Informed Trading in Stock and Option Markets

We investigate the contribution of option markets to price discovery, using a modification of Hasbrouck's (1995) "information share" approach. Based on five years of stock and options data for 60 firms, we estimate the option market's contribution to price discovery to be about 17% on average. Option market price discovery is related to trading volume and spreads in both markets, and stock volatility. Price discovery across option strike prices is related to leverage, trading volume, and spreads. Our results are consistent with theoretical arguments that informed investors trade in both stock and option markets, suggesting an important informational role for options.     

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.     

Information flow between the stock and option markets: Where do informed traders trade?

This paper investigates the flow of information between the equity and options markets. We argue that informed traders, in deciding where to place their trades, are not entirely indifferent to option moneyness, degree of information asymmetry, and option liquidity. Unlike some previous studies that find information to flow unilaterally from equity to options markets, we control for the above factors and discover feedback relations between trades in out-of-the-money (OTM) options and the underlying equities. The finding is consistent with the pooling equilibrium hypothesis, which asserts that informed traders trade in both the equity and options markets. Some informed traders are probably attracted to the out-of-the money options because of their higher liquidity, lower premiums, and higher delta-to-premium ratios, hence, lending support to the liquidity and leverage hypothesis.     

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.     

Slow diffusion of information and price momentum in stocks: Evidence from options markets

This paper investigates the source of price momentum in the stock market using information from options markets. We provide direct evidence of the gradual information diffusion model in Hong and Stein (1999): momentum profits are larger for stocks whose information diffuses slowly into the stock market. We exploit the options markets to identify stocks with slow information diffusion speed. As informed traders trade options to realize the information that has not been fully incorporated in the stock price, we are able to enhance the momentum strategy by selecting winner/loser stocks with high growth/large drop in call option implied volatility. Our empirical strategy generates a risk-adjusted alpha of 1.8% per month over the 1996–2011 period, during which the simple momentum strategy fails to perform. The results are robust to the impact of earnings announcement, transaction costs, industry concentration, and choice of options’ moneyness and time-to-maturity. Finally, our finding is not driven by existing stock- or option-related characteristics that are known to improve momentum.     

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.     

Informed Trading Around Earnings Announcements: Another Look

This study is an empirical test of the Easley, O'Hara, and Srinivas (1998) multimarket sequential trade model of stock and option markets. We employ two approaches to determine the information content of signed stock and option trades executed around quarterly earnings announcements. The first approach expands the vector autoregression (VAR) technique of Hasbrouck (1991a) to include signed option trade volumes and inter‐trade durations. Estimates from the VAR models provide insight into whether both equity and option trades are viewed as informative by the equity specialist. The second approach focuses on the information content of the earnings releases to determine whether signed equity and option trades executed prior to the announcements are informed. Results indicate that although informed traders prefer to transact in both markets around earnings announcements, option market transactions contain no incremental information.     

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.     

Tipping and Option Trading

This study examines options’ market behavior before analysts’ initiations. We find abnormal trading activity in the options market several days prior to the release of analysts’ initiations. Informed traders recognize the content and timing of the initial recommendations. We determine that informed trading is attributed to information leakage rather than savvy investors’ stock‐picking ability. We also find a significant information transmission from the options market to the underlying equity market around the event. Our results are consistent with the tipping hypothesis and confirm the informational role of equity options.     

The “make or take” decision in an electronic market: Evidence on the evolution of liquidity

This paper uses experimental asset markets to investigate the evolution of liquidity in an electronic limit order market. Our market setting includes salient features of electronic limit order markets, as well as informed traders and liquidity traders. We focus on the strategies of the traders and how these are affected by trader type, characteristics of the market, and characteristics of the asset. We find that informed traders use more limit orders than do liquidity traders. Our main result is that liquidity provision shifts as trading progresses, with informed traders increasingly providing liquidity in markets. The change in the behavior of the informed traders seems to be in response to the dynamic adjustment of prices to information; they take (provide) liquidity when the value of their information is high (low). Thus, a market-making role emerges endogenously in our electronic markets and is ultimately adopted by the traders who are least subject to adverse selection when placing limit orders.     

Strategic trading and learning about liquidity

Many practitioners point out that the speculative profits of institutional traders are eroded by the difficulty in gauging the price impact of their trades. In this paper, we develop a model of strategic trading where speculators face such a dilemma because of incomplete information about time-varying market liquidity. Unlike the competitive market makers that they trade against, informed traders do not know the distribution of liquidity (“noise”) trades. Instead, they have to learn about liquidity from past prices and trading volume. This learning implies that strategic trades and market statistics such as informational efficiency are path-dependent on past market outcomes. Our paper also has normative implications for practitioners.     

