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J. Japanese Int. Economies 22 (2008) 417–438

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Stock splits, liquidity, and information asymmetry—An empirical study on Tokyo Stock Exchange

Fang Guo a, Kaiguo Zhou b,∗, Jinghan Cai c

a Department of Marketing Operation, Top Glory International Holdings Limited, Top Glory Tower,262 Gloucester Road, Causeway Bay, Hong Kong, China

b Department of Finance, Lingnan College, Sun Yat-sen University, Guangzhou 510275, Chinac Research Institute, Shenzhen Stock Exchange, Futian District, Hongli (west) Road, Shangbu Industrial Zone, Bldg. 10,

Shenzhen 518028, China

Received 27 June 2007; revised 20 January 2008

Available online 12 February 2008

Guo, Fang, Zhou, Kaiguo, and Cai, Jinghan—Stock splits, liquidity, and information asymmetry—Anempirical study on Tokyo Stock Exchange

This paper comprehensively studies the effects of stock splits on the market characteristics of the stocksand also tries to give an explanation for the results referring to the existing hypotheses and previous empiri-cal results. We investigate the trading activity, liquidity, information asymmetry, and the investors’ behaviorchanges around the stock splits. We find that the stock splits tend to increase the trading activity, to en-hance the market liquidity, to reduce the information asymmetry, and to lower the probability of informedtrading. Several main existing explanations—signaling hypothesis, trading range hypothesis, and tick sizehypothesis—are largely supported by our empirical findings. J. Japanese Int. Economies 22 (3) (2008) 417–438. Department of Marketing Operation, Top Glory International Holdings Limited, Top Glory Tower, 262Gloucester Road, Causeway Bay, Hong Kong, China; Department of Finance, Lingnan College, Sun Yat-sen University, Guangzhou 510275, China; Research Institute, Shenzhen Stock Exchange, Futian District,Hongli (west) Road, Shangbu Industrial Zone, Bldg. 10, Shenzhen 518028, China.© 2008 Elsevier Inc. All rights reserved.

JEL classification: G12; G14; G32

Keywords: Stock splits; Liquidity; Information asymmetry; Tokyo Stock Exchange

* Corresponding author. Fax: +86 20 84114823.E-mail addresses: [email protected] (F. Guo), [email protected] (K. Zhou), [email protected] (J. Cai).

0889-1583/$ – see front matter © 2008 Elsevier Inc. All rights reserved.doi:10.1016/j.jjie.2008.01.002

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http://dx.doi.org/10.1016/j.jjie.2008.01.002

418 F. Guo et al. / J. Japanese Int. Economies 22 (2008) 417–438

1. Introduction

The event of stock split is a very popular phenomenon in the equity market, yet it is also one ofthe least understood corporate events. At first glance the split only changes the number of sharesoutstanding of a firm, leaving the fundamentals unchanged. Since it will not affect the intrinsicvalue, the cash flow, or the relative strength of any interested party of the firm, there should be nomotivation for the firm to split its shares. Even if the firm does split its stocks, there should be nosignificant change to the firm’s value or trading characteristics. Why, then, does a rational firmbother to take action to increase its outstanding shares when doing so will incur costs withoutbringing any profit? The question needs further study to uncover more evidence on the effects ofstock splits.

Up to now, there are three main hypotheses proposed to explain the effects of stock splits: thesignaling hypothesis, the trading range hypothesis, and the tick size hypothesis. The signalinghypothesis states that the management intends to transmit good information about the compa-ny’s future performance to the public. The trading range hypothesis argues that the managementwould like to bring the stock price into a certain optimal range and hence the stability and liquid-ity of the stock will improve after a split due to an increase in the ownership base. The tick sizehypothesis regards stock split as a method for keeping the tick size relative to the stock price atan optimal level.

Most of the previous studies on stock split are conducted in the US markets, while little evi-dence has been provided from Asian markets. The Tokyo Stock Exchange (TSE) is the biggeststock market in Asia and attracts worldwide attention. Meanwhile, stock splits are very commonin this market. Therefore, it is necessary to conduct a study on TSE and to provide more evidenceon the effects of stock splits. The motivation of this study is to conduct a comprehensive empir-ical study on the trading characteristics and changes in traders’ behavior around stock splits byinvestigating cases from the Tokyo Stock Exchange. This paper contributes to the literature byproviding non-US evidence. With the empirical results, we try to explain the effects with respectto changes in investors’ behavior and to link the results to the existing hypotheses in order toverify whether they are supported or not. The second, also the greatest, contribution of this paperis to harmonize the three existing hypotheses with the empirical evidence from TSE.

We will focus on three aspects of effects induced by stock split: trading activity, liquidity, andinformation asymmetry. Our empirical results are as follows.

First, the results show that both the number of quotations and the number of trades increasesignificantly after stock splits, while the trade size decreases significantly and there is no signi-ficant change in the daily trading volume. Meanwhile, the quoted depth decreases significantly.The findings imply that the stocks are traded more actively only on small trades after stock splits.

Second, the results about liquidity show that the absolute quoted spread, the absolute effectivespread, the relative quoted spread and the relative effective spread all decrease significantly afterstock splits, while the quoted depths at both sides decrease significantly. When the spread anddepth are combined into the quality index to measure the liquidity change, it is shown that theliquidity is enhanced after stock splits.

Next, the information asymmetry is studied. The results show that the adverse-selection com-ponent decreases significantly after stock splits, which supports the trading range hypothesis,which predicts that the reduction in price due to the splits attracts more small investors.

Finally, although both the informed and the uninformed traders increase significantly afterstock splits, the probability of informed trading (PIN) decreases, because compared with the in-formed traders, more uninformed traders join to trade after stock split. Therefore, the increase in

F. Guo et al. / J. Japanese Int. Economies 22 (2008) 417–438 419

the information asymmetry caused by the informed trades are offset or overwhelmed by thedecreasing effects caused by the uninformed trades. As the information asymmetry and theprobability to meet the informed traders are reduced after splits, the market makers or liquidityproviders are facing less risk. This decreased risk is reflected on the decrease in bid–ask spread.So all the empirical results are consistent and can be explained soundly from the perspective ofthe investors’ behavior change.

These empirical findings provide strong evidence for the effects of stock splits on Tokyo StockExchange. The findings indicate that the events really affect the stocks’ quality. Moreover, it isthe change in the investors’ behaviors that causes the change in the market characteristics of thestocks. These findings also prove that the firms may split their stocks due to multi-faceted reasonsbecause all existent hypotheses are supported by the empirical results in this study.

The rest of this paper is organized as follows. Section 2 is the literature review. Section 3describes the data and methods adopted in this study. The empirical results and explanations arepresented in Section 4. Discussion and conclusions are given in Section 5.

2. Literature review

Fama et al. (1969) take advantage of the opportunity of stock split to study the market effi-ciency on the adjustment of stock price to new information. It is regarded as the first research tostudy the effects of stock splits. Since then, a large number of researchers have contributed theirefforts to this study. There are two main schools of thought on this topic. One is the motivation ofthe management to split the stocks. The other concentrates on the effects of stock split on marketcharacteristics.

