Stock Price and Volume Effects Associated with Compositional Changes in European Stock Indices

This paper provides further evidence of price and volume effects associated with index compositional changes by analysing the inclusions (exclusions) from the French CAC40 and SBF120 indices, as well as the FTSE100. I find evidence supporting the price pressure hypothesis associated with index fund rebalancing, but weak or no evidence for the imperfect substitution, liquidity and information hypotheses. The results improve on recent evidence from the S&P500 index. The evidence for the FTSE100 additions shows, in particular, that markets learn about an imminent inclusion and incorporate this information into prices, even before the announcement date.     

Does Inclusion in a Smaller S&P Index Create Value?

This study finds overall increases in equity value surrounding addition to the S&P SmallCap and MidCap indexes from 1996 to 2003 and investigates sources of the value gains. Following addition, there are significant increases in proxy variables for stock liquidity and investor recognition, and changes in these variables are impounded into the permanent component of announcement share price revisions. We also find that changes in capital investment intensity are increasing in changes in stock liquidity, consistent with a reduction in the cost of capital following index addition.     

The competitive effects of S&P 500 Index revisions

Firms added to the S&P 500 Index gain a competitive advantage over their non‐S&P 500 industry competitors. They experience positive stock valuation effects at the expense of competitors. The inclusion is associated with both reductions in financial constraints and the cost of equity and increases in capital investment for the newly added firms. When the increase in capital investment is greater, they gain more market share and enjoy better valuation effects. Rivals’ share price responses are negatively related to the announcement effect of the newly added firm. Deletions from the index, however, do not have symmetric effects.     

Do Demand Curves for Small Stocks Slope Down?

Stocks added to the S&P 500 generally experience positive abnormal returns following the announcement. Several competing explanations exist for this reaction, but small sample sizes and other issues make it difficult to distinguish among them. We examine this subject using the small‐cap Russell 2000 index, which has several advantages over the S&P 500 in this context. Our primary finding is that stocks added to or deleted from the Russell 2000 experience significant changes in stock price and trading volume, but the effect is transitory. The results support the price pressure hypothesis.     

The Impact of Changes in the FTSE 100 Index

This paper investigates FTSE 100 index membership changes, which are determined quarterly by market capitalization and should have no information content. Return reversal around index additions and deletions suggests that buying (selling) pressure moves prices temporarily away from equilibrium, consistent with short‐term downward sloping demand curves. In contrast to widely reported results for the S&P 500, there is no evidence of permanent price effects. Further results suggest that investor awareness and monitoring due to index membership do not explain the price effects. There is statistically significant anticipatory trading in stocks that just fail to be promoted to the FTSE 100.     

The liquidity effects associated with addition of a stock to the S&P 500 index: evidence from bid/ask spreads

This study examines changes in stock liquidity, as measured by the bid/ask spread, when a stock is added to the S&P 500 Index. The paper presents evidence of a significant decrease in the bid/ask spread upon S&P 500 addition, however, this effect is limited to only those stocks that were not trading listed options. Further, the decrease in the bid/ask spread for nonoptioned stocks is accompanied by a significant and permanent increase in share price and trading volume. While optioned stocks experience a permanent increase in trading volume, they experience only a temporary increase in share price. The findings for optioned stocks support the hypothesis that the price and volume effects associated with S&P 500 addition derive from temporary price pressure. Findings pertaining to the nonoptioned stocks indicate that the price and volume effects associated with S&P addition reflect enhanced stock liquidity. The decrease in the bid/ask spread for nonoptioned stocks is attributed to informational efficiencies achieved via index arbitrage trading, and it is argued that this effect is mitigated for optioned stocks due to the pre-existence of arbitrage trading between the option and the underlying stock.     

The S&P500 index effect reconsidered: Evidence from overnight and intraday stock price performance and volume

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.     

