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S&P 500 Affiliation and Stock Price Informativeness
Abstract
When firms are added to a stock index, more information should be discovered, traded on, and incorporated into their stock prices, making them more informative. We test this hypothesis using a large sample of additions to the S&P 500 index. Using two alternative statistical tests, we find that the stocks added experience more random, less predictable return and, thus, appear to be priced more efficiently information-wise. We further find concurrent increases in institutional ownership and investor awareness, which tend to contribute to the higher pricing efficiency, adding to the literature. These findings should be of interest to academics and practitioners.
... Unlike many benchmark indices (Russel 2000, Nikkei, or Topix), the S&P 500 Index does not follow a calendar reconstitution approach. Changes to the index are made on an as-needed basis (Liu, 2019), while the level of transparency associated with the restructuring decision is relatively low (Afego, 2017). ...
... As such, the restructuring event should not bear any new information. (Liu, 2019). ...
We examine how abnormal returns and abnormal return determinants change when a company is added to S&P 500. Newly added companies experience a significant increase in abnormal returns around the announcement and addition dates. This increase is accompanied by an improvement in liquidity and a decrease in associated shadow cost. While before their addition, firm-specific abnormal returns can be explained by price impact, they are explained by changes in trading activity during the addition event. Additionally, companies with higher leverage ratios benefit more from index affiliation.
... The economic sectors referred to in this paper are based on the Global Industry Classification Standard (GICS) developed by the S&P 500. The inclusion and deletion rules from the index are well captured in Liu (2020). The U.S. Research Returns Data from the CRSP database are used in conjunction with the Siblis Research data for further analysis. ...
In this paper, a novel stock-to-sector-to-benchmark ratio or anomaly that assists investors in automating stock selection, diversification, and optimization for portfolio management is introduced. The approach uses three market capitalization values, one for the individual stock, one for the sector, and one for the benchmark capitalization, to calculate the ratio. The results of this paper prove the efficacy of the proposed methodology. Out of the eleven constructed for the period under study, all the portfolios constructed beat the benchmark in terms of the highest weighted returns, lowest risk, and highest Sharpe ratio during the sample period (1979 to 2019). Fama‒French three-factor and five-factor models are used to assess whether the factor loadings influence performance. Although the Fama-French three-factor models showed a statistically significant alpha, the asset pricing model had an average adjusted R² of 13%, while the adjusted R² of the Fama-French five-factor model had an average of 60% (excluding a single stock-based portfolio). These portfolios exhibit a statistically significant negative SMB, which implies that the performance of the portfolios is affected by large capitalization stocks, which is in direct contrast to the popular belief that outperformance is influenced mainly by small-cap stocks.
Purpose
We examine the changes in a firm’s cost of debt after it is included in or removed from the S&P 500. The extant literature on index composition focuses on the cost of equity and lacks an understanding of the impacts on a firm’s cost of debt capital upon inclusion in or removal from a major stock market index. Therefore, we address the following question: Does a firm’s cost of debt change around its inclusion in or removal from the S&P 500?
Design/methodology/approach
We develop two hypotheses based on the research question and use univariate and multivariate fixed-effects analyses to test them. Furthermore, to ensure robustness and address endogeneity concerns, we employ a matched control sample difference-in-difference statistical framework.
Findings
Inclusion in the S&P 500 lowers a firm’s cost of debt by 0.145% and 0.200%, on average, in the six- and three-month periods after inclusion. Furthermore, after a firm is removed from the index, a firm’s cost of debt increases on average 0.380% and 0.260% in the six- and three-month periods in the post-inclusion period when compared to the pre-inclusion period.
Originality/value
This study contributes novel insights into the cost of debt and index composition literature. It provides insights for academics, investors, creditors, corporate managers and index selection committees.
Purpose
The purpose of this study is to compare market reactions to the change in the demand by index funds between large and small company stocks by examining the transition of the S&P 500, S&P 400 MidCap and S&P 600 SmallCap indexes from market capitalization to free-float weighting. This unique information-free event allows not only avoiding confounding information signaling and investor awareness effects but also comparing the effect of the decrease in demand on stocks of different sizes.
