How to balance corporate financing and customer investment sentiment? From the perspective of external environmental shocks

Under the circumstance of external environmental shocks and the rising uncertainty, corporate financing capability and customer investment sentiment present an obvious two-way coupling relationship. The change in financing conditions will influence customers’ judgment on corporate risk and growth, while the fluctuation of investment sentiment will, through capital inflow, demand expectation, and reputation feedback, change the stability of corporate cash flow, and further affect banks’ credit granting and risk pricing. To describe this linkage mechanism, this paper constructs a tripartite evolutionary game framework among firms, customers, and banks, and, based on the strategy updating mechanism driven by payoff differences, depicts the dynamic evolution of firms’ financing and risk-mitigation choices, customers’ investment participation and sentiment adjustment behaviors, and banks’ decisions of credit support and credit contraction. On the basis of replicator dynamics, this paper introduces stochastic disturbances to characterize the impact of shock intensity, volatility, and persistence, and thus forms a tripartite stochastic evolutionary model. The research results show that: (1) Stronger firm risk-mitigation capacity and higher cooperative gains promote faster convergence toward a high-level cooperative state, whereas stronger sentiment sensitivity delays convergence and accelerates the decline of credit support; (2) As external uncertainty intensifies, the evolutionary paths shift from smooth convergence to pronounced volatility and intermittent reversals, making the contraction–pessimism feedback loop more likely to be amplified; (3) Countercyclical credit regulation that restrains excessive contraction helps sustain credit provision and stabilize expectations, thereby reducing equilibrium shifts and enhancing system resilience.