A re-examination of the index effect: Gambling on additions to and deletions from the S&P 500's ‘gold seal’

This study examines the abnormal returns, trading activity, volatility and long-term performance of stocks that were added to the S&P 500 index. By using a three-factor pricing model that allows for firm size and value characteristics as well as market risk, we are able to shed new light on the widely observed ‘index effect’. We find that the CAPM tends to overstate the performance of large firms and to understate the performance of small firms. We also find a transitory increase in trading volume between the announcement and a few days after the effective date. In terms of the firm's operating performance, we find a significant increase in earnings per share after inclusion, which combines with the stock price rise to leave the average price-earnings ratio largely unaltered. Examining a unique sample of deletions of international companies and replacements with US companies, we find that deleted stocks experienced a considerable and permanent fall in price, inconsistent with the Investor Recognition Hypothesis. The “seal” of S&P 500 index membership has very long-term effects and inclusion appears not to be an information-free event.     

S&P 500 Membership and Managers’ Supply of Conservative Financial Reports

Our study is motivated by economic theory and the debate among practitioners, standard setters, and academics on the role of conditional conservatism in financial reporting. We find that managers provide less conditionally conservative financial reports after their firms are added to the Standard and Poor's (S&P) 500 index. S&P 500 membership is expected to reduce information asymmetry between managers and outside stakeholders due to an increased flow of public and private information. As a result, the contracting benefits of conservative accounting choices are reduced, and managers are less willing to provide conditionally conservative reports. In contrast, we find that managers provide more conditionally conservative financial reports after their firms are deleted from the index. Firms being deleted from the S&P 500 index probably incur an increase in information asymmetry. Overall, our results provide evidence consistent with conditional conservatism being a response by managers to the information needs of financial statements users.     

S&P 500 index addition,liquidity management and Tobin's Q

This study examines the revision in cash holdings and the market valuation of investment opportunities of 475 firms added to the Standard & Poor's 500 (S&P 500) stock market index from 1980 to 2010. We find that newly indexed firms have evolved to significantly lower cash balances, which we partially explain by the decreasing growth opportunities following index inclusion. Consistent with index inclusion loosening financial constraints, we document a larger decrease in cash for index inclusions in sectors with high financial dependence. We sort S&P 500 inclusions by corporate governance quality but do not find any empirical support that changes in cash and Tobin's Q are related to management entrenchment.     

The index premium and its hidden cost for index funds

This paper empirically investigates the index premium and its implications from 1990 to 2005. For additions to the S&P 500 and Russell 2000, we find that the price impact from announcement to effective day has averaged + 8.8% and + 4.7%, respectively, and −15.1% and −4.6% for deletions. The premia have been growing over time, peaking in 2000, and declining since then. The implied price elasticity of demand increases with firm size and decreases with idiosyncratic risk, supporting theoretical predictions. We also introduce a new concept that we label the index turnover cost, which represents a hidden cost borne by index funds (and the indexes themselves) due to the index premium. We illustrate this cost and estimate its lower bound as 21-28 bp annually for the S&P 500 and 38-77 bp annually for the Russell 2000.     

Strategic trading by index funds and liquidity provision around S&P 500 index additions

We examine the trades of index funds and other institutions around S&P 500 index additions. We find index funds begin rebalancing their portfolios with the announcement of composition changes and do not fully establish their positions until weeks after the effective date. Trading away from the effective date is more prevalent for stocks with lower levels of liquidity and among large index funds, which is consistent with index funds accepting higher tracking error in order to reduce the price impact of their trades. Small and mid-cap funds provide liquidity to index funds around additions, and added stocks with a greater proportion of these natural liquidity providers experience lower inclusion returns.     

Asymmetric stock price and liquidity responses to changes in the FTSE SmallCap index

We examine market reactions to changes in the FTSE SmallCap index membership, which are determined quarterly based on market capitalization and are free of information effects. Our main results are asymmetric price and liquidity responses between the firms that are shifted between FTSE indexes and the firms that are new to FTSE indexes. Firms promoted from a smaller-cap to a larger-cap FTSE index experience a permanent increase in stock price accompanied by improvements in liquidity. Similarly, firms demoted from a larger-cap to a smaller-cap FTSE index experience a permanent decrease in stock price accompanied by declines in liquidity. In contrast, firms added to the FTSE SmallCap index that were not previously in FTSE indexes show a transitory price gain and declines in liquidity. The results support the liquidity and price pressure hypotheses.     

