A SIMPLE MODEL OF BID-ASK SPREAD AND SEARCH

This paper analyzes a simple search model of market making in which the agents can choose between searching for a trading partner or trading through the market-maker. Explicit solutions for the equilibrium search intensities and the bid-ask spread have been provided. Equilibrium search intensities and the bid-ask spread reflect the strategic interaction between the agents and the market-maker: an increase in the bid-ask spread results in higher search intensities. The bid-ask spread, on the other hand, reacts negatively to an increase in the search intensities (due to lower search costs, higher efficiency of search, or higher gains from a match). It is also shown that the introduction of a market-maker increases the seller's reservation price and decreases the buyer's reservation price, hence narrowing the price dispersion.     

VOLATILITY AND LIQUIDITY AT NYSE OPENING CALLS: A CLOSER LOOK

The literature suggests that the bid-ask spread is responsible, at least in part, for greater price volatility and more negative autocorrelation at the open than at the close. In this study, we find that these phenomena are not related to the bid-ask spread, but are related instead to pricing errors by specialists or limit-order traders around the open. We use George, Kaul, and Nimalendran's (1991) model, which is less biased than Roll's (1984) model, to estimate the implied spread. The results show that, on average, the implied spread earned by liquidity suppliers is lower at the open than at the close. These results refute the contention that specialists exploit their monopoly position and earn a higher profit at the opening call. The evidence is consistent with the hypothesis that specialists set a lower cost of immediacy to encourage trading and the release of more information at the opening call. This could reduce information asymmetry and make subsequent trades in the continuous market more profitable.     

Liquidity skewness in the London Stock Exchange

We study liquidity on the London Stock Exchange. We find that the average bid-ask spread declines, but that the skewness of the spread increases. These results are robust to firm size, trading volume and price level. Our findings hold when the bid-ask spread is estimated utilising high frequency data. We find that the bid-ask spread prior to earnings announcements dates is significantly higher than that of post earnings announcements, suggesting that asymmetric information has driven the increase in liquidity skewness. We also find that the effect of earnings announcements is more pronounced in the 2007 global financial crisis, consistent with the notion that extreme market downturns amplify asymmetric information. Our overall evidence also implies that increased competition and transparent trading environments limit market makers' abilities to cross-subsidize bid-ask spreads between periods of high and low levels of asymmetric information.     

Optimal mean-reversion strategy in the presence of bid-ask spread and delays in capital allocations

A portfolio optimization problem for an investor who trades T-bills and a mean-reverting stock in the presence of proportional and convex transaction costs is considered. The proportional transaction cost represents a bid-ask spread, while the convex transaction cost is used to model delays in capital allocations. I utilize the historical bid-ask spread in US stock market and assume that the stock reverts on yearly basis, while an investor follows monthly changes in the stock price. It is found that proportional transaction cost has a relatively weak effect on the expected return and the Sharpe ratio of the investor's portfolio. Meantime, the presence of delays in capital allocations has a dramatic impact on the expected return and the Sharpe ratio of the investor's portfolio. I also find the robust optimal strategy in the presence of model uncertainty and show that the latter increases the effective risk aversion of the investor and makes her view the stock as more risky.     

The Information Content of Dividend Initiations and Firm Size: An Analysis Using Bid-Ask Spreads

The bid-ask spread of stock prices is examined for a sample of dividend initiating firms. The average percentage and dollar bid-ask spreads increase significantly on the day preceding the Wall Street Journal Index announcement date, possibly reflecting, on average, the market maker's anticipatory uncertainty. The day -1 increase in spread is inversely associated with firm size, an information environment proxy, after considering the simultaneous effects of dividend yield, returns variance, dollar trading volume and share price. The average percentage spread declines significantly on day 0 from its day -1 level and remains lower, on average, over a 365 day post-announcement period than 90 day pre-announcement levels. Similar results are obtained for dollar spread averages. The post-announcement percentage spread decline suggests a resolution of uncertainty, and is positively associated with the dividend yield. Dividend initiation announcements appear to reduce informational asymmetry.     

