This paper examined the motives of foreign firms' M&A activities through cases of foreign acquisitions of U.S. firms and investigated the extent to which cross-border M&As contribute to the efficient reallocation of limited economic resources. The analytical results are summarized as follows. First, restructuring measures such as employee layoffs and asset divestitures, used by foreign acquiring firms to recoup premiums paid to U.S. target firms, were attempted relatively less frequently in cross-border M&As compared to domestic U.S. M&As. Second, regardless of whether the acquisition was hostile, foreign firms divested a substantial portion of the target firm's assets after acquiring U.S. companies to other firms within similar industries that had strategic motives, and this resource allocation function is similar to that of hostile domestic U.S. M&As. Third, foreign firms continued to acquire additional companies or make additional capital expenditures after acquiring U.S. firms, suggesting that the purpose of foreign firms' M&As is to achieve synergy effects. Fourth, the level of corporate tax rates in the acquiring firm's home country was found to play an important role in attracting cross-border M&As and determining the sale price of target firms. Finally, higher acquisition premiums were realized when U.S. target firms were acquired by foreign firms in the same or related industries, or when the U.S. target firms had high R&D ratios. Taken together, all the above results suggest that acquisition premiums paid to target firms in cross-border M&As are closely related to the degree of synergy realization. Given the considerable scarcity of domestic and international empirical research literature related to cross-border M&As, the results of this study suggest new research directions in the field of cross-border M&As and can help understand the potential impact on the industrial economy of anticipated future acquisitions of domestic firms by foreign companies.