卖空机制与食品安全——基于溢出效应的视角

卖空机制通过威慑效应约束厂商的自利动机,为食品安全治理提供了一种可行的资本市场途径。本文利用2015—2018年原国家食品药品监督管理总局披露的食品抽检数据,考察卖空强度对地区食品质量的影响。采用食品类上市公司融券余额在流通市值中占比的加权平均值度量地区卖空强度,体现了食品企业受到的卖空威慑压力。结果发现,卖空强度越大,当地整体的食品抽检质量越好。机制分析发现,卖空威胁在提升上市食品企业产品质量的同时,通过供应链协同、同群效应以及减少信息不对称的途径传导至同地区的其他企业,产生了食品质量治理的溢出效应。异质性分析显示,卖空对食品安全治理的溢出效应在要素市场发育不足、法制相对不健全和欠发达地区更加明显,卖空作为外部监管的补充机制发挥了食品安全治理的功能。因此,完善融资融券制度,适时合理地将食品类上市公司纳入融券标的,为惩治劣质食品提供资本市场手段,对确保食品安全问题“零容忍”具有现实意义。     

中国式卖空机制与高管减持——基于融资融券分步扩容的准自然实验

本文以我国的融资融券制度为背景,结合双重差分模型,研究卖空机制对上市公司高管减持行为的影响。研究发现,相对于非融券标的,可融券标的公司高管的月减持比例在允许卖空后下降22%,这种抑制作用在小规模、高盈余平滑度以及非国有公司中体现得更为明显。其次,成为可融券标的后,股价定价效率提高,高管减持收益显著下降。进一步地,本文将高管的减持行为分为定期性与投机性两类,发现卖空机制显著抑制了高管基于信息优势和股价偏差的投机性减持行为。     

放松卖空管制能够抑制并购商誉泡沫吗？

本文以我国放松卖空管制作为切入点,系统检验了其对并购商誉泡沫的影响。研究发现,放松卖空管制之后,超额商誉显著下降,同时商誉资产也显著下降,且该效应在民营控股公司中更显著;机制检验发现,卖空通过吸引更多分析师跟踪、增加对管理者的激励来抑制商誉泡沫;进一步研究发现,在市场化水平较高、行业竞争度较低的情形下,卖空机制对商誉泡沫的抑制作用更强。本文的研究结论丰富了卖空和并购商誉领域的文献,并为以市场导向原则化解并购商誉泡沫提供了新思路和新范式。     

Short-selling activities in the time of COVID-19

This study examines the daily short-selling activities in the U.S. market during the early 2020 outbreak of the COVID-19 global pandemic. Our findings indicate firms that are more sensitive to the shock (i.e., with high foreign exposure, low financial or operating flexibility, or high supply-chain exposure) were shorted more heavily. Moreover, short-selling activities during the COVID-19 pandemic, blamed for triggering stock market crashes, were primarily concentrated around overpriced stocks. This finding supports the argument that short selling plays a prominent role in improving price discoveries. Our research provides timely empirical evidence supporting the U.S. Securities and Exchange Commission's (SEC) non-intervention approach in banning short selling in the U.S. market.     

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.     

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.     

做空机制对我国股市波动性影响的实证分析

我国融资融券业务于2010年3月31日正式启动,而作为一种资本市场机制,做空机 制一直以来都饱受理论界和实务界的争议,做空机制对市场波动的影响尚未达成一致结论。本 文考察了做空机制与市场波动性之间的关系。研究发现：（1）在样本期间内,市场波动与做空 机制之间存在长期的稳定关系;（2）买空交易会在一定程度上增加市场波动,而卖空交易会 在一定程度上降低市场波动,但是二者的影响均有限;（3）综合来看,做空机制并不会引起证 券市场的异常波动,即使市场出现了大幅度的震荡,也不是由于卖空机制本身造成的;（4）本 文认为进一步完善做空机制尤其是卖空交易机制有助于稳定市场。本文结论对于评估做空机 制对市场波动的影响,防范经济冲击风险以及加强市场监管具有重要启示。     

An empirical and institutional examination of post-crisis capital flows—Thailand case

In this paper, we developed and estimated a model of the Thai firm during the crisis. Our results indicate that firms with the highest debt-equity ratios suffered the steepest declines in earnings per share during the crisis from the financial distressed costs. We take this result as strong evidence for the credit channel. Surprisingly, firms with the largest market capitalizations suffered more than the smaller firms owing to their capital structure and financial leverage effect. We also witness asymmetric impact between the industries—exporters, importers and intermediate. We take this as evidence of different scale-effects on different industries, a feature that we do not explicitly model. In other words, the production effect is more pronouncing in import related industries than the export-oriented one. Note that firms that import intermediate goods also suffered greatly from the crisis from both credit and production channels. Taken together, our overall results indicate that the crisis damaged the earnings per share of firms more on credit channels than the production channels. There exists a peculiar tradeoff between benefits from currency devaluation to promote exports and severe adverse impact on both credit channel and asymmetric impact on production channel.     

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.     