EMPIRICAL EVIDENCE ON THE IMPACT OF THE BID-ASK SPREAD ON THE CHARACTERISTICS OF CRSP DAILY RETURNS

It is widely recognized that Center for Research in Security Prices (CRSP) returns may differ from “true” returns because of the bid-ask effect. Using a large sample of New York Stock Exchange and American Stock Exchange securities, I confirm a discernible bid-ask effect, the magnitude and importance of which decrease with the security's price level (increase with the spread). I find volatility estimates using CRSP returns to be greater than those based on quote returns. However, market model properties, such as β and R², are generally unaffected. Bid-ask effects are clearly apparent in event studies, but because of certain offsetting effects commonly used test statistics remain unaffected. Low-priced stocks (below $2.00) do not conform to these patterns. Finally, the evidence raises the possibility that the existing literature on filter rule tests may underestimate the bid-ask spread component of transaction costs.     

WINNERS AND LOSERS ON NYSE: A RE-EXAMINATION USING DAILY CLOSING BID-ASK SPREADS

We study a sample of NYSE stocks that experienced a large one-day price change during 1992 and were reported as daily largest percentage gainers and largest percentage losers in the Wall Street Journal. The sample indicates significant reversals during the immediate post-announcement period. We test for market efficiency by using bid-ask spreads obtained from the transactions data for the days immediately after the announcement. The overall results indicate that the returns during the reversal period are less than the average bid-ask spread during the same time. We also find that major losers, firms with ?20 percent to ?50 percent event-date abnormal returns, experience price reversals generating returns that are significantly greater than the average bid-ask spread during that period. We interpret this result as consistent with the overreaction hypothesis. A test of a trading rule to exploit this overreaction is not profitable, providing support for weak-form market efficiency.     

深市买卖价差逆向选择成分的估算与分析

本文以深市150家上市公司为样本，估算买卖价差逆向选择成分，研究逆向选择成分与公司特征之间的关系，并探讨其日内变化模式。研究发现信息不对称对深市买卖价差的贡献度为39％。公司规模越大，其股票的逆向选择成分越小；逆向选择成分随着交易量水平的上升而降低；高价股的逆向选择成分比低价股低。总体而言，逆向选择成分在早市呈现“倒U”型，在午市呈现“L”型。逆向选择成分与公司特征之问的关系及逆向选择成分的日内变动模式的实证分析结果，符合信息不对称与公司特征之问的逻辑关系及信息不对称的日内变动模式。     

PERFORMANCE OF STOLL's SPREAD COMPONENT ESTIMATOR: EVIDENCE FROM SIMULATIONS,TIME-SERIES,AND CROSS-SECTIONAL DATA

Stoll (1989) introduces an intuitive procedure to estimate the basic components of the bid-ask spread (order-processing cost, inventory cost, and adverse-selection cost). He also provides reasonable estimates of the magnitudes of the order-processing, inventory, and adverse-selection costs of making markets for a large cross-section of NASDAQ/NMS stocks. Empirical applications of Stoll's model produce widely different estimates of the bid-ask spread components. We derive the sampling properties of Stoll's estimator of the realized bid-ask spread, i.e., the sum of the order-processing and inventory components. We test Stoll's model in simulations, using the ideal conditions implied by the model. We conclude that noise in serial covariance estimates causes estimates of the realized spread to be severely biased and highly unreliable in short time-series and small cross-sectional samples.     