Design/methodology/approach
This study uses the event study methodology to calculate abnormal returns and trading volume around the full-float adjustment day. It also tests for significant changes in institutional ownership and liquidity. Multivariate regressions are used to examine the relation of liquidity changes and price elasticity of demand to the cumulative abnormal returns around the full-float adjustment day.
Findings
This study finds significant decreases in stock price accompanied with significant increases in trading volume on the full-float adjustment day, and significant gains in quasi-indexer institutional ownership and liquidity. The main finding is that cumulative abnormal returns around the event period are related to changes in the number of quasi-indexer and transient institutional shareholders, not to changes in liquidity or price elasticity of demand.
Originality/value
This study provides the first comprehensive comparison analysis of stock market reactions to the decline in demand between large and small company stocks. As an important implication for future studies of the index effect, changes in institutional ownership should be considered in the analysis.
The historical promotion of the real estate industry in the Global Industry Classification Standard (GICS) system to a new headline sector should raise the informational efficiency of pricing for the asset class. We test this hypothesis for the first time using a large sample of publicly traded real estate investment trusts (REITs). Using two alternative statistical tests, we find that REIT returns become more random and less predictable following the event, suggesting better informational efficiency of REIT pricing. Furthermore, we find that the higher pricing efficiency is related to higher institutional ownership in the asset class in the same period. These findings should be of interest to academics and practitioners.
The literature is rich with examples of price clustering in financial markets. This study focuses on the relation between mutual fund ownership (both active and passive) and stock price clustering. To the extent that mutual funds are sophisticated investors, we posit that their trades are associated with lower levels of price clustering. We find support for this hypothesis as total, active, and passive mutual fund ownership are negatively related to the degree of price clustering. Surprisingly, price clustering’s association to passive (e.g. index) mutual fund ownership is an order of magnitude greater than to active ownership.
The practice of periodically reconstituting equity indices suggests that changes to the composition of an index can impact the performance of firms whose stocks are added to or dropped from the index. This paper reviews and provides a comprehensive assessment of the academic literature on how changes in the composition of a stock index impacts prices, trading volume and other firm attributes. The review focuses on post-2000 contributions. It highlights and critically discusses major areas of controversy, disagreement and debate in both the empirical and methodological literature, and puts forth a promising agenda for future research. This is the first comprehensive survey of studies on the index effect and it should be particularly useful to portfolio managers and investors.
This paper investigates the relationship between aggregate stock market trading volume and the serial correlation of daily
stock returns. For both stock indexes and individual large stocks, the first-order daily return autocorrelation tends to decline
with volume. The paper explains this phenomenon using a model in which risk-averse “market makers” accommodate buying or selling
pressure from “liquidity” or “noninformational” traders. Changing expected stock returns reward market makers for playing
this role. The model implies that a stock price decline on a high-volume day is more likely than a stock price decline on
a low-volume day to be associated with an increase in the expected stock return.
In this article we test the random walk hypothesis for weekly stock market returns by comparing variance estimators derived
from data sampled at different frequencies. The random walk model is strongly rejected for the entire sample period (1962–1985)
and for all subperiods for a variety of aggregate returns indexes and size-sorted portfolios. Although the rejections are
due largely to the behavior of small stocks, they cannot be attributed completely to the effects of infrequent trading or
time-varying volatilities. Moreover, the rejection of the random walk for weekly returns does not support a mean-reverting
model of asset prices.
We find that the firms included in the S&P 500 index are characterized by large increases in earnings, appreciation in market value, and positive price momentum in the period preceding their index inclusion. This strong preinclusion performance predicts 1) the permanent increase of market value and 2) the change in return comovement, reflected in declines of size, value, and momentum betas, following index inclusion. Nonevent firms with similar performance experience similar appreciation in value and changes in comovement coincident with the event firms. Contrary to the consensus in the literature, our results indicate that—after accounting for the firms’ extraordinary preinclusion performance—index inclusion has no permanent effect on value and comovement.
