Abstract: By innovatively introducing the mixed shock of fintech, fintech-corporate default risk and fintech-policy uncertainty into the ABNK (Agent-Based New Keynesian) model, this study for the first time quantitatively analyzes the moderating effect of fintech on the relationship between economic policy uncertainty and commercial bank performance within the ABNK framework. The research findings are as follows: Firstly, both single policy uncertainty shock and single default risk shock will reduce bank profits and equity returns, leading to a decline in bank performance; while both single enterprise fintech shock and single bank fintech shock will increase bank profits and equity returns, resulting in an improvement in bank performance. Secondly, the improvement of enterprise fintech is more helpful than the development of bank fintech in alleviating the inhibitory effect of economic policy uncertainty on the performance of commercial banks. Thirdly, the improvement of enterprise fintech can respectively moderate the negative impact of enterprise default risk shock on bank profits and bank equity returns at the 68% level, and simultaneously promote the increase of bank loan returns at the 8% level; correspondingly, developing bank fintech can mitigate the negative impact of economic policy uncertainty on bank profits and equity returns at a level of approximately 44%, while increasing bank loan yields at a level of 30%. Therefore, the government should ensure policy stability and predictability, and commercial banks need to enhance their ability to resist policy uncertainty and accelerate digital transformation to improve risk control efficiency.

Key words: financial technology, economic policy uncertainty, bank performance, ABNK model