Green credit is an important market for China’s green financial development. In reality, the market players involved in green credit are the government, financial institutions and SMEs. The main body of direct transactions of funds is comprised by financial institutions and enterprises, both of which want to maximize their profits, but there are often conflicts between economic benefits and environmental protection. In order to cater to green indicators and maximize their own interests, enterprises may carry out false environmental protection behaviors, obtain recognition and preference of the investment market through greenwashing, and engage in non-green production activities with high risk and high return [
55]. Due to information asymmetry, for financial institutions, bearing the risk is too high to recover the loss of all the loan amount. The blockchain itself has the characteristics of openness, decentralization, and traceability, and it can be well applied to the financing scenario. Compared with the traditional mode, the financial mode of access to blockchain technology can reduce the cost of credit investigation and the risk of loss while bearing certain service costs. Increasing the default cost of the defaulting party may be a good solution to the problem of greenwashing [
20]. Government subsidies can guide the upgrading of green industries, promote the development of green finance, better help green SMEs with positive externalities, solve the imbalance of economic and social development, and obtain economic benefits and social welfare [
56]. At the same time, the input of government subsidies is a burden for national finance, and it is necessary to balance and manage fiscal revenue and expenditure. How to achieve this balance is a problem that the government needs to think about. On the basis of Xu [
54], this paper combines the blockchain and greenwashing issues with China’s green credit policy and expands the government’s choice of behavior. The government, as a regulator, quantifies and measures the benefits of environmental protection, supervision and subsidy costs, and it also serves as one of the main players in the tripartite game. This paper focuses on a macro dynamic financing market.
3.2. Model Parameters
As shown in
Table 1, this paper sets the environmental benefits and social welfare brought about by the green production of SMEs in the green credit market as
W2. The government will provide financing subsidies
H for SMEs with limited funds to engage in green production risks. In addition to the cost of capital, the government needs to invest a certain amount of administrative resources in the design of relevant policies. It is necessary to bear the cost of supervision and law enforcement while establishing monitoring and evaluation mechanisms. The existence of incentives also reduces tax revenue. The total cost is recorded as
C2. The government has a regulatory function, especially for the trend of funds paid by the government. The regulatory intensity of providing subsidies and not providing subsidies is different, and the cost of different regulatory intensity is also different. When the government pays the funds, we set its supervision as
α. If the subsidy policy is not adopted, there is no need to follow up the flow of subsidy funds and the supervision
β is weaker (
α >
β) [
51]. Enterprises also have greenwashing production. The emergence of this situation has allowed green funds to flow to non-green areas and failed to achieve the expected environmental effects. Moreover, this fund can be used for the normal production of other green SMEs, and the government will vigorously punish this behavior, recorded as
P. As an emerging technology, blockchain can improve the level of information construction, enhance the effectiveness of public services, promote digital economic growth and industrial innovation, and set the relevant income as
W1. As a platform builder, the government’s construction cost is
C1.
Financial institutions are mainly based on deposit and loan interest spreads, and the deposit interest rate is set as i1. The preferential loan interest rate under the green credit policy is i2 (i2 > i1). That is, the financing cost of green production of SMEs. Its green credit line is L. The business cost of financing for SMEs, such as credit audit, formalities, etc., is set as C3. After adopting the blockchain financial model, the service cost of accessing the blockchain technology platform is C4. If the SMEs providing financing bleach green production, then the financial institutions may bear a variety of damage, such as if the enterprise cannot repay the loan on time, the financial institutions are exposed to the risk of debt default, resulting in the funds not being recovered. Financial institutions may face bad debt, the loss of the value of the assets and bear the loss of reputation and the possibility of legal compliance risk. Under the principle of green finance, financial institutions and highly polluting enterprises may be subject to social and public condemnation, affecting their reputation and business development, and in serious cases, they will be responsible for the legal liability, recorded as S.
The green production yield of small and medium-sized enterprises is r
1, while greenwashing production has high risk and high return, and the yield is r
2 (r
2 > r
1). If green production is adopted, a certain cost is required, including updating or modifying existing equipment to meet the needs of environmental protection and energy efficiency. In the procurement of raw materials and supplier cooperation, it is necessary to consider that raw materials must meet environmental protection standards and assess the sustainability of the supply chain. The costs of certification and compliance review, as well as training and governance costs, are recorded as C
5. If you access blockchain technology, SMEs in accordance with the rules of the agreement on green production must agree to the timely repayment of loans. Then, according to the formula algorithm and smart contract of blockchain decentralization, digital currency or other forms of trustworthy rewards can be provided for participants’ honest performance, G [
31]. In this way, participants are encouraged to actively follow the rules and enhance the operation effect of the system. Through the consensus mechanism in the blockchain, participants participate in the verification transaction according to the rules, and the destruction of greenwashing production will face punishment, M. It is also the compensation obtained by financial institutions through the reward and punishment mechanism of the blockchain service platform. In addition, there is a credit evaluation mechanism in the blockchain, and honest and trustworthy participants receive higher credit scores and reputations. The occurrence of malicious behavior will lead to a series of consequences, such as corporate trust, corporate reputation and image damage [
32]. We record these losses as invisible value losses, V, under greenwashing behavior.
The revenue matrix of the three parties is shown in
Table 2, which can be derived from the above hypothesis.
