higher idiosyncratic volatility, and stocks with higher bid–ask spreads relative to their options’ bid–ask spreads. Moreover, OTS is a significantly stronger predictor of intraday stock returns after overnight earnings announcements. The evidence suggests that option trading in the 30 min after the opening bell has predictive power for intraday stock returns.     

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.