Many securities firms are running asset management businesses as well as underwriting businesses. However, when securities firms run these two businesses at the same time, a conflict of interest may arise between customers of underwriting business and those of asset management business. For example, securities firms want to favor customers of asset management businesses at the expense of those of the underwriting businesses because they can get more profit from the former business which is growing much faster than the latter one. We test for conflict of interest by comparing the underwritten prices of IPOs from 1999 through 2006 in Korea by securities firms both with and without asset management businesses. We find that IPOs are more deeply underpriced when they are underwritten by securities firms running asset management businesses. This shows that there may be conflicts of interest among them which favor customers of the asset management business by channeling deeply underpriced IPO stocks into their running funds. In addition, conflicts of interest turn out to be more conspicuous among securities firms having larger fund market shares or those that have begun with the asset management business first before running the underwriting business. Our results imply that the combination of underwriting and asset management businesses may cause conflicts of interest and the degree of conflicts of interest may vary in accordance with how deeply they are engaged in the asset management business.