Using newly-constructed data covering the last decade, we document that, in most of forty markets, when added to the main index, firms’ returns experience an increase in comovement with the rest of the index, reflected in higher beta and greater explanatory power of the market return. Stock turnover and analyst coverage also typically increase upon inclusion. Using various tests, we find the demand-based view of comovement (the category/habitat theories of Barberis, Shleifer and Wurgler, 2005) to provide a good explanation for many of our findings. Some results, though, suggest that information-related factors are also important in explaining the increased comovement.

We explore the link between international stock market comovement and the degree to which firms operate globally. Using stock returns and balance sheet data for companies in 20 countries, we estimate a factor model that decomposes stock returns into global, country-specific and industry-specific shocks. We find a large and highly significant link: on average, a firm raising its international sales by 10 percent raises the exposure of its stock return to global shocks by 2 percent and reduces its exposure to country-specific shocks by 1.5 percent. This link has grown stronger since the mid-1980s.

This timely volume addresses three important recent trends in the internationalization of United States equity markets: extensive market integration through foreign investment and links among stock prices around the world; increasing securitization as countries such as Japan come to rely more than ever before on markets in equities and bonds at the expense of banks; and the opening of national financial systems of newly industrializing countries to international financial flows and institutions, as governments remove capital controls and other barriers. Eight essays examine such issues as the current extent of international market integration, gains to U.S. investors through international diversification, home-country bias in investing, the role of time and location around the world in stock trading, and the behavior of country funds. Other, long-standing questions about equity markets are also addressed, including market efficiency and the accuracy of models of expected returns, with a particular focus on variances, covariances, and the price of risk according to the Capital Asset Pricing Model.

Originally published in 1996, The International Guide to Securities Market Indices provides a comprehensive overview of the securities market indices and offers assistance to professionals as well as individual investors in the selection of an appropriate securities market index, on a worldwide basis. The Guide’s identifies and catalogues available performance indicators along with their publishers and describes their relevant characteristics and a perspective on their historical price and total return performance. It also contains descriptive profiles along with historical performance data on 400 of the world’s leading global, regional and local securities market indices and sub-indices covering 10 asset classes.

In April 2000, in one day, 30 stocks were replaced in the Nikkei 225 index in Japan. We analyze the change in comovement of returns of stocks added to and deleted from the index with the returns of stocks remaining in the index. A simple model shows that upon inclusion into (deletion from) a stock index, stocks should begin to comove more (less) with the index, due to a change in their trading pattern. The empirical findings provide sound support for these predictions: In the sample, daily index betas of the added stocks rose by an average of 0.60, while the average beta of the deleted stocks fell by 0.71. Our results confirm additional predictions of the model for changes in R2, turnover, and the autocorrelation of returns upon index inclusion and deletion, and hold at daily, weekly and bi-weekly return horizons. Fundamentals based explanations fail to account for these findings. We conclude that correlated trading of index stocks causes excess comovement of stock returns. We argue that the distinct trading mechanism on the Tokyo Stock Exchange contributes to the significance and magnitude of our results.

The degree of comovement across national stock markets has increased dramatically since the mid-1990s. This has overturned a stylized fact in the international portfolio diversification literature that diversifying across countries is more effective for risk reduction than diversifying across industries. We investigate if this rise in comovement is a permanent phenomenon driven by greater economic and financial integration, or a temporary effect associated with the recent stock market bubble. At the global level, our results point to the bubble. At a regional level, we find evidence of a significant rise in market integration within Europe, possibly a reflection of institutional changes such as the EMU.

We investigate how corporate stock returns respond to geopolitical risk in the case of South Korea, which has experienced large and unpredictable geopolitical swings that originate from North Korea. To do so, a monthly index of geopolitical risk from North Korea (the GPRNK index) is constructed using automated keyword searches in South Korean media. The GPRNK index, designed to capture both upside and downside risk, corroborates that geopolitical risk sharply increases with the occurrence of nuclear tests, missile launches, or military confrontations, and decreases significantly around the times of summit meetings or multilateral talks. Using firm-level data, we find that heightened geopolitical risk reduces stock returns, and that the reductions in stock returns are greater especially for large firms, firms with a higher share of domestic investors, and for firms with a higher ratio of fixed assets to total assets. These results suggest that international portfolio diversification and investment irreversibility are important channels through which geopolitical risk affects stock returns.