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.     

What’s in the news? The ambiguity of the information content of index reconstitutions in Germany

We analyze stock price behavior around reconstitutions of the German DAX index family from 1990 to 2013. The strong price run-up of added stocks in the 2 months preceding the announcement date remains robust until 2 months after the effective date (ED), and is fully reversed 5 months later. Conversely, stock prices of deleted firms are under pressure until 10 months after the ED. Unlike most previous studies, we find that outright entries and exits have temporary price effects, as do additions to and deletions from better-known indices; however, promotions and demotions related to lesser-known indices command permanent stock price responses. Rather surprisingly, deleted stocks consistently earn higher abnormal returns than added stocks in the 5-year post-event period. Specifically, the return differential levels out at 77.3%. We establish that this differential in permanent stock prices is attributable to differences in operating performance and media coverage. In practice, index reconstitutions do not appear to give unambiguous signals about the long-run investment appeal of affected firms. However, index fund managers not constrained by tracking error minimization would be better off holding deleted stocks for 5 years after the ED.     

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.     

Tempered stable and tempered infinitely divisible GARCH models

In this paper, we introduce a new GARCH model with an infinitely divisible distributed innovation. This model, which we refer to as the rapidly decreasing tempered stable (RDTS) GARCH model, takes into account empirical facts that have been observed for stock and index returns, such as volatility clustering, non-zero skewness, and excess kurtosis for the residual distribution. We review the classical tempered stable (CTS) GARCH model, which has similar statistical properties. By considering a proper density transformation between infinitely divisible random variables, we can find the risk-neutral price process, thereby allowing application to option-pricing. We propose algorithms to generate scenarios based on GARCH models with CTS and RDTS innovations. To investigate the performance of these GARCH models, we report parameter estimates for the Dow Jones Industrial Average index and stocks included in this index. To demonstrate the advantages of the proposed model, we calculate option prices based on the index.     

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.     

Market Reaction to Changes in the S&P SmallCap 600 Index

Firms added to (deleted from) the S&P 600 index experience a significant price increase (decrease) at announcement. Firms that newly enter (exit) the S&P universe experience a larger price increase (decrease) than firms that move between S&P indexes. Trading volumes are higher after the announcement and institutional ownership increases (decreases) following index additions (deletions). However, the price and volume effects are temporary and are fully reversed within 60 days, in contrast to the permanent effects reported for S&P 500 changes. Our results support the temporary price‐pressure hypothesis and are similar to results reported for Russell 2000 index changes.     

The liquidity effects of revisions to the S&P 500 index: an empirical analysis

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.     

Systematic liquidity risk and stock price reaction to shocks

This study examines the relationship between systematic liquidity risk and stock price reaction to large 1‐day price changes (or shocks). We base our analysis on a yearly updated constituents list of the FTSE All share index. Our overall results are consistent with the price continuation hypothesis, which suggests that positive (negative) shocks will be followed by positive (negative) abnormal returns. However, further analysis indicates that stocks with low systematic liquidity risk react efficiently to both positive and negative shocks, whereas stocks with high systematic liquidity risk underreact to both positive and negative shocks. Our results are valid irrespective of various robustness tests such as size of the shock, size of the firm, month‐of‐the‐year and day‐of‐the‐week effects. We conclude that trading on price patterns following shocks may not be profitable, as it involves taking substantial liquidity exposure.     

Inter-temporal variation in the illiquidity premium

We find evidence of a systematic link between monetary conditions and inter-temporal variation in the price of liquidity. Specifically, following an expansive monetary policy shift, funding conditions improve and market-wide liquidity increases, which is especially beneficial for illiquid securities. The improved liquidity and funding conditions reduce the returns required for holding illiquid securities. Consequently, illiquid stocks experience relatively large price increases when monetary conditions become expansive, and thus, the measured return spread between illiquid and liquid stocks expands substantially. Overall, our evidence supports the claim that the price of asset liquidity is dependent on monetary conditions.     

Liquidity Changes around Seasoned Equity Issuance: Public Offerings versus Private Placements

I investigate whether firms that issue equity, in public offerings or private placements, have improved on liquidity in the secondary market. Transaction costs, price impacts, and trading activity are examined. Results show that public offering stocks become considerably more liquid in all three dimensions. For private placement stocks, there is some evidence that trading volume increases, but effective spread and temporary price impact decline less than market‐wide changes. Furthermore, I study the behaviors of participants in the newly issued equity market. Analyses indicate that underwriters, analysts, and market makers all contribute to liquidity changes, but in different aspects.     

