企业收购与工资：基于《工资结构基本统计调查》调查表信息的实证分析

This study examines how employee wages change after corporate acquisitions involving Japanese small and medium-sized enterprises (SMEs). We link questionnaire information from the Ministry of Health, Labour and Welfare’s Basic Survey on Wage Structure for 2015–2023 with firm and acquisition data from Tokyo Shoko Research. The sample contains about 1.09 million employee observations from roughly 28,000 firms, including about 1,100 acquired firms. Average wages increase after acquisition, and post-acquisition age–wage profiles lie above pre-acquisition profiles across all age groups. This pattern is particularly pronounced among employees who are presumed to have been employed by the firm before the acquisition. Importantly, wages are already trending upward before acquisition, while there is no evidence of post-acquisition increase in scheduled hours, overtime hours, or days worked. Econometric analyses, including a Callaway and Sant’Anna-type CSDID estimator, show similar patterns. However, because pre-acquisition trends are present, we cannot interpret the findings as descriptive evidence of causal effects.