Short Selling and Efficient Sets

The effect of short selling on the composition and location of the efficient set has been analyzed in a variety of ways. However, the situation typically facing investors where the initial margin requirement is less than 100 percent and the riskfree interest rate that is paid on the short proceeds is less than the rate paid on initial margin has not previously been considered. The Elton-Gruber-Padberg algorithm (1976, 1978), subject to certain modifications, is shown here to be capable of identifying the efficient set under such conditions.     

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 Behavior and Mad Money

We examine 1,234 buy recommendations from Jim Cramer's Mad Money television show. Consistent with prior research, we report positive abnormal returns immediately after buy recommendations, followed by a reversal, indicative of an overpricing event. We also find a marked increase in short selling. Our results show a positive association between shorting and the buy recommendations even after controlling for factors shown in the literature to influence shorting. We do not find similar effects after sell recommendations. These results suggest that short sellers act to exploit short‐term overpricing arising from behavioral biases of some investors.     

Short Selling and Firm Operating Performance

While it is well known that short selling predicts future negative stock price performance, it has not been established whether short selling predicts future negative operating performance. We find that firms in the top decile of increases in short interest (an increase of about four percentage points) experience a 21% subsequent decline in operating performance relative to matched control firms. The greater the increase in short interest, the larger the decline in operating performance. The results are robust to alternative performance measures and to sample splits based on firm size. These results suggest that short interest may reflect private information about firm fundamentals rather than other factors that may drive stock price changes.     

卖空制度对企业融资的影响研究——基于融券卖空制度的检验

基于中国2010年实施融资融券制度的背景,利用分批扩容的准自然实验环境,检验卖空制度对企业融资的影响。结果发现：卖空制度的引入对企业外源融资能够起到抑制作用,这来源于外部治理作用所带来的过度融资的减少、市场信息反馈效应所带来的企业融资——股票价格敏感度的提升,以及融资成本的提高。进一步分析发现,企业外源融资的减少是有效率的,能够提高企业资源配置效率,促进资本结构动态调整。因此,卖空制度有助于抑制企业的过度融资,提高企业资源配置效率,对资本市场的稳定运转和完善大有裨益。     

Insider Selling and IPO Price Premium

We examine insider selling for initial public offering (IPO) firms using a sample of 1868 IPOs between 1988 and 2012. We find that overvalued IPOs have higher probability of offering secondary shares, higher proportion of secondary shares offered, and more upward revision in the total number of shares offered. They also have higher probability of insider sale in the open market both before and after lockup expiration. The size of insider sale in the open market also increases with the degree of overvaluation. The results are consistent with the hypothesis that IPO insiders try to sell their shares opportunistically into overvalued markets.     

Intraday Price Discovery in the DJIA Index Markets

Abstract:  This paper explores the dynamics of price discovery between the Dow Jones Industrial Average (DJIA) index and its three derivative products: the DIAMOND exchange-traded fund (ETF), the floor-traded regular futures, and the electronically traded mini futures. Even though the American Stock Exchange is the primary listing exchange for the ETF, the analysis indicates that the electronically traded ETF on the Archipelago (ArcaEx) electronic communications network dominates the price discovery process for DIAMOND shares. The E-mini futures contribute the most to price discovery, followed by the ArcaEx DIAMOND. The DJIA index and regular futures contribute least to price discovery. The analysis is repeated using the derivatives of the S&P 500 index as a robustness check. The results indicate that multi-market trading ensures greater pricing efficiency. Informed traders favor electronic trading because of immediate and anonymous trade execution.     

Interaction Between Short Selling and Potential Insider Selling in the IPO Aftermarket

We document the determinants of short interest in newly public firms during the lockup period and how short interest influences the valuation effects surrounding lockup expiration. We find that the short interest is larger for stocks that have more downward price potential at lockup expiration. We also find that the stocks that are subjected to larger short positions experience more pronounced negative valuation effects upon lockup expiration. Finally, we find that the stocks with a larger short interest position just after lockup expiration experience weaker returns during the following the six-month period.     

