In this study we study the conflict of interests (COI) among customers of financial investment services companies (or securities firms) that operate diverse businesses in Korea as well as between the firms and their customers. Financial firms, in general, engage in diverse business activities with different customers, and each of business process has potential for COI between counter parties. For example, when a financial firm engages in a transaction with a customer, it gains valuable information about the client. Then, the possibility of COI arises because the firm has incentives to exploit the information to reap any kind of profit, perhaps to win additional deals for itself or a third party at that person's expense. The root cause of a COI is the fact that a financial firm usually acts as an agent, and capitalizes from information asymmetry, often inherent in the firm's transactions with individual customers. In this sense, financial investment services companies in Korea are appropriate subjects for this study for their diverse business areas for a wide array of customers, in which COI is very likely to emerge during their operations. In fact, some studies have been conducted on the COI in universal banking transactions at Korean financial investments services companies (securities firms). Those studies include Park and Shin (2007), Park, Choi, and Lee (2011). However, in general those institutions that provide universal banking services (e.g. securities firms in Korea) establish chinese walls to prevent the COI with another businesses. This creates difficulty in accessing data for COI cases. Another challenge is that many studies in this topic have produced conflicting results. In Lin and McNichls (1998), Kim and Choi (2008) and other related studies, they argue that affiliated analysts have the potential of COI. Cowen, Groysberg, and Healy (2006) and Park and Youn (2009), in contrast, insist that a possibility of that COI is lower due to maintaining their own reputation. As such, to increase objectivity of our study we select the most fundamental businesses of a financial investment services company: research analysis and underwriting. Then, we try to identify the COI in these core businesses. Specifically, we conduct an empirical analysis to verify the existence of COI in the Korean financial investment services companies, in this paper securities firms, focusing on measuring any possibility for biases that get involved in research analysis. The results of the study are as follows. First, it confirmed that analysts in Korean financial investment services companies (securities firms) working for an IPO underwriter tend to release less positive earnings outlooks and they had high accuracy in forecast. But our study results also indicate a possibility that COI in the industry could have stemmed from informational asymmetry among some analysts, resulting in their reporting not as accurately as it could otherwise be. These analysts, as opposed to third party analysts, tend to publish earnings forecasts that include smaller forecast errors and are less positive, while, nonetheless, are less accurate on the whole. Second, the same is also true among the most trusted financial analysts with solid reputations for being regarded as thorough and reliable in their reporting. The empirical analysis is made based on the assumption that an analyst's opinion is influenced primarily by the characteristics of the financial investment services company where the analyst is working. In Korea financial investment services companies exert significant influence on their research function, and this seems to cause a COI. In other words, analysts reported more frequently if their securities firms had more brokerage business market share. That evidence was more clear when their securities firms had industrial affiliates. And in the middle-sized securities firm, their analysts reported more frequently if their securities firm had more investment banking business market share. Third, we found that the affiliated analysts could raise the COI by selecting more positive long-term IPO firms when their securities firm were affiliated with bank and asset management firms. Despite the recent move toward strengthening regulation in the financial sector, the frequent outbreaks of COI cases, within both domestic and foreign financial firms, reinforces the need for a stronger legal and institutional foundation to more effectively address the problem. Hopefully, the outcomes of this study will contribute to further improvement of financial investment services companies in their standards of work ethics in Korea, which will then raise the competitiveness of Korea's financial industry as a whole. As domestic capital market grows and concentration and diversification of securities firms accelerate, accordingly, we conclude that strengthening the firewall among businesses of securities firms is imperative for the improvement of their competency and the prevention of investors' losses due to the COI.