The market microstructure approach to foreign exchange: Looking back and looking forward

Research on foreign exchange market microstructure stresses the importance of order flow, heterogeneity among agents, and private information as crucial determinants of short-run exchange rate dynamics. Microstructure researchers have produced empirically-driven models that fit the data surprisingly well. But FX markets are evolving rapidly in response to new electronic trading technologies. Transparency has risen, trading costs have tumbled, and transaction speed has accelerated as new players have entered the market and existing players have modified their behavior. These changes will have profound effects on exchange rate dynamics. Looking forward, we highlight fundamental yet unanswered questions on the nature of private information, the impact on market liquidity, and the changing process of price discovery. We also outline potential microstructure explanations for long-standing exchange rate puzzles.     

Limit order books and trade informativeness

In the microstructure literature, information asymmetry is an important determinant of market liquidity. The classic setting is that uninformed dedicated liquidity suppliers charge price concessions when incoming market orders are likely to be informationally motivated. In limit order book (LOB) markets, however, this relationship is less clear, as market participants can switch roles, and freely choose to immediately demand or patiently supply liquidity by submitting either market or limit orders. We study the importance of information asymmetry in LOBs based on a recent sample of 30 German Deutscher Aktienindex (DAX) stocks. We find that Hasbrouck's (1991) measure of trade informativeness Granger causes book liquidity, in particular that required to fill large market orders. Picking-off risk due to public news-induced volatility is more important for top-of-the book liquidity supply. In our multivariate analysis, we control for volatility, trading volume, trading intensity and order imbalance to isolate the effect of trade informativeness on book liquidity.     

LIQUIDITY AND ASSET PRICING UNDER THE THREE‐MOMENT CAPM PARADIGM

We examine whether the use of the three‐moment capital asset pricing model can account for liquidity risk. We also make a comparative analysis of a four‐factor model based on Fama–French and Pástor–Stambaugh factors versus a model based solely on stock characteristics. Our findings suggest that neither of the models captures the liquidity premium nor do stock characteristics serve as proxies for liquidity. We also find that sensitivities of stock return to fluctuations in market liquidity do not subsume the effect of characteristic liquidity. Furthermore, our empirical findings are robust to differences in market microstructure or trading protocols between NYSE/AMEX and NASDAQ.     

Multimarket trading and corporate bond liquidity

Global bonds are international securities traded and settled efficiently in multiple markets. This paper examines global bonds to evaluate the effects of multimarket trading on corporate bond liquidity and pricing. The results show that global bonds are significantly more liquid than similar-sized domestic bonds of the same issuers, and their liquidity advantage is reflected in higher market valuations. These findings support microstructure models that predict a positive relation between the number of potential investors and liquidity in over-the-counter markets, and help explain the increasing use of global bonds by corporate issuers.     

Information acquisition and market liquidity: Evidence from EDGAR search activity

We find that information acquisition is associated with an improvement in market liquidity. An empirical analysis of search activity using EDGAR as a proxy for information acquisition shows a theoretical gap in market microstructure models. We also find that EDGAR search is associated with nonsynchronicity, more efficient pricing, and negatively associated with the PIN measure. These results demonstrate that the main finding can be explained through improved incorporation of information into prices and use of sophisticated trading strategies by informed traders.     

Optimal informed trading in the foreign exchange market

We formulate a market microstructure model of exchange determination that we employ to investigate the impact of informed trading on exchange rates and on foreign exchange (FX) market conditions. With our formulation, we show how strategic informed agents influence exchange rates via both the portfolio-balance and information effects. We outline the connection which exists between the private value of information, market efficiency, liquidity and exchange rate volatility. Our model is also consistent with recent empirical research on the micro-structure of FX markets.     

Market microstructure

It is assumed that a collection of market agents can be treated as a statistical ensemble. Their market activities are depicted as the stochastic generation of market orders according to a Poisson process. The objective is to effectively describe the ‘temporal microstructure’, or moment-to-moment trading activities in asset markets. Two basic models, ‘dealership’ vs. ‘auction’ markets (and their variants) are put forth. Implications are drawn from each model. The implications include several testable hypotheses regarding the aggregate behavior of markets and market-makers as well as some qualitative insight into the transaction-to-transaction nature of realistic exchange processes.     

Commonality in liquidity and multilateral trading facilities

We use the introduction of two multilateral trading facilities (MTFs) to examine the impact of market fragmentation on commonality in liquidity. We find that the introduction of MTFs following the Markets in Financial Instruments Directive increases the comovement of stocks’ liquidity with MTF liquidity, while the comovement with the home market liquidity generally decreases. We also find that the higher the MTF trading volume or the number of MTFs trading a stock, the stronger the effect. Further, we find that the commonality in liquidity remains unchanged for a matched control sample of stocks that do not trade on MTFs.     

