This paper attempts to investigate the determinants of credit rationing experienced by firms using Korean firm data. We find that large firms, bank-independent firms, and chaebol firms are more likely to be rationed out in Korean bank loan markets. Furthermore, most firms are more likely to face severe financial constraints during a monetary contraction period. These findings suggest that a tightening of monetary policy exerts a disproportionate effect on firms’ activities, with a more contraction effect on large, bank-independent, and chaebol firms.