Do diversified M&As improve R&D activity? Evidence from Chinese listed companies

Using the sample merger and acquisition (M&A) data of China's A-share listed companies from 2007 to 2022, this study adopts the multiphase difference-in-differences (DID) methodology to examine the heterogeneity of diversified M&A activities and their effects on enterprise innovation efficiency. Findings indicate that diversified M&As hinder the advancement of firms' innovation efficiency. Diversified M&As have a heterogeneous impact on enterprise innovation. Specifically, young enterprises, enterprises with limited cash flow, and enterprises in highly competitive industries experience a greater negative impact on innovation efficiency. Furthermore, long-term diversified operations with minimal business changes and a substantial decrease in leverage ratio harm innovation efficiency. These conclusions broaden the understanding of M&A's innovative effects and provide a practical foundation for domestic enterprises' M&A decision-making.