Modelling the buy and sell intensity in a limit order book market

In this paper, we model the buy and sell arrival process in the limit order book market at the Australian Stock Exchange. Using a bivariate autoregressive intensity model we analyze the contemporaneous buy and sell intensity as a function of the state of the market. We find evidence that trading decisions are both information as well as liquidity driven. Confirming predictions from market microstructure theory traders submit market orders by inferring from the recent order flow and the book with respect to upper and lower tail expectations as well as trading directions. However, traders also tend to take liquidity when the liquidity supply is high. Moreover, we find evidence that traders pay more attention to recent order arrivals and the current state of the order book than to the past order flow.     

Pricing Inefficiencies in Private Real Estate Markets Using Total Return Swaps

Efficient markets should guarantee the existence of zero spreads for total return swaps. However, real estate markets have recorded values that are significantly different from zero in both directions. Possible explanations might suggest non-rational behaviour by inexperienced market players or unusual features of the underlying asset market. We find that institutional characteristics in the underlying market lead to market inefficiencies and, hence, to the creation of a rational trading window with upper and lower bounds within which transactions do not offer arbitrage opportunities. Given the existence of this rational trading window, we also argue that the observed spreads can substantially be explained by trading imbalances due to the limited liquidity of a newly formed market and/or to the effect of market sentiment, complementing explanations based on the lag between underlying market returns and index returns.     

Competition in securities markets: the impact on liquidity

Competition for order flow is widely documented for U.S. markets, but is a relatively new phenomenon in European equities trading. Only with the Markets in Financial Instruments Directive, which went into effect in November 2007, did new trading venues emerge in Europe that for the first time ever seriously threatened established exchanges. Chi-X, one of the new competitors, has gained a considerable market share, eroding the traditional exchanges’ share of equities trading volumes. As the proliferation of new trading venues in Europe increases the danger of market fragmentation, this paper analyzes the potentially positive liquidity implications of a new trading venue. To this end, we examine the impact of the Chi-X market entry in French blue-chip equities on the liquidity of their home market. Our findings suggest that in consequence of the new competitor’s market entry, liquidity in the most actively traded stocks was enhanced on the home market during the observation period. This improvement exceeds the general European liquidity trend measured by a matching firm approach, which implies that despite fragmentation of order flow, market quality may even be enhanced.     

Circuit Breakers and Market Volatility: A Theoretical Perspective

This paper examines ex ante effects of circuit breakers (mandated trading halts). We show that circuit breakers, by causing agents to suboptimally advance trades in time, may have the perverse effect of increasing price variability and exacerbating price movements. We next consider a situation in which a circuit breaker causes trading to be halted in both a dominant (more liquid) and a satellite market. As agents switch from the dominant market to the satellite market, price variability and market liquidity decline on the dominant market and increase on the satellite market.     

City goes dark: Dark trading and adverse selection in aggregate markets

We investigate the impact of dark trading on adverse selection in an aggregate market for trading UK stocks. Dark trading is linked to lower adverse selection risk and improved informational efficiency and liquidity in the aggregate market, even as liquidity declines in the lit market with dark trading. However, there is a trading value-based threshold when dark trading starts to induce adverse selection. We estimate that this threshold varies from around 9% for the most liquid stocks to 25% for the least liquid stocks. The overall average threshold for the 288 FTSE 350 stocks in our sample is 14%.     

Market liquidity and institutional trading during the 2007–8 financial crisis

This paper shows that institutional sell-side herding increased bid–ask spreads and liquidity risk during the 2007–8 financial crisis. Such an impact on liquidity is most pronounced in firms with large numbers of institutions that sold the same stocks, that is, have correlated trades. For the same reason, we find institutional investors with a dedicated, buy-and-hold, investment style to be the least likely to herd; their trading activity did not affect stock market liquidity during the crisis. Our results are robust to alternative explanations, different test specifications and consistent with recent theories highlighting the negative impact of institutional trading activity on market liquidity during a crisis.     

Order flow, bid-ask spread and trading density in foreign exchange markets

This paper examines the implications of market microstructure for foreign exchange markets. We argue that the usual order flow model needs to be recast in broader terms to incorporate the transaction costs of liquidity and the limitation of price discovery through order flows that involve low trading density currencies. Using a daily data set, we find that order flows are inadequate when it comes to explaining the changes in the low trading density currencies. Alternatively, within the high trading density, both order flows and bid-ask spreads significantly affect the foreign exchange rate returns. Our findings suggest that the order flow model is better at incorporating these microstructure effects except for some currencies with a very high level of trading density.     

