Short-sale constraints and stock price informativeness

Morck, Yeung, and Yu (2000), in their pioneering study of international differences in stock price synchronicity, emphasize the effect of market development on investors' ability to incorporate firm-specific information into prices. We use a unique institutional feature in the Hong Kong market to investigate one of the important tools investors use to do this and hence reduce stock price synchronicity: short selling. Examining the cross-sectional and time-series variation in short-sale constraints in the Hong Kong market, we find that after the removal of short-sale constraints, stock prices become more informative and move less in tandem with the market.     

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 trading and short investing

Short selling is measured in the literature as both constraint (e.g., lending fees) and activity (e.g., trades). We show that these two measures capture separate effects, which we characterize into two different strategies. The first strategy, “short trading,” has minimal constraints, weekly scale return predictability and average risk. The second strategy, “short investing,” has high constraints, multi-month return predictability and higher risk. Moreover, each strategy incorporates different types of information. Short trading includes short-lived information while short investing includes more long-lived, fundamental information. This diversity in short sellers has implications for both theoretical and empirical research.     

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 selling constraints and politically motivated negative information suppression

This study examines the effect of short selling constraints on politically motivated suppression of negative information. We use a unique setting in China, in which there are multiple exogenous changes in short selling constraints and firms have strong incentives to suppress negative information during politically sensitive periods. Results from Difference-in-Differences analyses and a regression discontinuity design show that removing short selling constraints can reduce politically motivated bad news suppression. Short selling can reduce negative information suppression through the channels of improved financial reporting quality, more voluntary disclosure from management, and more timely release of information by media. In addition, the effect of short selling on reducing bad news hoarding is more pronounced for more politically sensitive meetings and for state-owned firms located in regions with weaker market and institutional development.     

Options,Short Sales,and Market Completeness

This paper presents empirical evidence that trading in options contributes to both transactional and informational efficiency of the stock market by reducing the effect of constraints on short sales. The significantly higher average level of short interest exhibited by optionable stocks supports the argument that options facilitate short selling. We also find significant effects on option prices, related to the short interest in the underlying stock. We then present evidence that options also increase information efficiency. Earlier work, that is replicated and extended here, has suggested that short sale constraints cause stock prices to underweight negative information. Options appear to reduce that effect.     

Worldwide short selling regulations and IPO underpricing

We study the impact of country-level short selling constraints on IPO underpricing. Examining 17,151 IPOs from 36 countries, we find that IPO underpricing tends to be greater in countries that ban short selling or security lending and in countries where short selling is not practiced. Non-positive first-day returns are more common in countries where short selling is allowed, security lending is allowed, and short selling is commonly practiced. Short selling constraints exacerbate the positive relation between investor sentiment and underpricing. Additional evidence suggests that higher quality information environments may partially alleviate the effects of short sale constraints on underpricing.     

Why do firm fundamentals predict returns? Evidence from short selling activity

This study uses short selling activity to test whether the relation between fundamentals and future returns is due to rational pricing or mispricing. We find that short sellers target firms with fundamental performance below market expectations. We also show that short selling activity reduces the return predictability of fundamentals by speeding up the price adjustments to negative fundamental signals. To further investigate whether the returns earned by short sellers reflect rational risk premia or mispricing, we exploit a natural experiment, namely Regulation of SHO, which creates exogenous shocks to short selling by temporarily relaxing short-sale constraints. Evidence from the experiment confirms that the superior returns to short sellers result from exploiting overpricing. Overall, our study suggests that the return predictability of fundamentals reflects mispricing rather than rational risk premia.     

Empirical Analysis of the Yield Curve: The Information in the Data Viewed through the Window of Cox, Ingersoll, and Ross

This paper uses recent advances in Bayesian estimation methods to exploit fully and efficiently the time-series and cross-sectional empirical restrictions of the Cox, Ingersoll, and Ross model of the term structure. We examine the extent to which the cross-sectional data (five different instruments) provide information about the model. We find that the time-series restrictions of the two-factor model are generally consistent with the data. However, the model's cross-sectional restrictions are not. We show that adding a third factor produces a significant statistical improvement, but causes the average time-series fit to the yields themselves to deteriorate.     

The impact of short-selling pressure on corporate employee relations

We show that randomly-selected Regulation SHO pilot firms respond to an increased threat of short selling by significantly improving their employee relations. Pilot firms enhance employee security to reduce the likelihood of employee-related negative publicity. The reduction of workplace concerns is most evident among pilot firms with higher degree of earnings manipulation, short interest potential, likelihood of labor disputes and employee whistle-blowing. Pilot firms experience better stock performance during the post Reg-SHO period after easing workplace concerns. Overall, our study provides novel evidence that the removal of short-selling constraints has a real effect on labor relations.     

Accruals quality,stock returns and asset pricing: Evidence from the UK

The extent to which accruals quality (AQ) is relevant for asset pricing has been debated widely. Prior research in this area has focused almost exclusively on the US. Using UK data, we investigate whether AQ portfolios exhibit evidence of significant mispricing, and whether an AQ factor is useful in explaining the portfolios' returns. We also investigate whether AQ is a priced risk factor. Using a two stage cross-sectional regression, we show that an AQ measure explains the cross-section of stock returns. AQ also explains the time-series variation in returns for two sets of portfolios: 16 size-BM portfolios, and 20 industry portfolios. Consistent with some recent US evidence, however, we find no evidence that AQ is a priced risk factor for UK stocks.     