This paper investigates financial attention using novel panel data on daily investor online account logins. We find support for selective attention to portfolio information. Account logins fall by 9.5% after market declines. Investors also pay less attention when the VIX volatility index is high. The level of attention and the attention/return correlation are strongly related to investor demographics (gender, age) and financial position (wealth, holdings). Using a new statistical decomposition, we show how aggregate and individual household trading are related to investor attention.
Since September, 1976, stocks newly included into the Standard and Poor's 500 Index have earned a significant positive abnormal return at the announcement of the inclusion. This return does not disappear for at least ten days after the inclusion. The returns are positively related to measures of buying by index funds, consistent with the hypothesis that demand curves for stocks slope down. The returns are not related to S & P's bond ratings, which is inconsistent with a plausible version of the hypothesis that inclusion is a certification of the quality of the stock.
This study examines the impact of FTSE 100 index revisions on the informational efficiency of the underlying stocks. Our study spans the 1986–2009 period. We estimate the speed of price adjustment and price inefficiency from the partial adjustment with noise model of Amihud and Mendelson (1987). We report a significant improvement (no change) in the informational efficiency of the stocks added to (deleted from) the FTSE 100 index. The asymmetric effect of additions and deletions on informational efficiency can be attributed, at least partly, to certain aspects of liquidity and other fundamental characteristics, which improve following additions but do not diminish after deletions. Cross-sectional analysis also indicates that stocks with low pre-addition market quality benefit more from joining the index.
We find that the firms included in the S&P 500 index are characterized by large increases in earnings, appreciation in market value and positive price momentum in the period preceding their index inclusion. This strong pre-inclusion performance predicts (1) the permanent increase of market value and (2) the change in return comovement, reflected in declines of size, value and momentum betas, following index inclusion. Non-event firms with similar performance experience similar appreciation in value and changes in comovement coincident with the event firms. Contrary to the consensus in the literature, our results indicate that – after accounting for the firms’ extraordinary pre-inclusion performance – index inclusion has no permanent effect on value and comovement.
This study focuses on S&P500 inclusions and deletions, examining the impact of potential overnight price adjustment after the announcement of an S&P500 index change. We find evidence of a significant overnight price change that diminishes the returns available to speculators although there are still profits available from the first day after announcement until a few days after the actual event. More importantly, observing the tick-by-tick stock price performance and volume effects on the key days during the event window for the first time, we find evidence of consistent trading patterns during trading hours. A separate analysis of NASDAQ and NYSE listed stocks allows for a detailed examination of the price and volume effect at an intra-day level. We find that index funds appear to cluster their rebalancing activities near to and after the close on the event date, suggesting that they are more concerned with tracking error than profit.
When stocks are added to (deleted from) an index, more (less) information should be generated and incorporated into their prices, leading to higher (lower) pricing efficiency and lower (higher) return predictability for them. We test this hypothesis for the first time using membership changes in the Nikkei 225. Employing two alternative tests, we document that the return series become more (less) random and, thus, less (more) predictable for stocks added (deleted). We further find that these changes are related to changes in the information environment for the stocks involved, supporting the hypothesis. These findings should be of interest to portfolio managers.
We study liquidity effects following S&P 500 index revisions. Using a recent sample of S&P 500 additions, we find a sustained increase in the liquidity of the added stocks. Further, the improvement in the liquidity of added stocks is due primarily to a decrease in the direct cost of transacting and a smaller decline in the asymmetric information component. Finally, the event period cumulative abnormal returns for additions are significantly associated with the decrease in the effective spread, particularly the decline in the direct cost of transacting. In contrast, the liquidity of deleted stocks declines over the three months following deletion.
