In this study, we investigate the relationship between the ownership of controlling shareholders and the proportion of bank loans in total debt. According to the literature, when the ownership of controlling shareholders is large enough, it incentivizes the controlling shareholders to pursue their private interests. If it is low, however, outside investors and other stakeholders, including the governance system of the company, prompt the managers of the company to maximize the firm value (Demsetz, 1983; Fama and Jensen, 1983; Morck et al., 1988). Thus, there is anon-linear relationship between the ownership of controlling shareholders and the firm value that is, until a certain level of executive ownership is reached, it increases the firm value, but if it exceeds a critical level, the firm value decreases due to controlling shareholders' pursuing their private interests (Stulz, 1988; Morck et al., 1988; McConnell and Servaes, 1990; Kim, 1992). According to the theories that controlling shareholders behave differently based on their ownership, in this study, we test whether there is a non-linear relationship between the ownership of controlling shareholders and different debt capital choices. We empirically confirm that the ownership of controlling shareholders has a non-linear relationshipwith the proportion of bank loans in total debt. Specifically, the controlling shareholders whose ownership is below (above) a certain level prefer (accept fewer) bank loans. We also consider the firm characteristics and the level of monitoring when investigating the relationship between the ownership of controlling shareholders and debt capital choices. Our analysis shows that a firm in financial distress seems to avoid the use of bank loans even when the ownership of controlling shareholders is low. We argue that the controlling shareholders of a firm in financial trouble are more likely to follow their private interests and evade the tight monitoring of the banks providing the loans (Johnson et al., 2000; Lin et al., 2013). Our investigation also addresses how a company's age affects the relationship between the ownership of controlling shareholders and debt capital choices. If a firm is older and the ownership of controlling shareholders is high (low), a bank loan (public debt) is preferred. To analyze the effect that monitoring has on debt capital choices, we use several important proxies for monitoring, such as the ownership of foreign investors, institutional ownership, and the presence of multiple large shareholders. The test shows that foreign investors seem to effectively monitor firms, such that when foreign ownership is large enough, the improved monitoring encourages firms to take more bank loans (Baek et al., 2004; Shin et al., 2004). When there are multiple large shareholders, the ownership of controlling shareholders is positively related to the proportion of bank loans in total debt, even over the critical level of controlling shareholder ownership. We interpret this result as follows. Multiple large shareholders can monitor a firm and its controlling shareholders (Maury and Pajuste, 2005), which prompts the firm to use more bank loans despite the fairly large ownership of controlling shareholders. Finally, we implement additional analyses for robustness checks. We investigate the endogeneity between a firm's ownership structure and its debt capital choices using a causal analysis. The investigation verifies our hypothesis that although the ownership of controlling shareholders affects debt capital choices, the latter does not affect the former. In addition, our results hold with different methods of inference, such as clustered error estimation or Fama and MacBeth's (1973) method. Therefore, we confirm our hypothesis that a firm with less ownership of controlling shareholders takes more bank loans than one with more ownership. This study contributes to the literature in the following ways. First, we apply Panano and Roell's (1998) theory on the decision between IPO and block sales of equity to debt capital choices. They argue that controlling shareholders consider the benefits and costs of IPO compared to the injection of new equity capital through other large shareholders. The cost of IPO is the listing cost and the benefit is less monitoring by diverse minority shareholders after the IPO. We apply this theory to debt capital choices and empirically verify it. Second, we expand on Lin et al. (2013) by including the ownership of controlling shareholders as a main variable in our investigation. Lin et al. use a wedge in their study and find a linear relationship between it and debt capital choices, whereas we find a non-linear relationship between the ownership of controlling shareholders and debt capital choices. Third, we consider the level of monitoring in our main investigation. Extant studies include a firm's characteristics, but not the level of monitoring, in this vein of research. Fourth, the Korean financial market is one of the best testing platforms from which to observe controlling shareholders' behavior, especially the pursuit of private interests, as most companies have concentrated ownership structures and are included in conglomerates known as “Chaebols.”