In terms of scales and numbers, investment trust funds are much bigger and more than corporate trust funds in Korea. After analyzing the legal status of collective investment entities at the investment trust fund industries in detail, this paper considers the legal issues surrounding combinations of funds, in particular combinations of investment trust funds. This paper deals with two large issues. First, part Ⅱ does briefly consider the legal status of collective investment entities at investment trust funds. Even though same persons are not able to serve as both sponsors and trustees at investment trust funds under the current Act, relevant provisions indicate that collective investment entities as sponsors may in fact act like trustees. That is, they are sometimes subject to trustee-like duty and liability, and thus are substantially sponsors and trustees. Two theories, including legal trust-relation theory and substantive trust-relation theory, are relevant to identify and explain the rights and duties among collective investment entities and other parties. One important issue whether sole decision by a collective investment entities without the consent of beneficiaries are possible or not will be dealt with in depth. Second, part Ⅲ introduces the necessity of fund reorganizations and the complicate procedures between investment trust funds. Third, part IV analyzes the appropriateness of a legal term "merger" between investment trust funds and the necessity of introducing the acquisition of funds modeled on the U.S. law. Part V shows conclusion remarks of this paper.