There are mainly three explanations on firms’ motivation for splitting stocks: signaling hy-pothesis, trading range hypothesis (or liquidity hypothesis), and tick size hypothesis. The sig-naling hypothesis is formed after observing the abnormal announcement returns following stocksplit. It says that the management is sending a signal to the market that the firm is expected toenjoy an income increase or that the firm’s value is underestimated. The trading range hypothesisargues that the manager intends to bring the stock price to an optimal range by splitting stocksand consequently to increase the stock’s market liquidity. The tick size hypothesis states that themanager tends to split its stocks so that the minimum tick size is optimal relative to the stockprice.

The effects of stock split on market characteristics mainly focus on the abnormal return andliquidity. Many studies have found that there are positive excess returns around announcementday and effective day and that the trading volume increases significantly. These findings supportthe signaling hypothesis. However, some studies have observed that the bid–ask spreads increasesignificantly, which contradicts the liquidity enhancement hypothesis.

2.1. Signaling hypothesis

The empirical studies on stock splits by Fama et al. (1969), Bar-Yosef and Brown (1977), andCharest (1978) find abnormal returns around the announcement day, which supports the signalinghypothesis. According to the signaling model of Spence (1973), Ross (1977), Leland and Pyle(1977) and Bhattacharya (1979), the financial decisions of the management convey informationabout the firm value. This hypothesis assumes that the information between managers and in-vestors are asymmetric and by splitting stocks the managers intend to convey good information


to investors. This hypothesis also states that the managers are confident in their company’s futureearnings and will push the stock price upward.

Grinblatt et al. (1984) study the valuation effects of stock splits and stock dividends. Theyconclude that some of the information content of stock split and stock dividend appears to beassociated with firms’ future cash flows or their future earnings or their equity values. Lamoureuxand Poon (1987) study the abnormal return and trading volume after the stock split. Their findingsof the positive cumulative abnormal return and the increase in raw trading volume after theannouncement also provide evidence to support the signaling hypothesis.

To support the signaling hypothesis, McNichols and Dravid (1990) test whether the stockdividends and splits convey information about company’s future earnings and also test whetherthe split factor acts as a signal. They use the analysts’ earnings forecast error, measured as thepercentage difference between the after-split annual earnings reported and the median analysts’before-split earnings forecast, as a proxy for management’s private information. The result showsthat when pre-split stock price and market value of equity are controlled, the correlation betweensplit factors and earnings forecast errors is significant. This suggests that the choice of split factorcontains the management’s private information about future earnings. This result also supportsthe signaling hypothesis.

Building their theory on the assumption that trading is costly, Brennan and Copeland (1988)develop a two-period signaling model of stock splits to explain the abnormal return. They con-clude that management can convey private information about the firm’s prospects to investorsthrough a stock split announcement because the cost of trading depends on the stock price.Brennan and Hughes (1991), Ikenberry et al. (1996), and Conroy and Harris (1999) also findevidences to support the signaling hypothesis.

Though the signaling hypothesis can be supported by empirical studies, it remains a puzzlewhy companies split their stocks. There shall be no price limit on a stock, and other devices (suchas dividend) can also be adopted to issue the good signal. Furthermore, empirical research hasdocumented negative effects after splits, such as a larger relative bid–ask spread and a higherlevel of information asymmetry. In addition, the signaling hypothesis cannot explain why excessreturns are also observed around the ex-split date since the ex-split date is predictable followingthe split announcement and there should be no information content on the ex-date. So researchersprovide other explanations for stock split. Grinblatt et al. (1984), Maloney and Mulherin (1992)explain the excess returns from the viewpoint of microstructure and suggest the liquidity-basedexplanation for stock splits, and this induces the second hypothesis.

2.2. Trading range hypothesis

Copeland (1979) argues that firms prefer to keep the prices of their stocks within a certainrange. He explains that keeping a certain price range can attract a specific kind of clientele ordisperse the ownership of the company. The kind of clientele attracted by the lower prices broughtabout after a stock split is usually considered to be uninformed or small investors. Baker andGallagher (1980) make a survey on managements’ views on stock split. The survey reveals thatthe majority of a firm’s financial officers believe that the stock split is a good device to bringthe stock price to an optimal trading range. A lower stock price will attract investors and thenenhance the ownership base. Evidence has been found to support this hypothesis. Lamoureuxand Poon (1987) find that the daily number of transactions along with the raw trading volume ofshares increases following splits. Kryzanowski and Zhang (1996) make use of the trading valueto measure small and large traders and find that small traders trade more frequently after stock


split and that the trade direction changes significantly from sell to buy. Angel et al. (1997), Desaiet al. (1998), and Schultz (2000) also find evidence of changes in trading behavior after stocksplits.

But why would a company want to attract small or uninformed traders to invest in its stocks?One of the most popular explanations is that the enlarged investor base will increase the liquidityof the stock and thereby reduce the trading cost for the investors. Therefore, the motivation of themanagers to split stocks is to enhance liquidity. From the viewpoint of liquidity, the trading rangehypothesis is also called “liquidity hypothesis.” Merton (1987) sets up a model of capital marketequilibrium with incomplete information. The model indicates that an increase in the relative sizeof the firm’s investor base will reduce the firm’s cost of capital and increase the market value ofthe firm. It is also stated that managers have incentives to expand the firm’s investor base. Thistheory can explain the reaction of stock prices to stock splits. Because lower prices attract smallinvestors to take part in buying or selling stocks after a split, the liquidity of the stock increases.Small traders are also considered as noise traders in contrast to informed traders. Black (1986)states that noise trading is essential to the existence of liquid markets, and the more noise tradesthere are, the more liquid the markets will be.

There are many kinds of measures of liquidity, but the most frequently used ones include trad-ing volume, bid–ask spread, depth, and number of trades. The proxies can be classified into twocategories: indicators of friction and activity, which are the two dimensions of liquidity. Frictionis defined by Demsetz (1968), Grossman and Miller (1988), Stoll (2000) as the price continuityfor immediacy. Activity reflects the extent of trading. The bid–ask spread can be categorized asa friction measure. In contrast, the depth, volume, number of trades and transaction value canbe classified as activity measures. Using different proxies for liquidity, the empirical results onthe impact of stock splits point to different conclusions. Some support the liquidity enhancinghypothesis, while others contradict it.

Copeland (1979) takes both trading volume and bid–ask spread as measures of liquidity instudying the 162 OTC firms for the period 1968–1976. The results show that the trading volumeis proportionately lower after split while the post-split bid–ask spread increases significantly asa percentage of the stock price, meaning that the liquidity of the stock decreases after split. ButMurray (1985) finds no evidence of a change in percentage spread relative to a control groupby studying 100 OTC splitting firms during the period 1972–1976. Lakonishok and Lev (1987)take the monthly shares traded relative to the shares outstanding as the measure of a stock’smarketability and find that the result does not support a decrease in marketability. Lamoureuxand Poon (1987) study the stock’s factor-adjusted trading volume relative to the market’s trad-ing volume after stock split, and the result shows that 87 sample stocks’ market-adjusted andfactor-adjusted trading volume decreased significantly while that of 27 sample stocks showed asignificant increase. They conclude that the value of shares traded fell following the ex-split day.