Informed speculation and hedging in a noncompetitive securities market

We examine an adverse selection model of trading in which bothinformed and uninformed traders are rational, maximizing agents.Replacing the price inelastic 'noise' or 'liquidity' traderswith strategic, utility-maximizing hedgers permits an explicitanalysis of the uninformed traders' welfare, and demonstratesthat several comparative statics obtained from the standardparadigm of Kyle (1984, 1985) are altered significantly uponendogenizing the trading motives of these agents. In contrastto extant models, market liquidity and price efficiency areboth nonmonotonic in the number of uninformed hedgers in themarket. Also, the welfare of hedgers monotonically decreaseswith the number of informed traders, despite greater competitionbetween the informed.     

Liquidity provision with limit orders and a strategic specialist

This article presents a microstructure model of liquidity provisionin which a specialist with market power competes against a competitivelimit order book. General solutions, comparative statics andexamples are provided first with un-informative orders and thenwhen order flows are informative. The model is also used toaddress two optimal market design issues. The first is the effectof 'tick' size - for example, eighths versus decimal pricing- on market liquidity. Institutions trading large blocks havea larger optimal tick size than small retail investors, butboth prefer a tick size strictly greater than zero. Second,a hybrid specialist/limit order market (like the NYSE) providesbetter liquidity to small retail and institutional trades, buta pure limit order market (like the Paris Bourse) may offerbetter liquidity on mid-size orders.     

On the Distribution of CBOE Option Trade Prices Occurring Between Consecutive Stock Trades

This paper examines the volume distribution of option trade prices that occurs when the underlying stock price remains constant. The width of these option trade price bands provides direct evidence on the law of one price and the redundancy of options assumed in many option models. We find that index option bands are narrower than equity option bands. Furthermore, for both equity and index options, puts have narrower bandwidths than calls. In general, option price bandwidth is narrow and can be explained by the minimum price movement allowed by the Chicago Board Options Exchanges (CBOE). This supports the single price law and the redundancy assumption. The existence of bid/ask quotes on the option does not materially affect the above results although it does alter the frequency of multiple option trade prices for a given underlying stock price. We note that over 53% of option trading volume occurs without bid/ask quotes on the CBOE compared to less than 15% a decade ago. Our results suggest that the effective bid/ask spread on options is probably no larger than the minimum price movements allowed by the CBOE. Furthermore, the need for the liquidity services of market makers may be declining if the decline in quoting activity stems from cross trading (i.e. trades not involving market makers).     

Time-Varying Arrival Rates of Informed and Uninformed Trades

We propose a dynamic econometric microstructure model of trading,and we investigate how the dynamics of trades and trade compositioninteract with the evolution of market liquidity, market depth,and order flow. We estimate a bivariate generalized autoregressiveintensity process for the arrival rates of informed and uninformedtrades for 16 actively traded stocks over 15 years of transactiondata. Our results show that both informed and uninformed tradesare highly persistent, but that the uninformed arrival forecastsrespond negatively to past forecasts of the informed intensity.Our estimation generates daily conditional arrival rates ofinformed and uninformed trades, which we use to construct forecastsof the probability of information-based trade (PIN). These forecastsare used in turn to forecast market liquidity as measured bybid-ask spreads and the price impact of orders. We observe thatPINs vary across assets and over time, and most importantlythat they are correlated across assets. Our analysis shows thatone principal component explains much of the daily variationin PINs and that this systemic liquidity factor may be importantfor asset pricing. We also find that PINs tend to rise beforeearnings announcement days and decline afterwards.     

Does high-frequency trading actually improve market liquidity? A comparative study for selected models and measures

The increasing volume of messages sent to the exchange by algorithmic traders stimulates a fierce debate among academics and practitioners on the impacts of high-frequency trading (HFT) on capital markets. By comparing a variety of regression models that associate various measures of market liquidity with measures of high-frequency activity on the same dataset, we find that for some models the increase in high-frequency activity improves market liquidity, but for others, we get the opposite effect. We indicate that this ambiguity does not depend only on the stock market or the data period, but also on the used HFT measure: the increase of high-frequency orders leads to lower market liquidity whereas the increase in high-frequency trades improves liquidity. We hypothesize that the observed decrease in market liquidity associated with an increasing level of high-frequency orders is caused by a rise in quote volatility.