Stock price synchronicity and liquidity

We argue and provide evidence that stock price synchronicity affects stock liquidity. Under the relative synchronicity hypothesis, higher return co-movement (i.e., higher systematic volatility relative to total volatility) improves liquidity. Under the absolute synchronicity hypothesis, stocks with higher systematic volatility or beta are more liquid. Our results support both hypotheses. We find all three illiquidity measures (effective proportional bid-ask spread, price impact measure, and Amihud's illiquidity measure) are negatively related to stock return co-movement and systematic volatility. Our analysis also shows that larger industry-wide component in returns improves liquidity. We find that improvement in liquidity following additions to the S&P 500 Index is related to the stock's increase in return co-movement.     

金融期货最小价格变化单位的市场影响与最优水平

最小价格变化单位是买卖价差的底线，设置过高会人为地提高买卖价差的水平，增加交易费用；过低又会降低市场深度，增加交易谈判成本，影响交易效率。对最优价格升降档位的设定，要综合考虑精度要求、合约乘数、交易谈判成本和实际买卖价差水平等因素；而以实际买卖价差的底线作为最小价格升降档位，能较好地避免人为抬高买卖价差的情况出现。     

AN IMPLICIT MEASURE OF THE EFFECTIVE BID-ASK SPREAD: A NOTE

We extend Roll's study of the effective bid-ask spread in an efficient market environment by allowing for serially correlated order arrival and quote behavior. This extension results in a more general effective bid-ask spread measure, which precludes imaginary spreads and includes Roll's measure as a special case when the serial correlation is zero. This new measure is related to the length of the measurement interval due to the serial correlation, and thus has the potential to explain the previously observed differential between weekly and daily derived spreads.     

Dealership market: Market-making with inventory

This study considers the problem of a price-setting monopolistic market-maker in a dealership market where the stochastic demand and supply are depicted by price-dependent Poisson processes [following Garman (1976)]. The crux of the analysis is the dependence of the bid-ask prices on the market-maker's stock inventory position. We derive the optimal policy and its characteristics and compare it to Garman's. The results are shown to be consistent with some conjectures and observed phenomena, like the existence of a ‘preferred’ inventory position and the downward monotonicity of the bid-ask prices. For linear demand and supply functions we derive the behavior of the bid-ask spread and show that the transaction-to-transaction price behavior is intertemporally dependent. However, we prove that it is impossible to make a profit on this price dependence by trading against the market-maker. Thus, in this situation, serially dependent price-changes are consistent with the market efficiency hypothesis.     

PROBABILITY OF PRICE REVERSAL AND RELATIVE NOISE IN STOCK AND OPTION MARKETS

In this paper we take a new approach to the study of the interrelation between stock and option markets by extending Stoll's (1989) model of cost components of the bid-ask spread to include an error component in prices. Building upon Stoll's estimates of the probability of price reversals, we determine which of the option or stock markets carries more noise. The empirical results indicate that option markets are noisier than stock markets. Such findings are consistent with the view that option markets serve as a testing ground for noisy new information because of their comparative advantage regarding transaction costs, liquidity, and potential leverage.     

Inferring the Components of the Bid-Ask Spread: Theory and Empirical Tests

The relation between the square of the quoted bid-ask spread and two serial covariances—the serial covariance of transaction returns and the serial covariance of quoted returns—is modeled as a function of the probability of a price reversal, π, and the magnitude of a price change, ?, where ? is stated as a fraction of the quoted spread. Different models of the spread are contrasted in terms of the parameters, π and ?. Using data on the transaction prices and price quotations for NASDAQ/NMS stocks, π and ? are estimated and the relative importance of the components of the quoted spread—adverse information costs, order processing costs, and inventory holding costs—is determined.     

A call auction's impact on price formation and order routing: Evidence from the NASDAQ stock market

Electronic call auctions are used globally to open and close equity market trading; as such, they are a critically important facility that needs to be better understood. The paper focuses on the impact NASDAQ's calls (introduced in 2004) have had on bid-ask spreads, price volatility, and order routing in the continuous market that follows daily openings and which precedes daily closings. NASDAQ's closing call has significantly reduced both spreads and volatility for all market capitalization groups. Its opening call similarly reduced spreads, while a generally similar, though somewhat weaker, pattern of volatility reduction was realized. Although the pattern of trading volume has, for the most part, not been significantly affected, our findings, comprehensively viewed, suggest that the calls have had a positive spillover effect on the dynamic behavior of price formation in NASDAQ's continuous market.     