Conroy et al. (1990) also take absolute spreads and percentage spreads as measures of liq-uidity, but they employ high-quality inside quotes, which capture the lowest ask and highestbid that would have been available to an investor. Their empirical results show that liquid-ity decreases after stock splits as measured by the percentage bid–ask spread. Although theabsolute spread decreases after split, the drop in price is sufficient to offset the decrease in ab-solute spread and leads to an increase in the percentage spread. The conflict in the results ofliquidity change after split mainly originates from the difference in measures adopted by theresearchers.


2.3. Tick size hypothesis

This hypothesis suggests that stock splits will create an optimal tick size for stocks, and thatthis optimal tick size will attract liquidity providers to take part in transactions. The liquidityproviders are regarded as uninformed traders who can gain from supplying liquidity via limitorders.

Angel (1997) uses the minimum price variation to explain the price change around the stocksplit. He states that the management tends to keep the tick size relative to the stock price at anoptimal level. If the relative tick size is larger than optimal, the company will allow the long-termupward trend of stock prices to reduce it to the desired level. When the relative tick size is toosmall, the stock split can be adopted to increase it back to the optimal level. As Harris (1991)notes, tick size cannot be zero for the reason that the tick simplifies traders’ information setsand reduces time spent on bargaining and the potential for costly errors. Also. the nonzero tickenforces time and price priority in a limit order book, and provides an incentive for investors toprovide liquidity with limit orders. Furthermore, the tick also provides an incentive for dealersto make market. However, the enlarged tick also increases the trading cost and offsets the liq-uidity gains from dealers’ perspective. The optimal tick is the trade-off between the benefits of anonzero tick and the cost that a tick imposes.

By combining the Merton’s (1987) model of an incomplete information capital market withAmihud and Mendelson’s (1986) finding that higher bid–ask spreads are associated with higherrates of return, Angel (1997) constructs a model in which the increase in the number of investorswho know about a stock tends to increase the stock price while a higher transaction cost due tothe increase of tick size depresses the stock price. The solution to this model is that the optimalrelative tick size can balance these effects. The result shows that the tick size can explain partiallywhy stock price levels differ across countries. Since the rule on tick size varies across countries,the optimal trading range varies accordingly. However, the relative tick size is comparable fromcountry to country.

After Angel (1997), the results of some other researchers directly or indirectly support An-gel’s (1997) conclusion that the wider percentage bid–ask spread stimulates brokers to promotethe stock. Schultz (2000) provides evidence that according to measures of percentage effectivespreads market making is more profitable following splits. Moreover, the increase in the numberof small buy orders following splits proves the traditional explanation that the shareholder baseof stock increases after splits. Some other studies such as Lamoureux and Poon (1987), Maloneyand Mulherin (1992), and Angel et al. (1997) show evidence that the number of shareholdersincreases after splits, which supports Angel’s (1997) argument that a large relative tick size givesbrokers more incentives to promote the stock.

2.4. Information asymmetry argument

One of the arguments for the reason that companies split their stocks, though it may not beregarded as a hypothesis, is the reduction of information asymmetry. Grinblatt et al. (1984) arguethat managers use stock splits or stock dividends to convey good information to the market orjust call attention to the firm to trigger reassessments of the firm’s future cash flows by marketanalysts. The consequence of the information-leakage or attention-attraction will be the reductionof the information asymmetry existing between the managers and investors.

But does more information-leakage result in the reduction of information asymmetry? Desai etal. (1998) argue that the change in trading activity would affect the adverse-selection component


of the bid–ask spread. The increase in noise trading will reduce the adverse-selection component,while an increase in informed trading will increase this component. If both types of tradersincrease, the effects on the adverse-selection component will be complex and unpredictable. Theyadopt the method proposed by George et al. (1991) to decompose the total spread into the order-processing and adverse-selection components. They find that the adverse-selection componentincreased by 0.17 or 22% following splits and thus conclude that the information asymmetry isnot reduced after splits. Actually, their finding implies that informed trading increases. Thus, itis not clear whether the information environment of the firm following a split is characterized byhigher or lower information asymmetry before the behavior of uninformed traders is investigated.But at least the technique of decomposing the spread is a method to test whether the informationasymmetry does change or not.

The decomposition of the bid–ask spread can only give information on the change of adverse-selection component after splits. As to the change in composition of the trading population, it isnot so easy to give a conclusion. With this intention of trying to discover trading activity, but notfor the event of splits, researchers developed a microstructure model used to calculate the ratesof informed and uninformed trading, and the probability of information events. This method iscommonly called PIN value calculation.

Easley et al. (1996) develop an approach using the trading flow information to infer thedifference in information content between trading locales. This approach is used to test thecream-skimming versus competition issue. Easley et al. (2001) use this method to test alterna-tive hypotheses concerning the stock splits. Their model is an extension of the model of Easleyet al. (1996) and is used to estimate the underlying parameters that define trading activity. Themain parameters are the rates of informed and uninformed trading, the probability of informa-tion events, and the propensity to execute trading strategies using limit orders. As they state,when analyzing stock splits using the trading data will sacrifice some of the non-trade relatedimplications of the explaining hypotheses, because any signaling-related effects of splits may beimmediately reflected in prices, and thus would not be reflected in trades. They find that bothuninformed and informed trading activities increase after the split and there is a small decreasein the percentage of informed trades or PIN.

The model proposed by Easley et al. (2001) is based on the quote-driven market in whichthere are more than one market-makers participating in competition. But this model can alsobe adopted in the order-driven market in which liquidity is provided by the traders who submitthe limit-orders and the trader plays the role of market-maker, as in the quote-driven market.Moreover, the competition on price also exists between traders. Empirical research has beenconducted on the latter market. Ahn et al. (2005) adopt this method in studying the event ofminimum trading unit (MTU) change on the Tokyo Stock Exchange which is an order-drivenmarket.

3. Data and methodology

3.1. Data

The basic sample is comprised of all Tokyo Stock Exchange (TSE) common stocks that havesplit with a factor greater than 1.5 from January 1996 to December 2005 and that have a priceless than JP Yen 30,000 before split. We do not include the stocks with split factor of less than1.5 because such cases are similar to stock dividends, which are not our study object. Besides,we exclude the stocks with price over JP Yen 30,000 because the extremely high price would


distort our later results, especially on relative spreads. The split sample is provided by the TSEand we confirm the event by checking with the corresponding splits data from the BloombergNews Service and eliminate 10 firms due to the discrepancy in announcement date, effective dateor split factor. In order to avoid the effects of the previous split on the consequent split of thesame stocks, 3 more stocks are deleted from the sample because the interval between the stock’stwo splits is less than 8 calendar months. There remain 138 stock splits in our final sample.The corresponding tick data are obtained from the Nikkei Economic Electronic Database System(NEEDs).

