Consolidate? Diversify? Post‐M&A supply base structural changes and operational performance

Abstract Firms increasingly engage in mergers and acquisitions (M&As) to improve their network positions and enhance performance. Yet, how the fundamental structure of the merged supply base changes after the M&A and how the structural changes affect the performance are largely unknown. Building upon the strategy‐structure‐performance framework, this study investigates dual roles of supply base structural changes in M&A events, namely, as an outcome and as a moderator to post‐M&A performance. In particular, we examine how the size and the country diversity of the merged supply base change after M&As, as well as how these structural changes affect the merged firm's operational performance. We conduct a difference‐in‐differences analysis by comparing firms that engaged in M&A events (treatment group) with those comparable firms that did not engage in any M&A events (control group). The results show that the merged firms tend to reduce the size of their supply bases after M&As. In addition, our results demonstrate that both supply base consolidation (i.e., reducing the number of suppliers) and country diversification (i.e., spreading suppliers across multiple countries) improve the merged firms’ post‐M&A operational performance, an effect that becomes stronger for horizontal M&As. We also explore how the type of M&As (i.e., horizontal vs. nonhorizontal), industry relatedness between the two merging firms, and the purposes of M&As affect the post‐M&A structural changes to the supply bases. This study helps inform supply managers the important roles of supply base in M&As to enhance post‐M&A operational performance or to limit the synergies when not properly done.