Bid-ask Spreads, Trading Volume and Volatility: Intra-day Evidence from the London Stock Exchange

This paper examines intra-day variations in the bid-ask spread, volatility and volume for stocks traded on the London Stock Exchange. The data set used consists of quote and transactions data for a large sample of 835 stocks traded during the first quarter of 1991. The focus of the study is twofold; first, is to document a number of stylized facts regarding the intra-day behaviour of spread, trading volume, volatility etc. Second, the paper tests some predictions of two theoretical models of intra-day behaviour: the Admati and Pfleiderer and the Brock and Kleidon models. In addition, the paper also studies qualitatively the intra-day behaviour of several variables of interest including volume per transaction, transactions per fifteen-minute interval and spreads/trading volume for stocks of differing liquidity. The results suggest that the bid-ask spread is wide at the open, constant through the day and rises slightly at the close. Trading volume, in contrast is not highest at the open and the close. Volatility, based on the mid-point of the inside spread, shows a U-shaped pattern. Volume per transaction, in contrast, is fairly constant throughout the day. Further, the intra-day trading volume pattern differs for liquid and illiquid stocks. The results provide mixed support for current theoretical models of intra-day behaviour of spread, volume and volatility on the London Stock Exchange     

BID-ASK SPREAD COMPONENTS IN AN ORDER-DRIVEN ENVIRONMENT

The purpose of this study is to extend the bid-ask spread decomposition literature into the order-driven environment. The use of electronic limit order books, combined with order-driven market making, has been increasing rapidly in recent years because of improvements in information technology and financial market deregulation. To date, reported bid-ask spread decompositions rely almost exclusively on quote-driven or hybrid systems. This study provides bid-ask spread component estimates from one of the world's largest order-driven markets, the Stock Exchange of Hong Kong. Based on a sample of over six million observations, we estimate a median adverse selection component of 33 percent and a median order processing component of 45 percent of the spread. Dollar-volume-based decile portfolios show significant cross-sectional variation for adverse selection costs but insignificant variation for order processing costs. Finally, order persistence is consistently positive for all deciles and displays a direct relation with the level of trading activity.     

Regulation and stock market quality: The impact of MiFID II provision on research unbundling

This paper investigates the effects produced by the unbundling of analyst research costs required by MiFID II on market quality, as measured by stock liquidity and price efficiency. We find that the payment of an explicit price for research is associated with a reduction in analyst coverage in the EU. Unexpectedly, the reduction is stronger for large-cap stocks. For mid- and large-cap stocks analyst coverage in the EU is still greater than in the US. The reduction in analyst coverage observed in the EU is part of a downward trend that initiated prior to MiFID II and contributes to close the gap between the two regions. We also find no change in the bid-ask spread for small-, mid- and large-cap stocks, and a slight increase for micro-cap stocks. We observe no significant change in price efficiency. Taken together our findings seem to suggest that there was an overproduction of research in Europe with the previous regulatory regime. However, the growth of passive management and index funds may also explain the observed decrease in coverage.     

Information Effects on the Bid-Ask Spread

An individual who chooses to serve as a market-maker is assumed to optimize his position by setting a bid-ask spread which maximizes the difference between expected revenues received from liquidity-motivated traders and expected losses to information-motivated traders. By characterizing the cost of supplying quotes, as writing a put and a call option to an information-motivated trader, it is shown that the bid-ask spread is a positive function of the price level and return variance, a negative function of measures of market activity, depth, and continuity, and negatively correlated with the degree of competition. Thus, the theory of information effects on the bid-ask spread proposed in this paper is consistent with the empirical literature.