3.2. Estimation windows

In a typical event study the pre-event period is usually set prior to the announcement day,while post-event period begins on some spot after the effective day. In our case, the pre-splitwindow is [−69,−10] trading days prior to the split announcement (see Conroy et al., 1990) inorder to avoid other events such as stock dividends and mergers contaminating the effects of thestock splits. Correspondingly, the post-split period is [10, 69] trading days after the effective day.However, we adopt a 120-day window in PIN estimation.

3.3. Definition of measures

3.3.1. Bid–ask spreadIn this study we adopt four types of bid–ask spreads: absolute quoted spread, absolute effective

spread, relative quoted spread and relative effective spread. Absolute quoted spread is defined asthe dollar difference between the ask and bid. Absolute effective spread is defined as twice theabsolute difference between the trade price (Pt ) and the quote midpoint (Mt).1 The relativequoted spread is the absolute quoted spread scaled by the quote midpoint. The relative effectivespread is the absolute effective spread scaled by the transaction price.

(1)Absolute Quoted Spread = Ask − Bid

(2)Absolute Effective Spread = |Pt − Mt | ∗ 2

(3)Relative Quoted Spread = (Absolute Quoted Spread)/Mt

(4)Relative Effective Spread = (Absolute Effective Spread)/Pt

3.3.2. Quality indexThe quoted depth is also adopted in this study as a measure of liquidity. The spread and depth

are two dimensions of liquidity. The spread measures the price dimension of liquidity, while thedepth measures the quantity dimension of liquidity. In order to integrate the two dimensions intoone, we adopt the quality index (QI), proposed by Gray et al. (2003), to measure the marketquality. A larger quality index means higher liquidity. The quality index is calculated as follows:

(5)QIt = (depth_at_bidt + depth_at_askt )/2

relative_quoted_spreadt × split_adjustment

1 In a pure order matching system in which trades should always go off at the bid or the ask price. However, on theTSE, market orders are allowed to cross each other. Therefore, it is possible that a market order is executed inside thespread. That is why we introduce both absolute quoted spread and absolute effective spread. See also Ahn et al. (2007).


3.3.3. Decomposition of the bid–ask spreadIn this paper we adopt Glosten and Harris (1988) model to decompose the spread into two

components.2 The first one is the transitory component which is to cover the inventory costs,clearing fees, and/or monopoly profits that are required of the market-makers. The second one iscalled adverse-selection component which is an additional widening of the spread to compensatethe loss aroused from the market-makers’ trading with informed traders. Although the modelis based on the market-makers, their methodology can also be adopted in a pure order-drivenmarket. In fact, each limit-order trader in an order-driven market plays the role of market makeras in a quote-driven market.

Here we briefly describe the two-component asymmetric information spread model. Thechange in transaction price at time t is denoted as Dt = Pt − Pt−1, where Pt indicates thetransaction price at time t , and Pt−1 indicates the previous transaction’s price. Qt is definedas the buy–sell indicator variable for the transaction. We let Qt = +1 if the transaction isbuyer initiated and −1 if the trade is seller initiated. The share volume of trade at time t isdenoted as Vt . α is the transitory spread component, β is the adverse-selection component, andμt is the error term. With the trading data mentioned above, the following equation is used toestimate the transitory component or order-processing component and adverse-selection compo-nent.

(6)Dt = α(Qt − Qt−1) + βQtVt + μt

We use Generalized Method of Moments (GMM) to estimate the parameters of Eq. (6) be-cause it imposes very weak distribution assumptions. This is especially important when the errorterm includes rounding errors due to discreteness of stock prices (see Ahn et al., 2002).

To facilitate the estimation, we adopt the stocks that have trading data for at least 20 validtrading days. A valid trading day must have no less than five valid transactions. When countingthe valid transactions, we exclude the opening and closing trades for the morning and afternoonsessions, and the transactions against special quotes as well.

3.3.4. Probability of informed tradingEasley et al. (1996) develop a method for estimating the probability of informed trading (PIN).

In this model, the informed and uninformed investors trade a single risky asset with the riskneutral market maker, and the price of the asset is set as equal to the expected value of the asset.The information events happen prior to the beginning of any trading day and they are thought tobe independently distributed and to occur with probability α. This information event is bad newswith probability δ, and good news with probability of 1 − δ. Trades arrive according to a Poissonprocess, with uninformed trades arriving at the rate of ε, and informed trades arriving at the rateof μ. All of these arrival processes are assumed to be independent.

According to the results of Easley et al. (1996), the PIN is defined as:

(7)PIN(t) = μ(1 − Pn(t))

μ(1 − Pn(t)) + 2ε

2 There are two classes of statistical models. The first one relies on the serial covariance properties of the observedtransaction prices (see Roll, 1984; Lin et al., 1995; and Huang and Stoll, 1997). And the second class is based on thetrade initiation indicator variables (see Glosten and Harris, 1988; Madhavan and Smidt, 1991). As the trade direction isclearly indicated in the dataset from the NEEDs, the trade indicator model is more appropriate in this study.


Where Pn(t) represents the probability of no information event happening at time t . If theparameters of θ = (α, δ, ε,μ) are known, the PIN can be easily calculated.

The parameters can be estimated using the MLE method from the structural model, whichextracts information on the parameters from the observable number of buys and sells. Thoughthe Poisson processes followed by the buys and sells are not known, the trading data reflect theinformation structure: more buy orders on the days with good news; more sell orders on the dayswith bad news; and fewer orders on the days with no news. Thus, the data on buys and sells (B,S)

will be enough to estimate the order arrival rates. Weighting the likelihood of the observed orderswith the probabilities of each type of day occurring (1 − α,αδ,α(1 − δ)), we get the likelihoodfunction as follows:

L((B,S) | θ) = (1 − α)e−εT (εT )B

B! e−εT (εT )S

S!+ αδe−εT (εT )B

B! e−(μ+ε)T [(μ + ε)T ]SS!

(8)+ α(1 − δ)e−(μ+ε)T [(μ + ε)T ]BB! e−εT (εT )S

S!Where T is the number of time intervals in each day. With the data of buys and sells (B,S),

the estimation of the arrival rates of informed and uninformed traders can be found.Trade data are taken from the NEEDs Daily Summary data. We take the 120 trading days as

the observation window. Again, we adopt the stocks that have trading data for at least 20 validtrading days, and have no less than five valid transactions in each trading day. Two out of the 138samples are dropped out because the results are not convergent.

4. Empirical results and explanations

4.1. Sample description

The distribution of the 138 samples across different years from 1996 to 2005 with differentfactors is listed in Table 1. The split occurred only once in 1996, and the number increased to 13in 1999. In the following 6 years it fluctuated from 13 times to 23 times. It reached its highestvalue of 41 times in 2004.

The factors adopted by the companies range from 1.5 to � 10. We can find the most frequentlyadopted factor by the companies is 2 and the number of samples reaches 85. Factors of 1.5 and 3are also what companies prefer to choose, and the total number of events is 47. These threefactors account for 95.7% of the total splits. There are 4 samples that split their stocks with afactor equal to or larger than 10.

