The National Assembly of Korea has passed the Act on the Capital Market and Investment Banking (hereinafter, the Act) on July 3rd, 2007. The Act aims at fully consolidating prior securities-related Acts, such as the Securities Exchange Act, the Futures Trading Act, the Collective Investment Scheme Act, the Trust Business Act, the Merchant Banking Act and the Money Brokerage Act. The author strongly supports the Act and expects some prospective investment bankers similar to the Goldman Sachs. The Act divides the traditional securities-related business to six sectors, such as dealing, brokerage, asset management, investment adviser, wrap and trust. If an investment banker is allowed to conduct all of these businesses, it may enjoy a lot of advantages subject to the either scale or scope economy, thereby increasing the overall welfare of financial investors. However, financial investors may encounter some disadvantages, in particular conflict of interest problems, which frequently occur between financial firms and financial investors or among financial investors themselves. Of course, the conflict of interest problems are not new ones created by the Act, because most investors have also been exposed to same problems under the current securities-related Acts. However, the Act should contain wise solutions to deal with these problems. Otherwise, the Act may face several critiques because these problems have not been seriously tested during the legislation procedures. The author feels a kind of duty to supplement the Act, thereby protecting financial consumers and strengthening the competitiveness of the financial industry in the end. The author mainly suggest one of the most important reforms in order to solve the traditional conflict of interest problems, that is the introduction of the fiduciary duty and its details to the Act. Part two analyses the current scheme of the conflict of interest regulations and develops main problems. After considering the basic concept and scopes of the fiduciary duty in general, part three applies the fiduciary duty to real conflict of interest cases in the U.S. and the E.U. Part four deals with some remarkable provisions under the Act and suggests what should be done in the near future. Part five is the conclusion part of this paper.