This paper tests the hypotheses on the relationships between the size of financial market and the financial structure, which were developed in an earlier paper by the same author, "A Theory on the Scope of Financial Activity," the Korea Development Review, Spring 1991. This test utilizes panel data as well as time-series data during 1970s and1980s of 11 OECD countries (USA, Japan, U.K.,. Germany, France, Canada, Italy, Netherlands, Belgium, Sweden, and Spain) and Korea. The size of financial market is defined as the size of real and nominal total financial assets in the economy, and the financial structure is defined as the importance (ratio) of direct financing through securities or (to) indirect financing through intermediaries given the size of financial market. The test results support the following relationships. 1. The size of financial market significantly affects the structure of financial industry, while the directions (signs) of the outcome differs on individual countries. 2. The financial structure tends to converge to a certain stable equilibrium without a tendency of one financing method dominating the other as the size of financial market grows: The results based on the panel data suggest that the importance (ratio) of direct or (to) indirect financing tends to converge to the sample mean as the size of financial market expands. These results seem to suggest that a competitive equilibrium in the deregulated financial industry will consist of both specialized and multi-product financial firms, resulting in mixed form of specialized and universal banking systems. 3. As world financial markets fully integrate and all the countries consequently face this single, common world market, the financial structures of individual countries will become increasingly similar. 4. During the interim pace towards the mixed equilibrium with specialized as well as universal financial intermediaries, a more universal system will dominate the deregulated financial industry in countries with relatively small financial markets. At the same time, a more specialized banking system will dominate in countries with relatively large financial markets: The logit analysis based on panel data with the dummy dependent variable of 1 and 0 for universal and specialized banking system, respectively and the explanatory variable of the size of the financial market suggest a strong and significant negative relationship. 5. The choice of banking system strongly influences the process of convergence to the final equilibrium: The results based on the panel data imply that the universal banking system tends to expedite the process of the convergence of the financial structure to the sample mean and vice versa for the specialized banking system.