Short-selling and cost of equity: evidence from China

In this study, we take advantage of the gradual lifting of the short-selling ban in China and find that firms affected by the lifting of the ban experience a lower cost of equity. In addition, the affected firms also incur less earnings management, higher market liquidity and higher investment efficiency. Further evidence shows that firms’ cost of equity increases after their stocks are no longer eligible for short selling. Our inferences are robust to alternative measures of cost of equity, and to using a propensity score-matched sample. Our study contributes to the literature by providing evidence that short sellers play a monitoring role in the Chinese stock markets and sheds light on the benefits of short selling in emerging markets.     

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.     

Private placement,share prices,volume and financial crisis: An emerging market study

Firms are increasingly resorting to private placements in recent years, yet there is no published study of emerging markets. There is a unique opportunity to study this behavior during a severe financial crisis, when firms resorted to private placements to recover financially distressed firms. Our analysis using data over fifteen years shows (a) a significant 2–3% positive share price reaction, affirming asymmetric information effect, (b) a significant volume activity, and (c) the price impact is different across a period of a major financial crisis. If the proceeds from placement are earmarked for investment, share price is negatively (positively) correlated during the crisis (non-crisis) periods. Our finding on regulation is inconsistent with prior reports in developed markets: this is explained by the stricter restrictions on trading of private issues in emerging market. These results provide modest new contributions to the literature on private placements.     

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.     

Short-selling bans and institutional investors' herding behaviour: Evidence from the global financial crisis

The literature on short-selling restrictions focusses mainly on a ban's impact on market efficiency, liquidity and overpricing. Surprisingly, little is known about the effects of short-sale constraints on herd behaviour. Since institutional investors have come to dominate mature stock markets and rely extensively on short sales, constraining these traders may influence the asset pricing process. We investigate six stock markets that faced bans during the recent global financial crisis. Our empirical evidence shows that short-selling restrictions exhibit either no influence on herding formation or induce adverse herding. This implies a higher dispersion of returns around the market compared to rational asset pricing, which can be interpreted as an increase in uncertainty among stock market investors.     

Why Muddy the Water? Short selling and the disclosure of proprietary information

The conventional wisdom of voluntary disclosure literature is that the major factor preventing firms from disclosing customer-related information is firms' concern for proprietary costs. However, non-disclosure may also happen when firms have bad news to hide and are concerned about short sellers using customer information to verify bad news about the firms. By implementing a difference-in-differences research design against the backdrop of the deregulation of short selling in China, we find that increased short-selling pressure discourages firms from disclosing the identities of major customers. The findings also reveal consistent evidence supporting the bad news hoarding hypothesis rather than the proprietary cost hypothesis. Overall, our study provides an alternative explanation for firms’ lack of disclosure of customer information.     

卖空与创新:A股公司融券试点的证据

本文依托中国A股市场2010年开始实施的融券试点,在通过多时点双重差分和倾向得分匹配等计量方法控制内生性的基础上,实证检验了卖空对上市公司创新行为的促进作用.结果 表明:(1)加入融券标的后,卖空公司的创新数量和创新质量都有显著提高;(2)对于金融市场欠发达、治理水平较差的公司,这种作用更明显;(3)在使用融券余额作为卖空势力的测度并用ETF基金持股比例作为工具变量进一步控制内生性以后,以上结论仍然成立.卖空有助于降低创新企业的信息不对称性和加强对经理人的薪酬激励,进而促进了企业的创新.因此,取消卖空限制将有助于中国企业的创新和资本市场的健康稳定发展.     

Short Sellers and Financial Misconduct

We examine whether short sellers detect firms that misrepresent their financial statements, and whether their trading conveys external costs or benefits to other investors. Abnormal short interest increases steadily in the 19 months before the misrepresentation is publicly revealed, particularly when the misconduct is severe. Short selling is associated with a faster time‐to‐discovery, and it dampens the share price inflation that occurs when firms misstate their earnings. These results indicate that short sellers anticipate the eventual discovery and severity of financial misconduct. They also convey external benefits, helping to uncover misconduct and keeping prices closer to fundamental values.     

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.     

An Empirical Investigation of Short-Selling Activity Prior to Seasoned Equity Offerings

We investigate the nature and magnitude of short-selling activity around seasoned equity offerings, the relation between short-selling activity and issue discounts, and the consequences of the Securities and Exchange Commission (SEC's) adoption of Rule 10b-21 in response to concerns about manipulative short-selling practices. Seasoned offerings are characterized by abnormally high levels of short selling and option open interest. Higher levels of such activity are related to lower expected proceeds from the issuance of new shares. Where it could not be circumvented, Rule 10b-21 appears to have curbed short-selling activity and reduced issue discounts.     

Do short sellers anticipate late filings?

Exploiting the setting of firms that are unable to disclose timely financial reports and thus must file with the U.S. Securities and Exchange Commission (SEC) the NT 10-K (Q) report, this study examines whether short sellers target firms with financial reporting weaknesses. We find that short interest increases in firms prior to the NT 10-K (Q) filing, suggesting that short sellers identify and target firms that cannot file their financial reports in a timely manner. Short selling is positively significantly related to subsequent late filing status, and is more pronounced in late filers with high newswire activity and with accelerated filing deadlines. Short selling of late filing firms is significantly negatively related to subsequent performance thereby suggesting that short sellers' trades pertinent to late filers are profitable. Overall, the results underscore a high information processing ability of short sellers in the setting of firms that exhibit financial reporting deficiencies.