卖空威胁、公司融资扩张战略与违规行为

利用中国推出融资融券业务的准自然实验机会,本文以2010—2016年中国A股上市公司为样本,使用双重差分模型研究放松卖空限制对企业违规行为的影响。研究发现,融券业务允许市场中的知情投资者挖掘企业负面信息进行卖空,形成有效的卖空威胁,从而震慑企业,显著降低其发生违规行为的概率。具体而言,卖空交易行为跟企业违规行为的严重程度正相关;卖空交易行为能显著降低企业的超额收益率;当企业有进一步融资需求或并购扩张战略需求时,卖空威胁对企业的震慑作用更为显著。研究表明,融券业务带来的卖空威胁是企业外部监管的重要机制。     

Detecting earnings management using cross-sectional abnormal accruals models

This paper examines specification and power issues in relation to three models used to estimate abnormal accruals. In contrast to the majority of prior work evaluating models estimated in time-series, we examine the performance of cross-sectionally estimated models. In addition to testing the standard-Jones (Jones, 1991) and modified-Jones (Dechow et al., 1995) models, we also develop and test a new specification, labelled the ‘margin model’. Consistent with prior US research employing time-series specifications of the two Jones models, our findings suggest that each of the three cross-sectional models are well specified when applied to a random sample of firm-years. However, the margin model appears to generate relatively better specified estimates of abnormal accruals when cash flow performance is extreme. Analysis of the models' ability to detect artificially induced earnings management indicates that all three procedures are capable of generating relatively powerful tests for economically plausible levels of accruals management (e.g., less than 10% of lagged total assets). Regarding their relative performance, the standard-Jones and modified-Jones models are found to be more powerful for revenue and bad debt manipulations. In contrast, the margin appears to be more powerful at detecting non-bad debt expense manipulations.     

REGULATORY INFLUENCES ON PORTFOLIO PERFORMANCE: SHORT SELLING AND REGULATION T

Several models are developed to examine the portfolio effect of short selling. Three things are demonstrated in this study. First, that for many assets, short selling is a useful strategy for reducing risk when constructing mean-variance efficient portfolios. Second, Regulation T can be used in combination with short selling to further improve expected portfolio performance. Third, the performance of the suggested models is superior to previously suggested allocation models. Ex ante and ex post tests are conducted to arrive at the above conclusions.     

Security price formation and informed trading with constrained short selling

Short sale orders account for a substantial portion of trading volume in recent years. This paper develops a sequential trade model with constrained short selling to derive the effect on prices when the market maker can observe short selling in the order flow. The model predicts that market quotes will adjust differently to short sales and regular sales. Furthermore, the model shows that the probability of informed trading is impacted both by the level of short sale constraints and the intensity of actual short sale trades. Simulation evidence confirms that estimates of the probability of informed trade are improved when accounting for past short selling activity. The results demonstrate the information benefits of short selling transparency.

     

Informed short sales and option introductions

This study examines how the introduction of options affects the level of informed short selling. In particular, we test whether option introductions increases or decreases the level of informed short selling. Our tests are motivated by a theoretical debate in the literature. The first stream of literature argues that introducing options into markets may increase speculative trading which can result in less informed trading when informed traders perceive speculative trades as noise. The second stream argues that introducing options into markets improves the informational environment of the market because option prices provide an additional information mechanism for informed traders. We approximate informed short selling by examining (i) non-exempt short sales, (ii) contrarian short-selling activity, and (iii) the return predictability contained in shorting activity. Results show that non-exempt shorting activity increases after options become available. Further, we show that both the level of contrarian short selling and the return predictability contained in short selling increase after options are listed. Our results suggest that informed short selling increases after options are introduced.     

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.     

Identifying Term Structure Volatility from the LIBOR-Swap Curve

This paper proposes a new family of specification tests andapplies them to affine term structure models of the London InterbankOffered Rate (LIBOR)-swap curve. Contrary to Dai and Singleton(2000), the tests show that when standard estimation techniquesare used, affine models do a poor job of forecasting volatilityat the short end of the term structure. Improving the volatilityforecast does not require different models; rather, it requiresa different estimation technique. The paper distinguishes betweentwo econometric procedures for identifying volatility. The "cross-sectional"approach backs out volatility from a cross section of bond yields,and the "time-series" approach imputes volatility from time-seriesvariation in yields. For an affine model, the volatility impliedby the time-series procedure passes the specification tests,while the cross-sectionally identified volatility does not.This is surprising, since under correct specification, the "cross-sectional"approach is maximum likelihood. One explanation is that affinemodels are slightly misspecified; another is that bond yieldsdo not span volatility, as in Collin-Dufresne and Goldstein(2002).     

Short selling of ADRs and foreign market short-sale constraints

We examine the effect of home market short-sale constraints on securities that also trade in other countries that have more liberal short-sale rules. In particular, we focus on the case of ADRs traded in the US, as in some cases, the home markets of these ADRs prohibit short selling. We find that short sellers more heavily trade ADRs from countries where short selling is prohibited than from markets where short selling is allowed. Furthermore, we find that the greater levels of short selling in ADRs with binding home-market constraints is driven by stocks with greater dispersion of investors’ opinion, low fundamentals-to-price ratios, and recent price increases. Our results support the hypothesis that short sellers target ADRs with home market short-sale constraints because these ADRs are more often subject to temporary misvaluation.     

Limited arbitrage and short sales restrictions: evidence from the options markets

We investigate empirically the well-known put–call parity no-arbitrage relation in the presence of short sales restrictions. Violations of put–call parity are asymmetric in the direction of short sales constraints, and their magnitudes are strongly related to the cost and difficulty of short selling. These violations are also related to both the maturity of the option and the level of valuations in the stock market, consistent with a behavioral finance theory of over-optimistic stock investors and market segmentation. Moreover, both the size of put–call parity violations and the cost of short selling are significant predictors of future returns for individual stocks.