Fig. 1 plots the time interval between the announcement day (AD) and effective day (ED) forthe 138 samples. The time intervals are classified into 7 groups: no more than 10 days, greaterthan 10 days but no more than 20 days, and so on. The longest interval is greater than 60 days.Most of the samples take splits in effect in less than 40 days after announcing them. The meanof the time interval is 32 days, and the median is 26 days. The minimum value is 7 days and themaximum is 117 days.

The Tokyo Stock Exchange classifies the listed companies into 9 industries. The frequencydistribution of stock splits by industry is presented in Table 2. It can be seen that splits happen inseven of the nine industries but concentrate on three industries (Manufacturing, Wholesale andRetail, and Service). It shows that the sample is basically representative for the firms on TSE.


Table 1Summary of splits

Year Factor

1.5 2 3 4 � 10 Total

1996 1 11999 6 7 132000 7 6 132001 8 9 172002 4 9 2 1 162003 3 10 1 142004 8 29 2 1 1 412005 4 15 3 1 23Total 40 85 7 2 4 138

This table presents the distribution of stock splits by year and by factor. The sample includes 138 events of stock splitsthat took place between March 1996 and December 2005 on Tokyo Stock Exchange. The factor ranges from 1.5 to largerthan 10.

This figure gives an illustration of the distribution of the time intervals between announcement day (AD) and effectiveday (ED) of the total 138-split sample.

Fig. 1. Frequency distribution of splits by time interval.

The stocks at Tokyo Stock Exchange are well-known for their high prices. Table 3 gives abasic description on the stock prices before and after the split. This description is based on theaverage closing trading price of the last two trading days before announcement day and theconsequent two trading days after effective day. The mean of the stock price is 535,307 JP Yenbefore the split announcement and 182,887 JP Yen after the split. The high stock price givessome explanation on the high absolute spread in the coming section. Also, we can observe fromTable 3 a large price drop around the stock split.


Table 2Industry distribution of the sample stocks

Industry No. of stocks

Construction 1Manufacturing 46Wholesale and retail 39Financial and insurance 6Real estate 10Transportation and communication 1Service 35Total 138

This table presents the frequency distribution of the studied sample by the indus-try that they are classified into. The Tokyo Stock Exchange divides stocks into 9main industries. The splits cover 7 of them.

Table 3Stock price description

Pre-split Post-split

Number of observations 138 138Mean 535,307 182,887Median 15,160 6850Standard deviation 1,485,538 370,169Maximum 10,300,000 2,300,000Minimum 462 16Upper quartile 75% 493,000 264,000Lower quartile 25% 4905 2510

This table presents basic description on the stock prices of the pre-split period and post-split period. This descriptionincludes the mean, median, maximum, minimum values of the stock price.

4.2. Announcement effects

We begin our empirical analysis with the transaction direction. As indicated in Fig. 1, there aretime intervals, large or small, between AD and ED, and the announcement effect will probablydisappear after the effective day, so we do not count the change after ED. Rather, we documentthe announcement effect in the 10 trading days after AD. Moreover, in the semi-strong form ofmarket efficiency the impact of the release of private information (good news) from the firm’smanagement to investors through a stock split should disappear quickly on the announcementday. It is not likely that the effect of signaling lasts over the window of [10, 69] after AD. So thesignaling hypothesis makes no judgment in the long window.

As the signaling hypothesis states, the management uses splits to convey good informationto the public. If this assumption is right, we can expect that more buying orders would appearbecause investors are motivated by good news. Different from other researchers’ methods thatadopt the abnormal return (AR) or cumulative abnormal return (CAR) as proof to support thesignaling hypothesis, we use the change in the ratio between transactions at bid and transactionsat ask to test this hypothesis. The result is presented in Table 4. The estimation period is 60 tradingdays before AD and the observation period is 10 trading days after AD. The ratio decreasessignificantly in the following 10 trading days after AD. This indicates a significant increase inthe number of transactions at ask compared to that of transactions at bid. Investors are more likely


Table 4Transaction direction change after AD

Relative day AD

Change (Log-diff.) Statistic p-value

+1 Mean −0.58 −12.88 0.00Median −0.56 −3066 0.00

+2 Mean −0.36 −8.4 0.00Median −0.33 −2792 0.00

+3 Mean −0.33 −7.11 0.00Median −0.32 −2778 0.00

+4 Mean −0.36 −7.48 0.00Median −0.33 −3030 0.00

+5 Mean −0.29 −5.8 0.00Median −0.27 −2497 0.00

+6 Mean −0.36 −6.87 0.00Median −0.28 −2820 0.00

+7 Mean −0.33 −7.15 0.00Median −0.32 −2814 0.00

+8 Mean −0.31 −6.48 0.00Median −0.31 −2735 0.00

+9 Mean −0.33 −6.82 0.00Median −0.31 −2774 0.00

+10 Mean −0.32 −5.57 0.00Median −0.38 −2497 0.00

This table presents the change on the ratio between the number of transaction at bid and the number of transaction at askduring 10 trading days after the announcement day (AD). The estimation window is [−69,−10] relative to AD, and thestudied period is [+1,+10] relative to AD. The percentage change of the ratio, the test statistic on mean or median, andthe p-value of corresponding test are given in the corresponding columns.

to buy stocks instead of selling them in the short run. Our empirical result gives direct support tothe signaling hypothesis.

4.3. Trading activity effects

To examine the trading activity effects of stock split, we use three measures on trades: thenumber of trades, trade size, and daily trading volume, as well as three measures on quotations:the number of quotations, the numbers of quotations at ask and at bid.

It is considered that the lower price of the stock after split will attract small traders to partici-pate in trading this stock and that small traders buy or sell at small amount in measure of sharesor values. Thus, there should be an increase in the number of trades and also in the number ofquotations while the trading size may not increase proportionally.

The results can be found in Tables 5 and 6. For each measure of the trading activities, themean and median during pre-split period and post-split period are presented in the second andthird column, respectively. As to the trade size and daily volume measures, the post-split numbersare based on the factor-adjustment.

Table 5 presents the quotation change. The mean of the daily number of quotes increasessignificantly from 655 during the pre-split period to 925 during the post-split period. There is a


Table 5The number of quotes

Full sample (N = 138) Pre Post t-value Sign-rank Log-diff.(p-value)

A. Daily number of quotesMean 654.87 925.05 8.55 0.388 (0.00)Median 430.43 685.73 3416 0.384 (0.00)

B. Bid quotationsMean 327.44 462.52 8.55 0.388 (0.00)Median 215.22 342.87 3416 0.384 (0.00)

C. Ask quotationsMean 327.43 462.43 8.54 0.388 (0.00)Median 215.22 342.87 3415 0.384 (0.00)

This table presents the cross-sectional means and medians of the average daily number of quotes, bids and asks. Thepre-split period (‘Pre’) is the [−69,−10] window relative to the announcement day (AD). The post-split period (‘Post’)is the [+10,+69] window relative to the effective day (ED). The opening and closing trades and the quotes before theopening trade or after the closing trade are excluded. The log-difference (percentage change) and p-value from t -tests(for mean) or sign-rank tests (for median) are reported in the last column.

