Background Firms need financial support in their development process. External financing is one of the main ways in which firms can obtain funding (Guariglia, 2008). However, most firms find it difficult to meet financing needs through formal credit channels due to problems such as high project risks and insufficient collateral (Hutchinson and Gul, 2004; Koellinger, 2008). Therefore, firms tend to engage in informal financial activities to obtain finance, such as shadow banking activities, which