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.     

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.     

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 AND MISPRICINGS WHEN FUNDAMENTALS ARE KNOWN: EVIDENCE FROM NYSE‐TRADED CLOSED‐END FUNDS

The larger a closed‐end fund's premium over its portfolio value, the more intensely it is sold short. This behavior should reduce mispricings. However, short selling affects neither the observed rate at which premia revert to fundamental values nor the rate of return on a fund's shares. This apparent contradiction can be explained as follows: short selling does reduce prices, but the effect is impounded into prices by the time short positions are tabulated by the NYSE each month. Consequently, the monthly short selling data do not predict future price movements.     

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。     

The impact of naked short selling on the securities lending and equity market

This paper examines the impact of naked short selling on equity markets where it is restricted to securities on an approved list. Consistent with Miller's (1977) intuition, stocks with the highest dispersion of opinions and short sale constraints are the only stocks to exhibit significant and negative abnormal returns in the post-event period. We also find slightly higher stock return volatility and a small reduction in liquidity when naked short sales are allowed. Overall, it impairs market quality (liquidity and volatility), although there appears to be some improvement in price efficiency in stocks with high short sale constraints.     

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。     

卖空机制能够约束内部人减持吗？——基于融资融券制度的经验证据

本文以我国放松卖空管制为视角,探究其对内部人减持的影响。研究表明,卖空机制能够抑制企业内部人减持行为。机制分析发现,卖空对内部人减持的抑制作用是通过缓解股权高溢价实现的。进一步研究表明,卖空能够抑制大股东、董事以及管理层减持,但对监事减持无影响;卖空能够降低内部人减持的获利程度,并且在内部人减持动机更大时,对内部人减持的抑制作用更强;卖空通过约束内部人减持提升了股票定价效率,还有助于降低内部人增持行为。本文的研究结论丰富了卖空和内部人减持领域的文献,并对政府部门完善制度设计具有启示意义。     

Short‐Horizon Return Predictability in International Equity Markets

This study measures the degree of short‐horizon return predictability of 50 international equity markets and examines how its variation is related to the indicators of equity market development. Two multiple‐horizon variance ratio tests are employed to measure the degree of return predictability. We find evidence that return predictability is negatively correlated with publicly available indicators of equity market development. Our cross‐sectional regression analysis shows that the per capita gross domestic product, market turnover, investor protection, and absence of short‐selling restrictions are correlated with cross‐market variations in return predictability.     

Impact of short selling activity on market dynamics: Evidence from an emerging market

With unique daily short sale data of Borsa Istanbul (stock exchange of Turkey), we investigate the dynamic relationship between short selling activity and volatility, liquidity and market return from January 2005 to December 2012 using a VAR(p)-cDCC-FIEGARCH(1,d,1) approach. Our findings suggest that short sellers are contrarian traders and contribute to efficient stock market in Turkey. We also show that increased short selling activity is associated with higher liquidity and decreased volatility. However this relation weakens during the financial turmoil of 2008. Our results indicate that any ban on short sales may be detrimental for financial stability and market quality in Turkey.     

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.     

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.     

Liquidation of a large block of stock

In the financial engineering literature, stock-selling rules are mainly concerned with liquidation of the security within a short period of time. This is practically feasible only when a relative smaller number of shares of a stock is involved. Selling a large position in a market place normally depresses the market if sold in a short period of time, which would result in poor filling prices. In this paper, we consider the liquidation strategy for selling a large block of stock by selling much smaller number of shares over a longer period of time. In particular, we treat the selling rule problem by using a fluid model in the sense that the number of shares are treated as fluid (continuous) and the corresponding liquidation is dictated by the rate of selling over time. The objective is to maximize the expected overall return. The underlying problem may be formulated as a stochastic control problem with state constraints. Method of constrained viscosity solution is used to characterize the dynamics governing the optimal reward function and the associated boundary conditions. Numerical examples are reported to illustrate the results.     

DIVERGENCE OF OPINION AND LONG‐TERM PERFORMANCE OF INITIAL PUBLIC OFFERINGS

Miller's hypothesis posits that divergence of opinion can lead to asset overvaluation and subsequent long‐term underperformance in markets (such as initial public offerings [IPOs]) with restricted short‐selling. Consistent with this hypothesis, we find that early‐market return volatility, a proxy for divergence of opinion, is negatively related to subsequent IPO long‐term abnormal returns. This relation holds after accounting for other factors that previous studies suggest affect long‐term abnormal returns for IPOs (including another proxy for divergence of opinion). Moreover, we find that this relation is stronger in IPO markets than in non‐IPO markets (where short‐selling restrictions are less stringent), again consistent with Miller's hypothesis.     

Market risk exposure of merger arbitrage in Australia

We investigate the risk‐return characteristics of merger arbitrage in the Australian market for corporate control, whereby hedge fund managers acquire companies subject to a takeover offer. On average, a strategy of buying target companies and short‐selling bidders making scrip offers would have generated an annual return of 30 per cent from 1985 to 2008, excluding transaction costs, compared to the return on the broader market of 12 per cent. However, performance is not market neutral, being positively associated with market returns during downturns and inversely related to market movements during rising markets. The payoffs to this strategy are analogous to a short straddle, whereby the investor is short a call and put option at the same exercise price. These results are consistent with large‐sample evidence from the United States and the United Kingdom and have not previously been documented in Australia, in which prior evidence is based only on cash deals during the 1990s.     

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.     

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.     

ARE PAIRS TRADING PROFITS ROBUST TO TRADING COSTS?

We examine the impact of trading costs on pairs trading profitability in the U.S. equity market, 1963 to 2009. After controlling for commissions, market impact, and short selling fees, pairs trading remains profitable, albeit at much more modest levels. Specifically, we document a risk‐adjusted return of about 30 basis points per month among portfolios of well‐matched pairs that are formed within refined industry groups. Pairs trading exhibits a lower risk and lower return profile than a short‐term reversal strategy that sorts stocks relative to their industry peers. Notably, both these types of contrarian investing are largely unprofitable after 2002.     

Arbitrage vs. informed short selling: Evidence from convertible bond issuers

Prior literature examines the effect of either informed or arbitrage short selling on equity markets. We test the relative importance of informed and uninformed short selling around convertible bond issues and earnings announcements for the same firms over the same time period. Convertible arbitrage short selling is associated with temporary price pressure, consistent with downward sloping demand curves. Earnings announcement short selling is consistent with informed traders who anticipate future returns. Firm-specific characteristics related to the cost of short selling similarly affect both informed and arbitrage short selling. Deal-specific characteristics capturing hedging demand also strongly determine convertible arbitrage short selling.