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.     

Short-selling,margin-trading,and stock liquidity: Evidence from the Chinese stock markets

This paper examines the impacts of two forms of leveraged trading—margin trading and short selling—on the trading liquidity of individual stocks in China. We find that trading liquidity for relevant stocks generally improves after restrictions on leveraged trading are removed. However, margin trading and short selling have opposite impacts on liquidity. During ordinary periods, margin trading benefits liquidity, whereas short selling damages liquidity; however, during market downturns, their roles are reversed. We also provide evidence suggesting that short sellers are informed traders in China and that short selling reduces stock liquidity because of the increased risk of adverse selection faced by uninformed traders.     

Stock price clustering on option expiration dates

This paper presents striking evidence that option trading changes the prices of underlying stocks. In particular, we show that on expiration dates the closing prices of stocks with listed options cluster at option strike prices. On each expiration date, the returns of optionable stocks are altered by an average of at least 16.5 basis points, which translates into aggregate market capitalization shifts on the order of $9 billion. We provide evidence that hedge rebalancing by option market makers and stock price manipulation by firm proprietary traders contribute to the clustering.     

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.     

Noise trading and the price formation process

This study proposes the dispersion in daily net initiated order flow across brokers as a proxy for the level of noise trading in a stock, and applies this proxy to test some basic implications of market microstructure theory. We use data from the Australian Stock Exchange, a computerized limit order market where price, quantity, and broker identity for each incoming order are shown on broker screens. We find daily movements in our noise measure are positively associated with trading volume and market depth, and negatively related to the bid-ask spread. We find monthly movements in our noise measure are negatively associated with the probability of informed trading, and positively correlated with the arrival rate of uninformed traders. We also find the sensitivity of stock prices to net initiated order flow decreases in the level of noise trading. In addition we find that, after controlling for noise trading, the sensitivity of stock prices to net initiated order flow is significantly greater on Mondays. These empirical results consistently support the implications of various models of market microstructure, suggesting that our proxy provides useful information as a daily measure of noise trading.     

Option trading: Information or differences of opinion?

This paper investigates the motive of option trading. We show that option trading is mostly driven by differences of opinion, a finding different from the current literature that attempts to attribute option trading to information asymmetry. Our conclusion is based on three pieces of empirical evidence. First, option trading around earnings announcements is speculative in nature and mostly dominated by small, retail investors. Second, around earnings announcements, the pre-announcement abnormal turnovers of options seem to predict the post-announcement abnormal stock returns. However, once we control for the pre-announcement stock returns, the predictability completely disappears, implying that option traders simply take cues from the stock market and turn around to speculate in the options market. Third, cross-section and time-series regressions reveal that option trading is also significantly explained by differences of opinion. While informed trading is present in stocks, it is not detected in options.     

The impact of competition and information on intraday trading

In a dynamic model of financial market trading multiple heterogeneously informed traders choose when to place orders. Better informed traders trade immediately, worse informed delay – even though they expect the market to move against them. This behavior generates intraday patterns with decreasing spreads, decreasing probability of informed trading (PIN), and increasing volume. We predict that policies that foster market entry improve the welfare of uninformed traders and lead to increased market participation by incumbent traders. Technological advances that lead to better signal processing also encourage market participation and increase volume but at the expense of uninformed traders’ welfare.     

Do option markets substitute for stock markets? Evidence from trading on anticipated tender offer announcements

Using a sample of cash tender offers occurring between 1993 and 2002, we find evidence that the options market has become the preferred venue for traders attempting to profit on anticipated announcements. Options offer advantages relative to stocks. Traders gain leverage by trading in options and multiple options contracts on an individual stock. The results of our study indicate that a substitution effect does exist. Abnormal volume in the option market replaces abnormal volume in the stock market prior to cash tender offer announcements, and this abnormal option volume precedes abnormal stock volume for targets with or without traded options.     

Can margin traders predict future stock returns in Japan?