38.8% increase in the daily quotation after stock splits on average. This increase is statisticallysignificant at 1% confidence level. The median changes from 430 to 686 and there is an increaseof 38.4%. The median test also shows this increase is significant at 1% level. The results showthat there are significant increases on both ask quotations and bid quotations after stock split.Just as expected, the numbers of quotations on ask side (327.43) and bid side (327.44) are almostequal during pre-split period. This situation does not change after stock split. The results frommedian numbers are highly consistent with the mean results. They confirm that stock splits donot affect the balance between the ask quotation and bid quotation. These results are consistentwith the trading range hypothesis because if a reduced price attracts more uninformed traders’participation, it tends to proportionally appear on both buy and sell sides.

The changes in number of trades, trade size and trading volume are reported in Table 6. Themean of the daily number of trades increases significantly from 132 during the pre-split periodto 182 during the post-split period. In percentage, the increase is 41%. The increase is statis-tically significant at 1% level. The median changes from 69 during the pre-split period to 121during the post-split period with an increase by 42% and is also statistically significant at 1%level.

Will the increase in the number of trades be accompanied by an increase in trading volumeproportionally? The results of trade size and trading volume are reported in part B and part Crespectively. The trade size decreases from the mean of 575 shares during pre-split period to360 shares during post-split period, which is factor adjusted. The t -value is −21.28 and p-valueof the log-difference between pre-split and post-split values is less than 0.01, which shows thatthe change is statistically significant. The result is confirmed by the median test. The p-valueof log-difference of the medians is less than 0.01 which also shows that the median change isstatistically significant.

The results show that the trade size decreases significantly while the number of trades in-creases significantly. Then we may consider the result of trading volume. Part C of Table 6reports that there is no significant change in the daily trading volume after stock splits. The meandecreases from 85,513 shares to 84,508 shares after stock splits and the median decreases from


Table 6Number of trades, trade size and trading volume

Full sample (N = 138) Pre Post t-value Sign-rank Log-diff. p-valueLog-diff.

A. Number of tradesMean 132.44 182.18 7.48 0.409 0.00Median 69.62 121.67 3038 0.424 0.00

B. Trade sizes (factor adjusted)Mean 575.18 360.30 −21.28 −0.464 0.00Median 343.91 204.21 −4612 −0.454 0.00

C. Daily volume (factor adjusted)Mean 85,513 84,508 −0.75 −0.048 0.45Median 23,733 22,665 −179 −0.004 0.70

This table presents the means and medians of average daily number of trades, trade size and trading volume. The pre-split period (‘Pre’) is the [−69,−10] window relative to the announcement day (AD). The post-split period (‘Post’) is the[+10,+69] window relative to the effective day (ED). The trade size and daily trading volume for the post-split periodare factor adjusted, i.e., divided by the split factor. The opening, post-closing and closing contracts are excluded. Thelog-difference (percentage change) and p-value from t -tests (for mean) or sign-rank tests (for median) are reported inthe last two columns.

23,733 to 22,665. Neither the mean test nor the median test can reject the null hypothesis thatthere is no significant change between the trading volumes during pre-split and post-split periods.

Some researchers examine the trade direction change around splits. Kryzanowski and Zhang(1996) find that the trade direction switches significantly from sell to buy after the split ex-datefor all but large trades, where the change is in the opposite direction. We also investigate thetrade direction change after stock splits. The daily mean and median numbers of trades at askand at bid during the pre-split period and post-split period are presented in Table 7. The resultscan reveal some information on the traders’ behavior change. It is found that there is a significantincrease in the number of trades both at ask and at bid. The average number of trades at askincreases from 69 to 92, while the median changes from 35 to 59. The p-values of the mean andmedian tests are both less than 0.01. The average number of trades at bid increases from 64 to 91,while the median changes from 34 to 61. It seems that stock splits encourage small traders notonly to buy stocks but also to sell stocks, and it is possible that the sellers reduce the trade size.The balance between the seller-initiated and buyer-initiated trades does not change after splits inthe long run.

According to the results of the trading activities, we discover the following findings. Afterstock split, the transaction frequency increases significantly, the trade size decreases significantly,while the daily trading volume in shares does not show any change. These results are largelyconsistent with the trading range hypothesis, which states that the reduced stock price tends toattract more small investors to participate in trading. The entrance of the small investors willthen cause increased trading frequency and decreased trade size. Also, since small investors aremostly uninformed, we expect to see that the number of quotes and number of trades increaseproportionally on both bid and ask sides. These are exactly what our empirical results indicate.In addition, the empirical results are also consistent with the tick size hypothesis, which statesthat the adjustment of tick size will attract liquidity traders to take part in transactions. However,neither the trading range hypothesis nor the tick size hypothesis can explain why the tradingvolume stays almost unchanged after the split. One potential explanation is that the large tradersnow use the lower price to break up their orders into even smaller chunks. Given that the market


Table 7Number of trades at ask and at bid


A. Number of trades at askMean 68.94 91.73 6.18 0.346 0.00Median 35.32 58.59 2719 0.333 0.00

B. Number of trades at bidMean 64.27 90.53 8.26 0.428 0.00Median 33.85 61.08 3252 0.430 0.00

This table presents the mean and median of the average daily number of trades at ask and at bid. The pre-split pe-riod (‘Pre’) is the [−69,−10] window relative to the announcement day (AD). The post-split period (‘Post’) is the[+10,+69] window relative to the effective day (ED). The opening, post-closing and closing contracts are excluded. Thelog-difference (percentage change) and p-value from t -tests (for mean) or sign-rank tests (for median) are reported inthe last two columns.

is fully computerized, the smaller price may make it easier for algorithmic traders to break uporders into smaller pieces. But existing theories are largely silent on these kinds of explanations.

4.4. Liquidity effects

The results of the quoted depths measured in shares are reported in Table 8. Part A describesthe results of depth at bid. The results at ask are reported in part B. The cross-sectional meansand medians of the daily average depths tell us that there is a significant decrease in the depthafter splits. The mean of the depths at bid decreases from 1599 shares before split to 1154 sharesafter split and the p-value of the log-difference is less than 0.01, which is statistically significant.This decrease in percentage is 28.7%. The median also decreases significantly, with the p-valueof the log-difference being less than 0.01. The depth at ask also shows the same tendency. Thedecrease of the depth shows that one aspect of the stock’s liquidity becomes worse after split.

The results of the spreads are represented in Table 9. The mean and median of each type ofspread are given during the two periods. The p-values of the log-difference are given in the lastcolumn to test whether the difference is significant or not. The four types of bid–ask spreads allshow a decrease after stock splits compared with those during pre-announcement periods. In PartA, the mean of the absolute effective spread decreases from 44.55 JP Yen to 23.46 JP Yen withthe p-value being less than 0.01. The decrease in percentage is 83.3%. Part B indicates that themean of the absolute quoted spread decreases from 63.73 JP Yen to 35.39 JP Yen with the p-value being less than 0.01. In percentage, the decrease is 83.2%. The mean of the relative quotedspread decreases from 1% to 0.8%, with the p-value of the log-difference being less than 0.01.The mean of the relative effective spread also decreases significantly, from 0.72% to 0.61%. Themedian test on all spread measures gives consistent results. Here our findings are different fromthose yielded by previous research, most of which find that the relative bid–ask spread increasesafter split. However, our evidence on relative spread shows that the stock’s liquidity increasesafter split.