An Anatomy of the “S&P Game”: The Effects of Changing the Rules

This study analyzes the effects of changes in S&P 500 index composition from January 1986 through June 1994, a period during which Standard and Poor's began its practice of preannouncing changes five days beforehand. The new announcement practice has given rise to the “S&P game” and has altered the way stock prices react. We find that prices increase abnormally from the close on the announcement day to the close on the effective day. The overall increase is greater than under the old announcement policy although part of the increase reverses after the stock is included in the index.     

What Drives the S&P 500 Inclusion Effect? An Analytical Survey

We present an analytical survey of the explanations—price pressure, downward-sloping demand curves, improved liquidity, improved operating performance, and increased investor awareness—for the increase in stock value associated with inclusion in the S&P 500 Index. We find that increased investor awareness is the primary factor behind the cross-section of abnormal announcement returns. We also find some evidence of temporary price pressure around the inclusion date. We find no evidence that long-run downward-sloping demand curves for stocks, anticipated improvements in operating performance, or increased liquidity are related to the cross-section of announcement or inclusion returns.     

A comprehensive long-term analysis of S&P 500 index additions and deletions

We investigate the long-term effects of S&P 500 index additions and deletions on a sample of stocks from 1962 to 2003 and find a significant long-term price increase for both added and deleted stocks, with deleted stocks outperforming added stocks. The long-term price increase for added stocks can be attributed to increases in institutional ownership, liquidity, and analyst coverage, and a decrease in the shadow cost in the long-term. However, while deletion has no significant effect on analyst coverage and shadow cost, we find a rebound in the institutional ownership and liquidity of deleted stocks. The difference in the long-term price increase of added and deleted stocks can be explained by analyst coverage and operating performance.     

Pinning in the S&P 500 futures

We show that Standard & Poor's (S&P) 500 futures are pulled toward the at-the-money strike price on days when serial options on the S&P 500 futures expire (pinning) and are pushed away from the cost-of-carry adjusted at-the-money strike price right before the expiration of options on the S&P 500 index (anti-cross-pinning). These effects are driven by the interplay of market makers' rebalancing of delta hedges due to the time decay of those hedges as well as in response to reselling (and early exercise) of in-the-money options by individual investors. The associated shift in notional futures value is at least $115 million per expiration day.     

The impacts of index rebalancing and their implications: Some new evidence from Japan

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.     

Stock reaction to dividend savings of convertible preferred calls: Free cash flow or price pressure effects?

Calls of in-the-money convertible preferred stock typically induce dividend savings for the firm, since preferred dividends exceed common stock dividends. Prior research finds that these savings are negatively related to stock returns at call announcement and argues that the market expects managers to abuse the increased free cash flow. This paper finds that dividend savings are closely related to call size, suggesting other explanations. Larger calls experience a more negative announcement reaction. Consistent with temporary liquidity effects, there is a price reversal during the conversion period, which is greater for larger calls.     

Overreaction of country ETFs to US market returns: Intraday vs. daily horizons and the role of synchronized trading

In this paper we study the intraday price formation process of country Exchange Traded Funds (ETFs). We identify specific parts of the US trading day during which Net Asset Values (NAVs), currency rates, premiums and discounts, and the S&P 500 index have special effects on ETF prices, and characterize a special intraday and overnight updating structure between these variables and country ETF prices. Our findings suggest a structural difference between synchronized and non-synchronized trading hours. While during synchronized trading hours ETF prices are mostly driven by their NAV returns, during non-synchronized trading hours the S&P 500 index has a dominant effect. This effect also exceeds the one that the S&P 500 index has on the underlying foreign indices and suggests an overreaction to US market returns when foreign markets are closed.