This paper examines that financial distress of Chaebol-affiliated firm spills over to other affiliates within the same Chaebols using credit rating change data. We find that credit rating downgrade announcement of Chaebol-affiliated firm negatively affects all other affiliates on average because: (1) Chaebol-affiliated firms share their internal capital markets and (2) they are controlled by several family members who hold the majority of the business group. We also suggest that ownership and board structure in the business group determines the extent of the spillover effect. We find that family directors in Chaebol-affiliated firm affect spillover effect in business group. In sum, the results indicate that both ownership structure and board structure are key factors to understand within family business group.