By the end of the War, in 1945, a substantial part of the Japanese economy was controlled by many zaibatsu. When the war became serious, zaibatsu were compelled to change their character : the Mitsui and the Yasuda which had developed on the bases of banking and trade business entered such new fields as the heavy and the chemical industries, which were the main businesses of the Mitsubishi and the Sumitomo zaibatsu; the Mitsubishi and the Sumitomo had become more powerful just before the bombing by the U.S. Air Force. At the termination of the war, 35.2% of the total domestic paid-up capital was occupied by that of the companies of the ten biggest zaibatsu. The employed managers of the Mitsui and the Yasuda zaibatsu endeavored to adapt their business to the new environment in the 1930-40s, by shifting the main field of their businesses and by reforming the organizational structure of their firms. The headquarters of zaibatsu, which had been unlimited (Mitsui and Yasuda) or limited partnerships (Mitsubishi and Sumitomo), were obliged to be reorganized as joint-stock companies (corporations) in order to raise neccesary funds for new investments. By adopting the form of joint-stock company, the headquarters could offer their stocks for public subscription and could issue debentures. In the cases of the Mitsui and the Yasuda, however, zaibatsu owners were reluctant to invest in heavy industries because the center of their interest was in the preservation of their business entities. Therefore, the top-managers of the two zaibatsu made every effort to awake the owners, only to cause friction with the owners. On the other hand, the owners in the Mitsubishi usually held real power in the management. In the Sumitomo, it was an established practice that the owners delegate authority over management to the top-managers. On account of this practice, no severe conflict was ever seen between the owners and the managers in the two zaibatsu. After the war, main zaibatsu were dissolved according to the order of the GHQ; the headquarters of zaibatsu was broken up; the owners and managers of zaibatsu were purged; and the stocks of zaibatsu-affiliated companies were offered to the general public, and these companies became firms independent of each other. After the Peace Treaty came into effect in 1952, however, the former zaibatsu subsidiaries began to regather together and to reorganize their own financial groups respectively. These financial groups are called “Kigyo-shudan” instead of “zaibatsu.” Among Kigyo-shudan, the Mitsubishi and the Sumitomo groups grew up most remarkably. On the other hand, the solidarity of the Mitsui and the Yasuda groups was weak because of the top-managers' reluctance to renew zaibatsu. Moreover, the top-managers opposed the former owners' comeback and involvement in the former subsidiaries. It may be argued from the above that the prewar pattern of owner-manager relations that developed in respective zaibatsu had a great influence upon the solidarity and potentiality of each Kigyo-shudan in the postwar period.