摘要:AbstractThis study analyses the impact of family control on decisions regarding the specialization and diversification of large business groups whose parent companies are listed on Spanish stock exchanges. Using a sample of ninety-nine companies, having identified the companies that constitute the business group, and using both binary logistic models and the Heckman two-step method to eliminate selection bias, the results show how the familial nature of the parent company favours specialization and reduces the level of the business group's diversification. In addition, we see that there are differences among family groups with respect to the concentration of their holdings in that a higher level of concentration increases the level of diversification in the family business group.