Customers are the important resources of enterprises, which reflect the development potential and operational capacity of enterprises. However, when an enterprise relies too much on some major customer resources, it will lead to an increase in customer concentration, and the operating risks of the enterprise will also increase significantly. Therefore, optimizing customer resources is not only paid attention by regulatory authorities, but also the focus of theoretical and practical attention. However, the problem of enterprises relying on major customer resources is still prominent. As digital transformation breaks industrial boundaries, enhances the innovation ability of enterprises, and reshapes the original competitive pattern and value creation mode of enterprises, it may impel the reconfiguration of enterprise customer resources.

Accordingly, the study finds that the implementation of digital transformation by enterprises can help to reduce the concentration of enterprise customer resources, which avoids over-reliance on major customer resources. The conclusions are still valid after using a series of robustness and endogeneity tests. The impact mechanism test reveals that digital transformation will form the innovation-driven effect and cost reduction effect, and then promote the reconfiguration of enterprise customer resources. Further research shows that the role of digital transformation is heterogeneous. The impact of digital transformation on adjusting excessive concentration of customer resources is more significant for enterprises with lower total factor productivity, younger enterprises, enterprises with higher location financial inclusion index, and non-state enterprises. The extension study finds that the adjustment of digital transformation is also restricted by the nature of major customers. When major customers are affiliated enterprises or listed enterprises, the role of digital transformation will be weakened. In addition, compared with other technologies, the application of digital technology like artificial intelligence and cloud computing can more effectively reduce the concentration of enterprise customer resources and avoid over-dependence on major customer resources. This paper expands the theoretical research of the relationship between digital transformation and market micro-subject structure, and provides empirical evidence for predicting the trend of enterprise customer restructuring and policy formulation during the digital transformation period.