3.3. Replicator Dynamics Equation and Stability analysis of Evolutionary Game
According to the above model assumptions and variable settings, the government’s expectation of adopting a green credit subsidy strategy is
Ex. The expectation of not adopting green credit subsidies is
E1−x. Therefore, the government’s evolutionary game replication dynamic equation is:
Similarly, the expectations for financial institutions to adopt the blockchain financial strategy and maintain the traditional financial strategy are as follows: E
y, E
1−y. Thus, the evolutionary game replication dynamic equation of financial institutions is:
The expectations for SMEs to adopt the green production strategy and greenwashing production strategy are as follows:
Ez,
E1−z.
When let then .
When then is an evolution-stable point. The government will not choose a subsidy.
When , then is an evolution-stable point. The government will choose a subsidy.
When let then and .
When , any value of y is an evolution-stable state.
When and , then is an evolution-stable point. When the probability of SMEs choosing green production is less than z0, financial institutions will adopt the blockchain financial model.
When , and , then is an evolution-stable point. When the probability of SMEs choosing green production is more than z0, financial institutions will adopt the traditional financial model.
Based on the above analysis, the conclusions are expressed in a three-dimensional coordinate system, which leads to the dynamic evolutionary trend of financial institutions’ behavior, as shown in
Figure 1.
When let , then , and .
When , any value of z is an evolution-stable state.
When and , then is an evolution-stable point. When the probability of the government choosing green credit subsidy is less than x0, SMEs will adopt the way of greenwashing production.
When , and , then is an evolution-stable point. When the probability of the government choosing green credit subsidy is more than x0, SMEs will adopt the way of green production.
Based on the above analysis, the conclusions are expressed in a three-dimensional coordinate system, which leads to the dynamic evolutionary trend of financial institutions’ behavior, as shown in
Figure 2.
By analyzing the local stability of the matrix of the corresponding replication dynamic system, the evolutionary stability strategy of the evolutionary game is obtained. According to the replication dynamic equation of the three parties, we can obtain the Jacobian matrix of the system.
When all the eigenvalues of the matrix are negative, the equilibrium point is the evolutionary stable point (
ESS); when the sign of all the eigenvalues of the matrix is determined and there are positive eigenvalues, the equilibrium point is unstable. However, if the equilibrium of an asymmetric game is asymptotically stable, it must be consistent with the strict Nash equilibrium and be a pure strategic equilibrium. Therefore, in order to discuss the asymptotic stability of the equilibrium point of the replicator dynamics equation, only the equilibrium point of the replicator dynamics equation needs to be discussed with a pure strategy. This paper only considers the pure strategy and does not consider the mixed strategy, so only the positive and negative eigenvalues of the first eight stable points are analyzed in
Table 3 and
Table 4.
In practice, the initial parameters should satisfy . The reason for this is that the use of the blockchain platform reduces the investment cost of financial institutions in financing SMEs, that is, the service cost of the blockchain platform is less than the financing cost of green small and medium-sized enterprises. E1(0,0,0), E2(1,0,0), E4(0,0,1), E6(1,0,1). The eigenvalues do not meet the symbolic requirements of the Lyapunov discriminant method for evolutionary stable points. Whether the eigenvalues E3(0,1,0), E5(1,1,0), E7(0,1,1), E8(1,1,1) satisfied the Lyapunov criterion needs further discussion. As , . The stability of these four equilibrium points is discussed as follows:
Case I: In the green credit financing system, the total benefit of the loss compensation for financial institutions and the incentive for enterprises to be trustworthy brought by the use of blockchain finance is less than that of the greenwashing production enterprises under the weak regulatory punishment and the loss of invisible value (). For the government, the difference between the benefits of strong regulation and the benefits of weak regulation is less than the cost of government subsidies (). The eigenvalues of the equilibrium point (0,1,0) are all negative. So, {non-subsidy, blockchain, greenwashing} is a stable strategy.
Case II: In the green credit financing system, the total benefit of the loss compensation for financial institutions and the incentive for enterprises to be trustworthy brought about by the use of blockchain finance is less than that of the greenwashing production enterprises under the strict regulatory punishment and the loss of invisible value (). For the government, the difference between the benefits of strong supervision and the benefits of weak supervision is greater than the cost of government subsidies, and the benefits of strong supervision under the government subsidy model are higher (). The eigenvalues of the equilibrium point (1,1,0) are all negative. So, {subsidy, blockchain, greenwashing} is a stable strategy.
Case III: In the green credit financing system, the total income from the loss compensation of financial institutions and the incentive for enterprises to keep their promises brought by blockchain finance is greater than the income from the use of greenwashing production enterprises to bear weak regulatory penalties and invisible value losses (). For the government, the difference between the benefits of strong regulation and the benefits of weak regulation is less than the cost of government subsidies (). The eigenvalues of the equilibrium point (0,1,1) are all negative. So, {non-subsidy, blockchain, green} is a stable strategy.
Case IV: In the green credit financing system, the total income from the loss compensation of financial institutions and the incentive for enterprises to keep their promises brought by blockchain finance is greater than the income from the use of greenwashing production enterprises to bear weak regulatory penalties and invisible value losses (). For the government, the difference between the benefits of strong regulation and the benefits of weak regulation is greater than the cost of government subsidies (). The eigenvalues of the equilibrium point (1,1,1) are all negative. So, {subsidy, blockchain, green} is a stable strategy.