Closing price manipulation and the integrity of stock exchanges

Allegations of market manipulation abound in the popular press, particularly during the recent financial turmoil. However, many aspects of manipulation are poorly understood. The purpose of this thesis is to enhance our understanding of market manipulation by providing empirical evidence on the prevalence, effects and determinants of closing price manipulation. The first issue examined in this thesis is the prevalence of closing price manipulation. This thesis uses a hand collected sample of prosecuted closing price manipulation cases from US and Canadian stock exchanges, and methods that explicitly model the incomplete and non-random detection of manipulation. The results suggest that approximately 1.1% of closing prices are manipulated. For every prosecuted closing price manipulation there are approximately 300 instances of manipulation that remain undetected or not prosecuted. Closing price manipulation is more prevalent on larger exchanges than smaller ones, but is detected at a higher rate on small exchanges. Second, this thesis examines the effects of closing price manipulation. Using a sample of prosecution cases, this thesis finds that closing price manipulation is associated with large day-end returns, subsequent return reversals, increases in day-end spreads and increases in day-end trading activity. At the broader level of market quality, this thesis provides evidence from a laboratory experiment that closing price manipulation decreases both price accuracy and liquidity. Even the mere possibility of manipulation decreases liquidity and increases trading costs. The third issue analysed in this thesis is the determinants of closing price manipulation and its detection. Estimating an empirical model of manipulation and detection, this thesis finds that the likelihood of closing price manipulation is increased by smaller regulatory budgets, greater information asymmetry, mid to low levels of liquidity, month-end days and lower volatility. Manipulation is more likely to be detected when regulatory budgets are larger and when the manipulation causes abnormal trading characteristics. Further evidence from laboratory experiments suggests that regulation helps restore price accuracy by deterring some manipulation and making remaining manipulation less aggressive. These experiments also show that regulation has an insignificant effect on liquidity because participants in regulated markets still face relatively high uncertainty about the presence of manipulators. This thesis also examines how closing price manipulation is conducted and how other market participants respond. It develops an index of closing price manipulation that can be used to study manipulation in markets or time periods in which prosecution data are not available. It also provides a tool for the detection of manipulation, which can be used by regulators in automated surveillance systems. Finally, this thesis has implications for economic efficiency and policy. Closing price manipulation is significantly more prevalent than the number of prosecution cases suggests. Further, it harms both pricing accuracy and liquidity and therefore undermines economic efficiency. The prevalence of closing price manipulation can be reduced by increasing regulatory budgets, improving the accuracy of market surveillance systems by using the detection tools developed in this thesis, structuring markets such that participants are better able to identify manipulation, and implementing closing mechanisms that are difficult to manipulate. These actions would enhance market integrity and economic efficiency

Closing price manipulation and the integrity of stock exchanges

Allegations of market manipulation abound in the popular press, particularly during the recent financial turmoil. However, many aspects of manipulation are poorly understood. The purpose of this thesis is to enhance our understanding of market manipulation by providing empirical evidence on the prevalence, effects and determinants of closing price manipulation. The first issue examined in this thesis is the prevalence of closing price manipulation. This thesis uses a hand collected sample of prosecuted closing price manipulation cases from US and Canadian stock exchanges, and methods that explicitly model the incomplete and non-random detection of manipulation. The results suggest that approximately 1.1% of closing prices are manipulated. For every prosecuted closing price manipulation there are approximately 300 instances of manipulation that remain undetected or not prosecuted. Closing price manipulation is more prevalent on larger exchanges than smaller ones, but is detected at a higher rate on small exchanges. Second, this thesis examines the effects of closing price manipulation. Using a sample of prosecution cases, this thesis finds that closing price manipulation is associated with large day-end returns, subsequent return reversals, increases in day-end spreads and increases in day-end trading activity. At the broader level of market quality, this thesis provides evidence from a laboratory experiment that closing price manipulation decreases both price accuracy and liquidity. Even the mere possibility of manipulation decreases liquidity and increases trading costs. The third issue analysed in this thesis is the determinants of closing price manipulation and its detection. Estimating an empirical model of manipulation and detection, this thesis finds that the likelihood of closing price manipulation is increased by smaller regulatory budgets, greater information asymmetry, mid to low levels of liquidity, month-end days and lower volatility. Manipulation is more likely to be detected when regulatory budgets are larger and when the manipulation causes abnormal trading characteristics. Further evidence from laboratory experiments suggests that regulation helps restore price accuracy by deterring some manipulation and making remaining manipulation less aggressive. These experiments also show that regulation has an insignificant effect on liquidity because participants in regulated markets still face relatively high uncertainty about the presence of manipulators. This thesis also examines how closing price manipulation is conducted and how other market participants respond. It develops an index of closing price manipulation that can be used to study manipulation in markets or time periods in which prosecution data are not available. It also provides a tool for the detection of manipulation, which can be used by regulators in automated surveillance systems. Finally, this thesis has implications for economic efficiency and policy. Closing price manipulation is significantly more prevalent than the number of prosecution cases suggests. Further, it harms both pricing accuracy and liquidity and therefore undermines economic efficiency. The prevalence of closing price manipulation can be reduced by increasing regulatory budgets, improving the accuracy of market surveillance systems by using the detection tools developed in this thesis, structuring markets such that participants are better able to identify manipulation, and implementing closing mechanisms that are difficult to manipulate. These actions would enhance market integrity and economic efficiency