Financial Markets Where Traders Neglect the Informational Content of Prices

We model a financial market where some traders of a risky asset do not fully appreciate what prices convey about others' private information. Markets comprising solely such “cursed” traders generate more trade than those comprising solely rationals. Because rationals arbitrage away distortions caused by cursed traders, mixed markets can generate even more trade. Per‐trader volume in cursed markets increases with market size; volume may instead disappear when traders infer others' information from prices, even when they dismiss it as noisier than their own. Making private information public raises rational and “dismissive” volume, but reduces cursed volume given moderate noninformational trading motives.     

Information Asymmetry,Trade Size,and the Dynamic Volume‐Return Relation: Evidence from the Australian Securities Exchange

This paper investigates the influence of information asymmetry on the cross‐sectional variation of volume‐return relation. We find that the dynamic volume‐return relation within medium‐size trades has the most significant response to the degree of information asymmetry. We also show that the effect of information asymmetry on the volume‐return dynamics migrates to small‐size trades in recent years, especially in larger stocks. These results are consistent with the notion that informed traders prefer medium‐size trades and this preference has shifted to small‐size trades. Our findings highlight the importance of incorporating informed traders’ trade‐size decision in the examination of the dynamic volume‐return relation.     

Market Statistics and Technical Analysis: The Role of Volume

We investigate the informational role of volume and its applicability for technical analysis. We develop a new equilibrium model in which aggregate supply is fixed and traders receive signals with differing quality. We show that volume provides information on information quality that cannot be deduced from the price statistic. We show how volume, information precision, and price movements relate, and demonstrate how sequences of volume and prices can be informative. We also show that traders who use information contained in market statistics do better than traders who do not. Technical analysis thus arises as a natural component of the agents' learning process.     

Audit quality and information asymmetry between traders

In this study, we investigate the association between audit quality and information asymmetry between informed and uninformed traders. We employ three proxies for information asymmetry – absolute price differences, absolute volatility differences, and absolute differences in the long/short ratio of trades – between US stock and options markets and represent audit quality through the appointment of Big n and industry specialist auditors. For a sample of 4062 firm‐years between 2002 to 2005, our results indicate that the appointment of Big n and industry specialist auditors is associated with lower information asymmetry measures. Our results are consistent with audit quality playing a role in the quality of financial reporting information and flowing through to the allocation of information among traders.     

An empirical investigation of large trader market manipulation in derivatives markets

Using account-level transaction data in options and futures markets, we investigate the existence of market manipulation, which is the ability of large traders to trade strategically, impacting prices and making abnormal profits. First, large trader’s option positions have a quantity impact on the underlying asset’s price. Second, large traders generate significantly positive alphas from trading options and futures. Among the different investor types, proprietary dealers generate the largest positive alphas. Third, these abnormal returns are consistent with strategic trading and cross-market manipulation. The evidence supports market manipulation across the options and futures markets, but not within the futures market itself.     

VPIN,liquidity, and return volatility in the U.S. equity markets

We examine the volume-synchronized probability of informed trading metric (the VPIN flow toxicity metric, developed by Easley, Lopez de Prado, & O'Hara, 2012) as a real-time risk management tool for liquidity deteriorations in the U.S. equity markets. We find that VPIN provides information about market liquidity and stock return volatility on ex-ante basis. These results indicate that VPIN can be a useful risk-management tool for market makers, regulators and traders in the U.S. equity markets. We also document that VPIN is negatively associated with volume and number of trades, but positively associated with trade size and volume fragmentation. These findings suggest that VPIN indicates the adverse selection problem of liquidity providers by capturing the information in volume.     

Trade Size Preference of Informed Traders in Indian Equity Markets

This study utilized high frequency transactions data to analyze the trade size preference of informed traders in Indian equity markets. It is observed that informed traders at an aggregate level adopt stealth trading strategy, wherein they prefer medium sized trades over large sized trades in order to camouflage their private information. However, the stealth trading behavior varies across stocks, wherein informed traders prefer more large sized trades on firms that are part of an index compared to non-index firms. Trading behavior also varies across other market conditions. It has been noted that informed traders prefer large sized trades during periods of high market thickness, negative returns, and low volatility. This study also provides a rationale for such varied behavior of informed traders.     

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.     

Cross-market informed trading in the CDS and option markets

This paper analyzes how informed traders balance leverage and liquidity in making cross-market trading decisions. Our findings are three-fold. Using daily data on the actively traded North American CDX Investment Grade and High Yield indexes from 2010 to 2017, first, we find robust evidence that, when the credit default swap (CDS) market is illiquid, informed traders do not hesitate to exploit their information advantage in the option market, and this manifests mainly for negative credit news. Second, we find that informed trading occurs predominantly in the option market for low-rated firms due to high adverse selection risk in the CDS market. Third, there is strong evidence of informed trading taking place in the CDS market for financial firms and we argue that this is due to the interdealer network through which CDS dealers obtain private information about other financial firms and their privileged position as market makers to be able to disguise their informed trades as ordinary market-making activities. Finally, we propose re-thinking market efficiency and how to advance it in a direction which does not privilege a small circle of financiers or create monopoly while keeping the markets liquid and tranquil at all times.