Since the evidence from spread and depth gives inconsistent conclusions on the liquiditychange, it is necessary to adopt the quality index to combine the effects from these two di-mensions in order to detect the liquidity change after stock splits. The result in Table 10 showsthat the mean of quality index increases from 41,560 to 160,784, with the p-value being lessthan 0.01. The median also increases from 3118 to 4982 with the p-value being less than 0.01.


Table 8Quoted depth at bid and at ask


A. At bid (factor adjusted)Mean 1599.77 1154.26 −5.013 −0.287 0.00Median 857.44 574.91 −2691 −0.237 0.00

B. At ask (factor adjusted)Mean 1865.92 1139.00 −5.098 −0.323 0.00Median 947.21 648.33 −2986 −0.344 0.00

This table presents the mean and median of quotation sizes at bid and ask in number of shares. The pre-split period(‘Pre’) is the [−69,−10] window relative to the announcement day (AD). The post-split period (‘Post’) is the [+10,+69]window relative to the effective day (ED). The depth of ‘Post’ is factor adjusted which means it is divided by the splitfactor. The log-difference (percentage change) and p-value from t -tests (for mean) or sign-rank tests (for median) arereported in the last two columns.

Table 9The bid–ask spreads


A. Absolute effective spreadMean 44.55 23.46 −14.31 −0.833 0.00Median 15.30 7.35 −4646 −0.698 0.00

B. Absolute quoted spreadMean 63.73 35.39 −14.41 −0.832 0.00Median 23.78 10.96 −4637 −0.693 0.00

C. Relative quoted spreadMean 0.0100 0.0080 −5.05 −0.002 0.00Median 0.0068 0.0048 −3001 −0.001 0.00

D. Relative effective spreadMean 0.0072 0.0061 −2.63 −0.0011 0.01Median 0.0051 0.0035 −1062 −0.0008 0.00

This table presents the mean and median of the effective spread, absolute spread and relative spread. Thepre-split period (‘Pre’) is the [−69,−10] window relative to the announcement day (AD). The post-splitperiod (‘Post’) is the [+10,+69] window relative to the effective day (ED). Absolute Quoted Spread =Ask − Bid; Absolute Effective Spread = |Pt − Mt | ∗ 2; Relative Quoted Spread = (Absolute Quoted Spread)/Mt ;Relative Effective Spread = (Absolute Effective Spread)/Pt . The last four columns report the t -value (mean test), Sign-rank (median test), percentage change, and the corresponding p-value from t -tests or sign-rank tests.

From the result of quality index, we can conclude that the stock’s liquidity is enhanced on thewhole after stock splits. Thus, our findings support the trading range hypothesis and the tick sizehypothesis, which state that the stock’s liquidity increases after split.

4.5. Information asymmetry effects

We adopt the model of Glosten and Harris (1988) to estimate the adverse-selection componentof bid–ask spread. The results are presented in Table 11. The results indicate that the decreaseoccurs on the adverse selection cost but not on the order processing cost. Here, we examine the


Table 10Quality index


Quality indexMean 41,560 160,784 3.76 0.333 0.00Median 3118 4982 1893 0.342 0.00

This table presents the mean and median of the quality index. The quality index is adopted to combine the ef-fects of bid–ask spread and depth on the liquidity and it is calculated by the equation: QI = [(depth at bidt +depth at askt )]/(relative quoted spreadt ∗ split adjustment). The pre-split period (‘Pre’) is the [−69,−10] window rel-ative to the announcement day (AD). The post-split period (‘Post’) is the [+10,+69] window relative to the effectiveday (ED). The split-adjustment will be employed only on the ‘Post’. The log-difference (percentage change) and p-valuefrom t -tests (for mean) or sign-rank tests (for median) are reported in the last two columns.

Table 11Components of the bid–ask spread

Full sample (N = 138) Pre Post t-value Sign-rank Diff. p-value(Diff.)

A. Percentage adverse selection costMean 0.109 0.087 −3.59 −0.023 0.00Median 0.087 0.072 −2628 −0.017 0.00

B. Percentage order processing costMean 0.102 0.110 0.773 0.009 0.44Median 0.081 0.075 −426 −0.002 0.36

C. Adverse selection proportionMean 51.43 46.28 −2.28 −5.15 0.02Median 52.42 48.53 −1679 −3.61 0.00

This table reports the results of the adverse selection component, the order-processing component, and the proportion ofthe adverse selection component of the bid–ask spread. The pre-split period (‘Pre’) is the [−69,−10] window relative tothe announcement day (AD). The post-split period (‘Post’) is the [+10,+69] window relative to the effective day (ED).The Glosten and Harris (1988) model is adopted to estimate components: Dt = α(Qt − Qt−1) + βQtVt + μt , where α

is the order processing cost; β is the adverse selection cost. Opening and closing trades are excluded in the regression.The selected stocks also must meet the requirement of at least 20 valid trading days where the valid trading day is definedas a trading day with at least five valid transactions. The log-difference (percentage change) and p-value from t -tests (formean) or sign-rank tests (for median) are reported in the last two columns.

components in the percentage of stock price. The mean of the adverse selection cost is 0.109%during the pre-split period and 0.087% during the post-split period. The mean difference is sig-nificant, with the p-value being less than 0.01. This result is confirmed by the median test. Themedian declines from 0.087% during pre-split to 0.072% during post-split with the p-value be-ing less than 0.01. From Part B of Table 11, we can find that the order processing cost does notchange significantly after stock splits. We also give the result on the proportion of adverse se-lection component among the spread. It can be seen that this proportion falls significantly afterstock splits.

Our empirical results show that the adverse-selection component decreases after stock splits. Itmeans that information asymmetry has been reduced after stock splits. At this point, our findingssupport the trading range hypothesis, which states that information asymmetry will be reducedbecause stock splits will attract small investors, most of whom are uninformed, and thus causethe ratio of informed traders to decrease in comparison to that before split.


Is this decrease attributed to decreased participation by informed traders or increased partici-pation by uninformed traders, or the fact that both informed and uninformed traders trade morein the market while the proportion of the informed traders decreases after stock splits? This ques-tion cannot be answered before we move on to the next part, which presents the results on theuninformed and informed traders’ behavior changes. The next part also reports evidence on theprobability of informed trading before and after stock splits.

4.6. Probability of informed trading before and after stock splits

As we have discussed before, more uninformed traders will be attracted by the lower priceafter split, so the arrival rate of the uninformed traders (ε) is expected to increase. More unin-formed trader participation would, all else equal, lower the probability of informed trading (PIN).The signaling hypothesis also foresees a decrease in information asymmetry due to a speedingup of information discovery.

