We have been concerned with investigating the structure of rate-of-return comovements among major international equity markets. Working with 12 such markets we have analyzed the structural features of the configurations over alternative time periods (one-, three-, five- and ten-year periods) and the intertemporal stability of the configurations.
On the issue of intertemporal stability we found considerable one-year and three-year stability, but somewhat weaker stability in the five-year case. As a measure of stability we used cophenetic correlation coefficients between successive (in time) dendrograms. This technique was described in the methodology section.
We uncovered several interesting structural features. There seems to be a core of international markets that have higher degrees of similarity than the other markets. Furthermore, these markets (the United States, Canada, the Netherlands, Switzerland, West Germany and to a lesser extent, Belgium) may be generally described as relatively well developed and open to international capital flows. There is also an obviously strong tie between the United States and Canadian markets. There are less strong, but identifiable ties between France and Belgium, Germany and the Netherlands, and England and Australia. Many of these results parallel Ripley's  findings. We also noticed some countries that tend to be least similar to most other countries: Austria and Italy. Ten-year results corroborated these findings.
This study is only descriptive. We have only attempted to identify international equity market structure and structural change. A logical subsequent research area is to explain observed structural properties and the causes of structural change. We hope that our research will help provide some basis for this further analysis.