Until recently the dominant theoretical perspective applied in corporate governance research has been the agency theory. Agency theory offered the first satisfactory explanation to the governance of modern corporations since Berle and Means(1932) pointed out the essential problems inherent in the separation of ownership and control. However. it is undeniable that the exclusive reliance on agency theory has constrained the advances incorporate governance studies. Therefore. an alternative approach to corporate governance is necessary to recognize the various mechanisms and structures that may operate across the different forms of corporations. Recent studies brought up the issues of corporate governance to the forefront of organization theory. If we take the perspective of organization theory. corporate governance can be broadly conceptualized as a problem of managing various interdependences(Fligstein & Freeland. 1995). Diversified business groups are sets of legally separate firms bound together in formal or informal ways. They are under tight control of founders as entrepreneurs and their family members (Granovetter. 2005 : Guillen. 2001). The national economies of most countries. except for Anglo-American economies. have been dominated by various forms of business groups for decades or even centuries. Hence. understanding business groups is still a very important issue in modern capitalist economies. Most business groups are closely associated with family members of the founder who exert controlling power directly or indirectly through diverse means. Among these multiple means. the equity structure among the group-affiliated companies is the most powerful mechanism to maintain the dominant control of families in most business groups. Drawing on theoretical insights from institutional theory, we view the family control of big business groups as an institutional factor that exist s in the Korea economic system. Also the family's equity investment can be recognized as a family's strategic response to the institutional pressures from both foreign and domestic markets. The family ownership and cross-share holding among group-affiliated companies are both direct and prevalent mechanisms that enable the owner family members to keep on controlling the entire business group. In Korea, these family member s have institutionalized their dominant status in the entire business group. To understand the family's control as an institutional mechanism, we should consider the underlying logics that differentiate the interests of family from those of other stakeholders. In order to clarify the family's control mechanism, we focus more closely on both the economic and non-economic interest s th at influence the incentives of the family member's equity stake in each affiliate company. In this paper, we investigate the factors th at affect the family ownership using a sample of group -affiliated firms in Korea during the period of 2001-2006. The Korean Fair Trade Commission(KFTC) legally defines a business group and identifies a set of firms as a big business group which is often called as chaebol. Since group-affiliated companies ar e of our major interests, we restricted our sample to firms which have been designated as big business groups by the government for six consecutive years. Under this criterion, 11 business groups are selected, and the final sample consists of 1061 firm-year observations. Drawing on institut ion theory, we propose six hypotheses and test them empirically. Specifically, dimensions of (1) profit seeking, (2) group control. and (3) social legitimacy are considered as major factors that influence the level of the founding family's equity investment. We argue that the family's ownership stake can be determined by not only economic interests but also noneconomic factor s such as an investment in symbolic assets of the affiliated- firm's history and the pursuit of social legitimacy. The random effect tobit regression results show that the families did not pursue their economic interests based on the expectation of superior individual firm performance. Instead, they made investment decisions in terms of group control and social legitimacy. In particular, families mobilize the relational resources originated both from equity structures of group-affiliated companies and intra-group transactions. Families have more equity stakes in group- affiliated companies higher up in the hierarchy of the equity structure. The high level of equity-holding status measured by the centrality index gives controlling power over the whole group to the family. Families also invest more in group-affiliated companies that have longer history. Firm hist ory can enhance group identity among family members and historical legitimacy of family control. In ad dit ion. we found that the impairment of social legitimacy by NGOs. especially. shareholder activists groups can influence the level of families' equity investments. Shareholder activist groups can hurt reputations of business groups by raising issues related to corporate governance problems. Families reduce the level of their direct equity ownership when their members or affiliated companies are involved in a legal suit from NGOs. Implications of our study are as follows. First. although recent studies of neo-institutional theory take into account power and interest s in their explanations, researchers need to consider more diverse interests as a crucial factor that sets on the institutionalization as a process. In this research, institutional and interest-based explanations for the family's ownership structure can enrich our understanding of various issues related to the Korean business groups and complement the efficiency-based perspectives of corporate governance research. Second. our findings highlight the importance of further investigation of various institutional logics which operate differently following the divergent paths of each business system. The Anglo-Saxon view of an ideal organization is largely grounded in the neo-classical economic tradition. In the neoclassical economic paradigm. firms are conceived as isolated units and keeping them apart is a crucial condition for advanced capitalism. However, business groups display distinctive organizational patterns of ownership. management, and production. We need to understand that the emergence of particular organizational forms can be best understood in the context of a country-specific system of inter-relations among suppliers. consumers. regulators and many intermediaries operating in the country. Even though component firms are legally separate. business groups are more than just the sum of individual companies. Internally they are socially structured, and each of them plays a different role within a group. In business groups. families are very well aware of the role structure of equity ties among member firms and actively utilize these relational resources to maintain their control over the entire business group. In this study. we suggest that a more balanced theoretical approach is needed to fully understand different organizational forms and the ways these institutions operate. An Anglo-Saxon view can not be a general theory of capitalism. and it should be cautiously applied to non-western economies where institutional assumptions are different.