Short Selling Pressure,Stock Price Behavior,and Management Forecast Precision: Evidence from a Natural Experiment

Using a natural experiment (Regulation SHO), we show that short selling pressure and consequent stock price behavior have a causal effect on managers’ voluntary disclosure choices. Specifically, we find that managers respond to a positive exogenous shock to short selling pressure and price sensitivity to bad news by reducing the precision of bad news forecasts. This finding on management forecasts appears to be generalizable to other corporate disclosures. In particular, we find that, in response to increased short selling pressure, managers also reduce the readability (or increase the fuzziness) of bad news annual reports. Overall, our results suggest that maintaining the current level of stock prices is an important consideration in managers’ strategic disclosure decisions.     

Implications of Short Selling for Corporate Finance

Corporate managers often view short sellers as market manipulators whose actions drive their company's stock price below intrinsic value. But recent academic research suggests that some short sellers are effective in processing publicly available information and that their short selling may provide useful information to market participants. This article summarizes the authors’ own published research, which provides evidence of informed short selling by linking it to changes in corporate fundamentals. More specifically, the authors’ findings indicate that increases in short interest are reliable indicators of an economically (as well as statistically) significant decline in a company's operating performance over the following three years. And when examining changes in short interest around announcements of seasoned equity offerings, the authors also find a negative relation between an increase in short interest and future operating performance. In addition, they find that the greater the increase in short interest in the period leading up to the SEO announcement, the more negative is the stock‐price response to the announcement itself. The authors’ findings suggest that corporate managers can benefit from monitoring the short‐selling activity in their company's stock. Short‐selling data can be used to reassess corporate strategy or rethink major corporate decisions that have been announced but not carried out, and take preemptive actions to forestall impending future declines in performance and so preserve value.     

Intraday Stock Price Reactions to Interim-Quarter versus Fourth-Quarter Earnings Announcements

This study investigates intraday patterns of quarterly return-earnings relations. We find that fourth quarter announcements exhibit a lower earnings response coefficient but a more rapid adjustment to new equilibrium levels of prices and a higher R2 than interim quarter announcements. While prior short event window studies document that interim quarter earnings have greater explanatory power than fourth quarter earnings or annual earnings, our analysis indicates that the prior results may be driven by the use of two-day event window that is much wider than what it takes for the market to adjust to fourth quarter announcements.     

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。     

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.     

Short Selling and Earnings Management: A Controlled Experiment

During 2005 to 2007, the SEC ordered a pilot program in which one‐third of the Russell 3000 index were arbitrarily chosen as pilot stocks and exempted from short‐sale price tests. Pilot firms’ discretionary accruals and likelihood of marginally beating earnings targets decrease during this period, and revert to pre‐experiment levels when the program ends. After the program starts, pilot firms are more likely to be caught for fraud initiated before the program, and their stock returns better incorporate earnings information. These results indicate that short selling, or its prospect, curbs earnings management, helps detect fraud, and improves price efficiency.     

证券市场中卖空交易机制基本功能研究

本文通过利用境外实证研究结果和境外市场的数据进行实证这两种方式对国外证券市场中卖空交易机制的基本功能进行深入的研究.研究结果表明,证券市场中的卖空交易机制能发挥稳定市场、价格发现和提供流动性的功能,但卖空机制的宏观调控功能的实际效果并不理想.     

Intraday Price Formation in U.S. Equity Index Markets

The market for U.S. equity indexes presently comprises floor‐traded index futures contracts, exchange‐traded funds (ETFs), electronically traded, small‐denomination futures contracts (E‐minis), and sector ETFs that decompose the S&P 500 index into component industry portfolios. This paper empirically investigates price discovery in this environment. For the S&P 500 and Nasdaq‐100 indexes, most of the price discovery occurs in the E‐mini market. For the S&P 400 MidCap index, price discovery is shared between the regular futures contract and the ETF. The S&P 500 ETF contributes markedly to price discovery in the sector ETFs, but there are only minor effects in the reverse direction.