Price discovery in stock and options markets

Using new empirical measures of information leadership, we find that the role of options in price discovery is up to five times larger than previously thought. Approximately one-quarter of new information is reflected in options prices before being transmitted to stock prices, with options playing a more important role in price discovery around information events. Using unique data on traders prosecuted for insider trading, we find that they often choose to trade in options, attracted by their leverage, and when they do the options share of price discovery is higher. Our results help interpret conflicting findings in the existing literature

Asset pricing with downside liquidity risks

© 2016 INFORMS. We develop a parsimonious liquidity-adjusted downside capital asset pricing model to investigate whether phenomena such as downward liquidity spirals and flights to liquidity impact expected asset returns.We find strong empirical support for the model. Downside liquidity risk (sensitivity of stock liquidity to negative market returns) has an economically meaningful return premium that is 10 times larger than its symmetric analogue. The expected liquidity level and downside market risk are also associated with meaningful return premiums. Downside liquidity risk and its associated premium are higher during periods of low marketwide liquidity and for stocks that are relatively small, illiquid, volatile, and have high book-to-market ratios. These results are consistent with investors requiring compensation for holding assets susceptible to adverse liquidity phenomena. Our findings suggest that mitigation of downside liquidity risk can lower firms' cost of capital

Why does entrepreneurial orientation affect company performance?

© 2019 Strategic Management Society Research summary: To better understand why entrepreneurial orientation (EO) is positively associated with company performance, we propose and test a reconceptualization of how the components of EO (risk-taking, innovativeness, proactiveness) combine in driving performance. Drawing on financial economics theory, our conceptualization highlights that all three components positively contribute to performance, but in different ways. Risk-taking has a direct positive relationship with performance, which can be understood through the risk–return tradeoff that is central in financial economics theory. The relationship between risk-taking and performance is conditional on the level of innovativeness and thus innovativeness contributes to performance through its effect on the type of risk-taking. Proactiveness contributes to performance through its positive effect on the level of risk-taking. Managerial summary: This study analyzes three key drivers of company performance: risk-taking, innovativeness, and proactiveness. We show that constructive risk-taking is the central driver of company performance, mirroring the principle of risk and return in financial investment settings. Risk- taking that is associated with innovation has a particularly strong positive relationship with performance, consistent with innovation being a driver of growth and profitability. More proactive firms tend to take on more risk and thus also perform better than less proactive firms

Shorting at Close Range: A Tale of Two Types

Abstract We examine stock returns, order flow, and market conditions in the minutes before, during, and after recent short sales on the NYSE and Nasdaq. We find two very distinct types of short sales: those that provide liquidity, and those that demand it. Shorts that supply liquidity do so when spreads are unusually wide. These short sellers are also strongly contrarian, stepping in to initiate or increase a short position after fairly sharp share price rises over the past hour or so, and they tend to face greater adverse selection than other liquidity suppliers. In contrast, shorts that demand liquidity tend to be shortterm momentum traders. However, there is no evidence that liquidity-demanding short sellers are any different from other liquidity demanders. Overall, liquidity-providing short sales are important contributors to stock market quality, and regulators and policymakers should keep these salutary effects in mind. JEL classification: G14, G1

Automated authorship attribution using advanced signal classification techniques

In this paper, we develop two automated authorship attribution schemes, one based on Multiple Discriminant Analysis (MDA) and the other based on a Support Vector Machine (SVM). The classification features we exploit are based on word frequencies in the text. We adopt an approach of preprocessing each text by stripping it of all characters except a-z and space. This is in order to increase the portability of the software to different types of texts. We test the methodology on a corpus of undisputed English texts, and use leave-one-out cross validation to demonstrate classification accuracies in excess of 90%. We further test our methods on the Federalist Papers, which have a partly disputed authorship and a fair degree of scholarly consensus. And finally, we apply our methodology to the question of the authorship of the Letter to the Hebrews by comparing it against a number of original Greek texts of known authorship. These tests identify where some of the limitations lie, motivating a number of open questions for future work. An open source implementation of our methodology is freely available for use at https://github.com/matthewberryman/autho​r-detection.Maryam Ebrahimpour, Tālis J. Putniņš, Matthew J. Berryman, Andrew Allison, Brian W.-H. Ng, Derek Abbot

High frequency trading and co-movement in financial markets

© 2019 Elsevier B.V. Using the staggered entry of Chi-X in 12 European equity markets as a source of exogenous variation in high frequency trading (HFT), we find that HFT causes significant increases in comovement in returns and in liquidity. About one-third of the increase in return comovement is due to faster diffusion of market-wide information. We attribute the remaining two-thirds to correlated trading strategies of HFTs. The increase in liquidity comovement is consistent with HFT liquidity providers being better able to monitor other stocks and adjust their liquidity provision accordingly. Our findings suggest a channel by which HFT impacts the cost of capital