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.     

融资融券交易对市场和标的个股波动影响的研究

作为证券市场的重要制度之一,融资融券交易理论上应具有价格发现,价格稳定,提高流动性等基本功能。本文从融资、融券交易对市场和个股两个层面系统而全面的分析融资交易和融券交易的价格稳定作用。对市场波动性的影响的研究上主要借助GARCH族模型,VAR模型,脉冲响应和方差分解等计量分析方法;在对个股的影响上主要是借助面板数据分对个股的总体效应和个体效应展开分析。研究发现：融资交易对指数波动没有显著影响,融券交易对指数波动有一定平抑作用;融资融券交易对标的个股有价格稳定作用,除极个别个股的融资作用表现不确定。     

On Russell index reconstitution

This paper investigates whether abnormal returns permanently exist in transparent U.S. Russell index reconstitution and provides evidence to disentangle the competing hypotheses associated with the index effect in the literature. Additions to Russell 1000 generate cumulative excess returns of 10.9% from 2 days before May 31 to June 30 while stocks deleted from Russell 2000 Growth Index suffer cumulative loss of 6.6%. The effect of index reconstitution on stocks in the style switching groups is moderate while it is much smaller for stocks in the retention groups. Based on daily trading volume, there is evidence that money managers tied to Russell style indexes tend not to rebalance their portfolios actively until the time of index reconstitution to avoid tracking error. However, for stocks generating large excess returns, money managers trade them actively prior to the reconstitution. This study is supportive of the imperfect substitutes hypothesis in explaining the index effect, given the absence of complete reversal of the event period abnormal returns and of consistent improvement in liquidity for the index additions. In the joint test, the price pressure hypothesis and the liquidity hypothesis explain the marginal index effect at most by 0.12% and 3.05%, respectively, while the imperfect substitutes hypothesis explains it at least by 9.21%. Furthermore, the index effect is not purely driven by individual stock price momentum.     

The impact of naked short selling on the securities lending and equity market

This paper examines the impact of naked short selling on equity markets where it is restricted to securities on an approved list. Consistent with Miller's (1977) intuition, stocks with the highest dispersion of opinions and short sale constraints are the only stocks to exhibit significant and negative abnormal returns in the post-event period. We also find slightly higher stock return volatility and a small reduction in liquidity when naked short sales are allowed. Overall, it impairs market quality (liquidity and volatility), although there appears to be some improvement in price efficiency in stocks with high short sale constraints.     

Stock price synchronicity and liquidity

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

The Price Response to S&P 500 Index Additions and Deletions: Evidence of Asymmetry and a New Explanation

We study the price effects of changes to the S&P 500 index and document an asymmetric price response: There is a permanent increase in the price of added firms but no permanent decline for deleted firms. These results are at odds with extant explanations of the effects of index changes that imply a symmetric price response to additions and deletions. A possible explanation for asymmetric price effects arises from the changes in investor awareness. Results from our empirical tests support the thesis that changes in investor awareness contribute to the asymmetric price effects of S&P 500 index additions and deletions.     

The effect of CBOE option listing on the volatility of NYSE traded stocks: a time-varying variance approach

This paper employs the standard General Auto-regressive Conditional Heteroskedasticity (GARCH(1,1)) process to examine the impact of option listing on volatility the underlying stocks. It takes into consideration the time variation in the individual stock's variance and explicitly tests whether option listing causes any permanent volatility change. It also investigates the impact of option listing on the speed at which information is incorporated into the stock price. The study uses clean samples to avoid sample selection biases and control samples to account for the change in the volatility and/or information flows that may be caused by factors other than option listing.     

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.     

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.     

Liquidity Provision and Noise Trading: Evidence from the "Investment Dartboard" Column

How does increased noise trading affect market liquidity and trading costs? We use The Wall Street Journal's “Investment Dartboard” column, which stimulates noise trading, as a natural experiment to evaluate models of the bid-ask spread. We find that substantial increases in trading volume and significant but temporary abnormal returns occur when analysts recommend stocks in this column, especially when recommendations come from analysts with successful contest track records. We also find an increase in liquidity and a decrease in the adverse selection component of the bid-ask spread.