As Admati and Pfleiderer (1988) state, informed traders would take advantage of the unin-formed traders’ trading activity. They think the informed traders will trade more actively in theperiods when liquidity trading is concentrated. Therefore, we expect that the informed traderswill take part in trades more aggressively if more uninformed traders are attracted to the mar-ket by the lower price after stock splits. The latter situation is predicted by the trading rangehypothesis, so the arrival rate of the informed traders (μ) is expected to increase.

The estimation results of all parameters are presented in Table 12. We find that the probabilityof information event happening (α) increases significantly from the mean of 0.337 during thepre-split period to 0.419 during the post-split period, and the difference is significant at the sig-nificance level of 1%. The median test is supportive of the post-pre change and it is significantat the level of 1%. The increase in the number of information events is consistent with the re-sult that the informed traders increase significantly after stock splits. Easley et al. (2001) use theinformation events happening to test information asymmetry. Their findings of the statisticallyinsignificant increase in the probability of an information event cast doubt on the informationasymmetry explanation for splits. As stated before, we think the information events appearance

Table 12Probability of informed trading (N = 136)

Pre Post Post-Pre t-value Sign-rank p-value

α Mean 0.337 0.419 0.083 2.82 0.00Median 0.284 0.319 0.056 1499 0.00

ε Mean 41.44 63.04 25.42 4.82 0.00Median 23.01 41.33 9.69 2980 0.00

μ Mean 58.86 65.52 8.10 1.72 0.08Median 39.52 44.60 5.13 963 0.04

PIN Mean 0.230 0.208 −0.023 −2.41 0.02Median 0.204 0.197 −0.023 −1572 0.00

This table presents the cross-sectional means and medians of the probability of an information event (α), the arrival rateof uninformed traders (ε), the arrival rate of informed traders (μ), and the probability of information based trade (PIN).The pre-split period (‘Pre’) is the [−129,−10] window relative to the announcement day (AD). The post-split period(‘Post’) is the [+10,+129] window relative to the effective day (ED). Estimation on these parameters is based on theEasley et al. (1996) model. The analysis is carried out for the sample of 136 stock splits. The p-value from t -tests (formean) or sign tests (for median) are reported in the last column.


is determined only by the appearance of the informed traders. Actually, the information environ-ment should be measured by the adverse-selection component of spread that is not only causedby the probability of the informed traders’ appearance but also related to the uninformed traders’appearance. This will be discussed in more details after the PIN value is estimated in later part.

The uninformed traders’ arrival rate (ε) shows a significant increase after splits. The mean ofε increases from 41.44 to 63.04, and the change is significant at the significance level of 1%. Thesame result can be found in the median test, which is also significant at the significance levelof 1%. As to the informed traders’ arrival rate (μ), its mean increases from 58.86 to 65.52 andmedian increases from 39.52 to 44.60. The mean test and median test are both significant at thesignificance level of 10%. The increase in uninformed trades and informed trades is consistentwith the predictions of the trading range hypothesis and tick size hypothesis.

The probability of informed trading (PIN) gives the estimate for how many trades are dealtby the informed traders among the total trades. The estimated result shows that the mean of PINdecreases from 0.23 to 0.21, and this decrease is significant at the significance level of 5%. Thisresult is also confirmed by the median test. Desai et al. (1998) argue that the increase in noisetrading will reduce the adverse-selection component, while the increase in informed trading willincrease this component. The PIN value can show the combined effect when both types of tradersincrease. The trading range hypothesis and the signaling hypothesis both predict the decrease inthe information asymmetry and the fall in PIN. The empirical results in this study support thetrading range hypothesis, which predicts the increase in the uninformed traders, and the signalinghypothesis, which predicts the decrease in information asymmetry caused by the decrease in theproportion of the informed trades to the total trades.

Specifically, after split, uninformed traders are attracted by the lower price compared to thepre-split price. With more uninformed traders participating in trading the stock, the informedtraders are encouraged to trade more aggressively based on their judgment on the stock price.They will sell the stock if they think it is overpriced and buy it if they think it is undervalued. Theuninformed traders are thought to bring about the increased liquidity of the stock due to the lowerprice after split. Though both the uninformed and informed traders execute the transactions morefrequently after stock splits, the magnitude for each is different. The decrease in the PIN valueshows that the proportion of informed trades among the total trades decreases significantly. As aresult, the information asymmetry decreases, which would lower adverse selection cost and con-sequently narrow down the spread. Because the PIN value change gives a good explanation forthe previous results, including changes in the adverse selection component and bid–ask spread,the relation between the traders’ behavior and the market characteristics of the stock is justified.

5. Discussion and conclusions

In this research we comprehensively investigate the effects of stock splits on the market char-acteristics of stocks on the Tokyo Stock Exchange. By comparing the trading activity, liquidity,information asymmetry and probability of informed trading, we are able to identify whether thepredictions of existing theories are supported or not. We find that stock splits tend to increasetrading activity, enhance market liquidity, reduce information asymmetry, and lower the proba-bility of informed trading.

Our results are mildly supportive of the signaling hypothesis, which predicts that the splitsconvey good information to investors. In a semi-strong form of market efficiency, the impact ofthe release of private information (good news) from the management to investors through stocksplits will affect the originally uninformed investors and push them to purchase the stock in the


short run. Thus, the results of Table 4, which shows a significant increase in the number of tradesat ask compared to that at bid, indicating that investors are more likely to buy stocks insteadof selling them, are highly consistent with the signaling hypothesis. However, since the impactof information release will soon disappear, the signaling hypothesis remains silent on the laterresults that are based on the [10,69] trading day window.

Our findings can be viewed as highly consistent with the trading range hypothesis. Under thetrading range context, lower stock prices attract more small investors, which are largely unin-formed. If this hypothesis is true, we expect to observe an increase in both quotations and trades,as well as in market liquidity. In addition, due to the influx of noise traders, the spread tends todecrease and the adverse selection component of spread tends to shrink. In the case of probabilityof informed trading, the uninformed traders’ arriving rate (ε) is expected to increase, and the PINvalue will decrease accordingly. These are exactly what we observe from this paper.

Our empirical evidence also supports the tick size hypothesis, which predicts more liquiditytraders (or uninformed traders) participating in trading stocks after splits. The results in this studyshow that stock liquidity is enhanced after splits and that the arrival rate of uninformed tradersincreases.

As one of the most studied phenomena, the stock split is also the least understood one. Exist-ing theories try to explain the phenomenon from different aspects. Based on a comprehensiveinvestigation of the stock splits on the Tokyo Stock Exchange, our research provides soundevidence that the firms may choose to split their stocks for multi-faceted reasons such as thesignaling consideration, the trading range consideration, and the information asymmetry consid-eration because the predictions of those hypotheses are largely supported by the empirical resultsin this study.

Acknowledgments

We would like to thank Takeo Hoshi (the editor), Junbo Wang, Lifan Wu, Xianming Zhou,and two anonymous referees for their valuable comments and suggestions. Part of the job wascompleted when Guo was a PhD student in City University of Hong Kong. Various supportsfrom City University of Hong Kong (Guo, Zhou and Cai) and the “985 Project” of Sun Yat-senUniversity (Zhou) are acknowledged. All errors remain our own, of course.

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