A growing body of literature suggests that investor sentiment affects stock prices both at the firm level and at the market level. This study examines the relationship between investor behavior and stock returns focusing on Japanese margin transactions using weekly data from 1994 to 2003. Margin trading is dominated by individual investors in Japan. In analysis at the firm level, we find a significant cross-sectional relationship between margin buying and stock returns. Both market-level and firm-level analyses show that margin buying traders follow herding behavior. They seem to follow positive feedback trading behavior for small-firm stocks and negative feedback trading behavior for large firm stocks. Our results show that information about margin buying helps predict future stock returns, especially for small-firm stocks at short horizons. The predictive power does not diminish even after controlling for firm size and liquidity.     

Explaining Intraday Pattern of Trading Volume from the Order Flow Data

Based on a comprehensive order flow data from the Taiwan stock market, this study examines directly how the intraday pattern of trading volume is related to the trading behavior of both informed and uninformed traders. The results indicate that both informed and uninformed investors have a strong desire to place orders at the market open and the close. Most of the orders at the market open are conservative and hence are waiting orders for price priority. The findings show that intraday trading volume as well as the real orders from both types of investors are J-shaped. In addition, both information and liquidity trading can explain the intraday pattern of trading volume. However, the impact of liquidity trading on volume is slightly higher than that of information trading.     

Put-call parity and the informational efficiency of the German DAX-index options market

Using transaction data for options on the German stock index (DAX), we examine the informational efficiency of this relatively new options market. Because DAX options are European style and the underlying index is a performance index, we avoid problems due to dividend estimation and the assessment of the early-exercise effect, which are encountered in existing studies. Ex-post and ex-ante tests are carried out to simulate trading strategies for exploiting put-call parity violations. We find that ex-post profits diminish dramatically when the implementation of the arbitrage strategies is delayed and/or after transaction costs are accounted for. In general, however, arbitrage restrictions, which rely on short selling of the component stocks of the index, tend to be violated more severely than those relying on long positions in these stocks. Given the short-selling restrictions in Germany, these apparent arbitrage opportunities cannot be easily exploited in practice. Furthermore, the results for different subsamples suggest that traders were subject to a learning process in pricing these relatively new instruments.     

Individual Investors and Volatility

We show that retail trading activity has a positive effect on the volatility of stock returns, which suggests that retail investors behave as noise traders. To identify this effect, we use a reform of the French stock market that raises the relative cost of speculative trading for retail investors. The daily return volatility of the stocks affected by the reform falls by 20 basis points (a quarter of the sample standard deviation of the return volatility) relative to other stocks. For affected stocks, we also find a significant decrease in the magnitude of return reversals and the price impact of trades.     

The impact of short-selling and margin-buying on liquidity: Evidence from the Chinese stock market

We propose a framework based on limit order book to analyze the impact of short-selling and margin-buying on liquidity. We show that when short-sellers are perceived as informed, adverse selection may lead to uninformed traders withdrawing their limit orders. Given that the Chinese stock market has strong information asymmetry and a high proportion of uninformed traders, we predict that the pilot program launched in March 2010, which lifts restrictions on short-selling and margin-buying for a designated list of stocks, may have a negative impact on liquidity. We perform difference-in-differences tests and show evidence that allowing for short-selling and margin-buying indeed has a significantly negative impact on liquidity for stocks on the designated list. In particular, the negative impact on liquidity is more pronounced for stocks with high information asymmetry. Nevertheless, when short-selling volume dries up due to regulation changes in August 2015, i.e., the “T+1” trading rule on short-selling, we show that consistent with model predictions, lifting restrictions on short-selling and margin-buying has a positive effect on liquidity.     

The options market maker exception to SEC Regulation SHO

Until 2008, options market makers engaged in bona fide market making were exempt from locate and certain close-out requirements for short sales (the “Exception”). This Exception applied only to short sales that qualified as bona fide hedges of options positions that were established before a stock went on the SEC Regulation SHO Threshold List. In this paper we examine the consequences of eliminating this close-out Exception. Specifically, we test the hypothesis that eliminating the Options Market Maker Exception to SEC Regulation SHO reduced the incentive to naked short sell stocks through the options market. We compare data from the second and fourth quarters of 2008. Consistent with our predictions, we find that eliminating the Exception led to fewer fails-to-deliver and higher stock borrow rates for optionable stocks as compared to non-optionable stocks. Further, removing the Exception reduced fails-to-deliver for optionable stocks when the price of borrowing stock was high. Finally, options market trading volume declined after the Exception was eliminated.     

