Pharmaceutical Mergers and Acquisitions in Crisis and Non-Crisis Periods: Effects on Shareholder Value Creation Evidence from the United States and Europe

Abstract

This thesis examines whether pharmaceutical acquisitions announced during macroe conomic crisis periods are associated with different abnormal returns than acquisi tions announced during non-crisis periods, and whether these effects differ between U.S. and European acquirers. Using a sample of 135 completed pharmaceutical-to pharmaceutical acquisitions announced between 2005 and 2025, the study applies a dual-horizon event study framework based on cumulative abnormal returns (CAR) and buy-and-hold abnormal returns (BHAR). The findings show that crisis-period acquisitions are associated with more favor able short-term abnormal returns for U.S. acquirers, particularly in the CAR(−3,+3) window. In contrast, the corresponding effects for European acquirers are consistently weaker than those observed for U.S. acquirers and are not statistically distinguishable from zero in net-effect tests. The long-term BHAR results provide no consistent evidence of persistent abnormal performance and remain sensitive to methodological specification. The analysis further shows no statistically significant differences across crisis types. Overall, the findings suggest that favorable market reactions to pharmaceutical acquisitions during crisis periods are short-term, institutionally dependent, and concentrated in specific transaction settings rather than reflecting broad or persistent shareholder value creation.