This paper investigates the impact of the listing of options on the Nikkei Stock Average (NSA) on the volatility, bid-ask spread and trading volume for stocks listed in the First Section of the Tokyo Stock Exchange. Our results indicate that trading volume, volatility, and bid-ask spreads decline for the stocks contained in the Nikkei 225 Index after the listing of the index options. Cross-sectional regressions that control for changes in spread, volume, and price indicate that the options listing is associated with decreases in volatility for the index stocks. We conjecture that the observed results are consistent with the hypothesis that the advent of options trading causes a migration of speculative and market-wide information-oriented trading activity from the underlying market to the options market.
This study examines the variance of returns on common stocks around the time exchange-traded options are listed on these stocks. The evidence indicates that stock return variance declines after options listing, and that this phenomenon is not fully explained by contemporaneous shifts in market volatility. In addition, stock market trading volume increases, on average, after options are listed on firms' stocks. I examine the hypothesis that the variance changes are related to changes in ‘trading noise” in the stock, but find little direct support for this explanation.
This study investigates the Nikkei 225 rebalancing. Unlike those for changes in the S&P 500, the price effects are permanent for both additions and deletions despite significant price reversals around both the announcement and effective days. The permanent price effects are shown to be consistent with the imperfect substitute hypothesis. Furthermore, the ‘arbitrage game’, as documented for the S&P additions, is played with both the Nikkei 225 additions and deletions. Lastly, consistent with its higher popularity, the Nikkei 225 changes induce more pronounced price and volume effects, more arbitrage trading, but less long-term volume effects than the Nikkei 500 reshuffles.
Bibliography: leaves 53-56. Robert C. Merton.
This paper analyzes the relation of stock volatility with real and nominal macroeconomic volatility, economic activity, financial leverage, and stock trading activity using monthly data from 1857 to 1987. An important fact, previously noted by Robert R. Officer (1973), is that stock return variability was unusually high during the 1929-39 Great Depression. While aggregate leverage is significantly correlated with volatility, it explains a relatively small part of the movements in stock volatility. The amplitude of the fluctuations in aggregate stock volatility is difficult to explain using simple models of stock valuation, especially during the Great Depression. Copyright 1989 by American Finance Association.
Some researchers have recently suggested that lower transaction costs induce small (or noise) traders to trade more actively, thus increasing both the noise component and total volatility of asset prices. We empirically evaluate this conjecture by examining changes in volatility surrounding the abolition in 1975 of fixed brokerage fees on the NYSE. We use a control sample of NASDAQ issues that are unaffected by the abolition. Using a variety of tests, we find that the lowering of transaction costs is associated with a significant reduction in volatility for the aggregate NYSE portfolio and five size-ranked portfolios, even after accommodating market-wide conditional heteroskedasticity. In addition, prices are better characterized as random walks following the fixed fee abolition, a result that is due to a lower noise component in returns and more rapid price adjustment. We conclude that an increase in transaction costs could lead to higher volatility and less-informative prices.
SEQUELS ARE RARELY AS good as the originals, so I approach this review of the market efficiency literature with trepidation. The task is thornier than it was 20 years ago, when work on efficiency was rather new. The literature is now so large that a full review is impossible, and is not attempted here. Instead, I discuss the work that I find most interesting, and I offer my views on what we have learned from the research on market efficiency.
Attempts to identify price pressures caused by large transactions may be inconclusive if the transactions convey new information to the market. This problem is addressed in an examination of prices and volume surrounding changes in the composition of the S&P 500. Since these changes cause some investors to adjust their holdings of the affected securities and since it is unlikely that the changes convey information about the future prospects of these securities, they provide an excellent opportunity to study price pressures. The results are consistent with the price‐pressure hypothesis: immediately after an addition is announced, prices increase by more than 3 percent. This increase is nearly fully reversed after 2 weeks.
An Anatomy of the ‘S&P Game’: The Effects of Changing the Rules
- M Beneish
- R Whaley
The Price Response to S&P 500 Index Additions and Deletions: Evidence of Asymmetry and a New Explanation
- H Chen
- G Noronha
- V Singal
All That Glitters: The Effect of Attention and News on the Buying Behavior of Individual and Institutional Investors
- B Barber
- T Odean
Institutional Investors and the Informational Efficiency of Prices
- E Boehmer
- E Kelley