Informed trading and liquidity in the Shanghai Stock Exchange

Dufour and Engle (J. Finance (2000) 2467) find evidence of increased presence of informed traders when the NYSE markets are most active. No such evidence, however, can be found by Manganelli (J. Financial Markets (2005) 377) for the infrequently traded stocks. This article investigates the issue of informed trading and its relation to liquidity in Shanghai Stock Exchange. Consistent with the hypothesis that information-based trade exists for all stocks, our findings suggest an increased presence of informed trading in both liquid and illiquid stocks when markets are active. Moreover, for the actively traded stocks, our results support the price formation model of Foster and Viswanathan (Rev. Financial Studies (1990) 593) that activities of informed traders deter uninformed investors from trading, thereby reducing market liquidity.     

Volume,volatility and information linkages in the stock and option markets

This paper examines the relationship between option trading activity and stock market volatility. Although the option market is uniquely suited for trading on volatility information, there is little analysis on how trading activity in this market is linked to stock price volatility. The bulk of the discussion tends to focus on whether trading activity in the stock market is informative about stock volatility. To analyze the information in option trading activity for stock market volatility, a sample of 15 stocks with the highest option trading volume is selected. For each stock, it is noted that the trading activities in the put and call option markets have significant explanatory power for stock market volatility. In addition, the results indicate that the call option trading activity has a stronger impact on stock volatility compared with that of the put options. Our results demonstrate that information and sentiment in the option market is useful for the estimation of stock market volatility. Also, the significance of the effects of option trading activity on stock price volatility is observed to be comparable to that of stock market trading activity. Furthermore, the persistence and asymmetric effects in the volatility of some stocks tend to disappear once option trading activity is taken into account.     

A Characterization of the Daily and Intraday Behavior of Returns on Options

The daily and intraday behavior of returns on Chicago Board Options Exchange options is examined. Option returns contain systematic patterns even after adjusting for patterns in the means and variances of the underlying assets. This is consistent with the hypothesis that informed trading in options can make the order flow in the options market informative about the value of the underlying asset, making options nonredundant. The intraday patterns in adjusted option return variances are further consistent with a model of strategic trading by informed and discretionary liquidity traders.     

The Information in Option Volume for Future Stock Prices

We present strong evidence that option trading volume containsinformation about future stock prices. Taking advantage of aunique data set, we construct put-call ratios from option volumeinitiated by buyers to open new positions. Stocks with low put-callratios outperform stocks with high put-call ratios by more than40 basis points on the next day and more than 1% over the nextweek. Partitioning our option signals into components that arepublicly and nonpublicly observable, we find that the economicsource of this predictability is nonpublic information possessedby option traders rather than market inefficiency. We also findgreater predictability for stocks with higher concentrationsof informed traders and from option contracts with greater leverage.     

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.     

The securitization of gold and its potential impact on gold stocks

We study the market impact of a very successful financial innovation – the SPDR Gold Trust exchange-traded fund (GLD). GLD holds physical gold, and provides traders with a convenient and cost-effective way to gain exposure to gold. We find that after the introduction of GLD, the liquidity of gold company stocks declined, and their adverse-selection risk increased. Over the two-month period after GLD’s introduction, the stocks’ relative effective bid-ask spreads increased by over 15%, while their adverse-selection cost, as measured by the price impact of trades, went up by more than 30%. Gold stocks also experienced significant negative abnormal returns (−12% on average) in the month after GLD started trading. Our findings suggest that GLD attracted traders, especially uninformed traders, away from gold company stocks, and that the resulting negative demand shocks and decrease in the stocks’ liquidity caused their prices to decline. Our results show that existing securities can be seriously adversely affected when a new security enters the market.