Ex-post evaluation of Edeka's acquisition of Kaiser's Tengelmann

This paper provides an ex-post evaluation of Edeka's acquisition of Kaiser's Tengelmann, one of the most prominent merger cases in German grocery retailing. The transaction is particularly relevant from a competition-policy perspective because it was initially prohibited by the German Federal Cartel Office but was later implemented following ministerial authorisation. We analyse whether the acquisition led to higher consumer prices in local markets in which Edeka had previously faced competition from Kaiser's Tengelmann. The empirical analysis is based on weekly store-product-level price data from Edeka stores in the Rhine-Ruhr region covering the period from 2013 to 2020. We apply a difference-in-differences approach that compares price developments in Edeka stores exposed to Kaiser's Tengelmann before the acquisition with comparable Edeka stores without such local exposure. The results provide no evidence of a statistically significant merger-related increase in consumer prices. This finding is robust to additional specifications accounting for local demand, supply, and competitive conditions, as well as to alternative treatment definitions and sample restrictions.