Abstract This study constructs a quasi-natural experiment based on the implementation of the Measures for the Administration of Joint Credit, and uses PSM-DID model to explore the impact of joint credit system on corporate diversification. The study shows that the joint credit system significantly restrains the corporate diversification, and the inhibitory effect is more significantly in corporates with high equity concentration or high environmental uncertainty, which supports the view of effective regulation. The mechanism test shows that enhancing the degree of bank competition, restraining the collusion between banks and corporates, and reducing the degree of corporate information asymmetry are the mechanisms through which the joint credit system works. The heterogeneity tests show that joint credit system mainly restrains corporates from carrying out unrelated diversification. The economic consequences test confirms that joint credit system enhances the value of the corporates by restraining corporate diversification.
