We use industry valuation differentials across European countries to study the impact of membership in the European Union as well as the Eurozone on both economic and financial integration. In integrated markets, discount rates and expected growth opportunities should be similar within one industry, irrespective of the country, implying narrowing valuation differentials as countries become more integrated. Our analysis of the 1990–2007 period shows that membership in the EU significantly lowered discount rate and expected earnings growth differentials across countries. In contrast, the adoption of the Euro was not associated with increased integration. Our results do not change when the sample is extended to include the recent crisis period.

We propose a new, valuation-based measure of world equity market segmentation. While we observe decreased levels of segmentation in many countries, the level of segmentation remains significant in emerging markets. We characterize the factors that account for variation in market segmentation both through time as well as across countries. Both a country's regulation with respect to foreign capital flows and certain nonregulatory factors are important. In particular, we identify a country's political risk profile and its stock market development as two additional local segmentation factors as well as the U.S. corporate credit spread as a global segmentation factor.

We propose an exogenous measure of a country's growth opportunities by interacting the country's local industry mix with global price to earnings ( PE ) ratios. We find that these exogenous growth opportunities predict future changes in real GDP and investment in a large panel of countries. This relation is strongest in countries that have liberalized their capital accounts, equity markets, and banking systems. We also find that financial development, external finance dependence, and investor protection measures are much less important in aligning growth opportunities with growth than is capital market openness. Finally, we formulate new tests of market integration and segmentation by linking local and global PE ratios to relative economic growth.