The research first summarizes the theoretical mechanism of digital finance to improve financial efficiency and sustainability; then, it proposes three hypotheses. After that, a DEA-BCC model and a super-efficiency DEA model are constructed to estimate a series of financial efficiency levels in 31 Chinese provinces. Utilizing the estimated financial efficiency values, this paper further tests each of the three hypotheses using both a random effects model controlling for cross-sectional correlation problems and an LSDV model, respectively. The findings show that (i) technological advance is the main driver of financial efficiency improvement in each region in China, while the role of scale effect in improving financial efficiency is weakening; (ii) the development of digital finance does significantly contribute to the improvement of regional financial efficiency; and (iii) the increase in both the breadth of coverage and depth of adoption of digital finance are core driving forces for the promotion of financial efficiency, with the breadth of digital financial coverage a stronger positive effect. Hence, this study can provide an important reference for policymakers and financial institutions to better understand the relationship amongst digital finance, financial efficiency, and sustainability as well as achieve sustainable financial inclusion.

The research aims to investigate the existence of peer effect in mergers and acquisitions and study its impact on corporate sustainable development. It first constructs a peer effect testing model to examine whether there is peer effect in mergers and acquisitions, based on quarterly data in China between 2005 and 2019. Then, two econometric models are proposed separately to explore the impact of economic policy uncertainty on the merger and acquisition peer effect, as well as how the peer effect affects corporate sustainability. The key findings show that (i) firms tend to imitate their peers’ merger and acquisition behaviors, which means that the peer effect does exist in mergers and acquisitions; (ii) economic policy uncertainty could strengthen the peer effect in mergers and acquisitions; (iii) the peer effect has a negative impact on corporate sustainable development, and the impact is more significant within a relatively short period. Therefore, this study enriches the research of behavior science in mergers and acquisitions, improves the accuracy of peer effect testing and enables both firms and policymakers to mitigate irrational imitation in merger and acquisition deals, thus achieving their sustainable development goals.

Sustainable growth relies on common prosperity, which is reflected in increasing total income and equitable income distribution. This study first proposes the theoretical mechanisms by which digital financial development affects residents’ total income and income distribution. After that, a two-stage generalized method of moments estimation model with endogeneity treatment is constructed to investigate the impact of digital finance on residents’ total income in 31 Chinese provinces. Moreover, Moran’s I and a spatial autoregression model are used to explore the impact of digital finance on residents’ income distribution. The results demonstrate that digital financial development can significantly contribute to the increase in residents’ total income in both urban and rural areas, thus contributing to regional sustainable wealth growth. In addition, digital finance has a spatial direct effect and a spatial spillover effect on the optimization of residents’ income distribution. This indicates that a region’s digital financial development benefits regional sustainable wealth growth, as it not only can improve residents’ income distribution within the same region but also can promote the income distribution of neighboring regions.