We estimate the effects of hospital mergers, using detailed data containing medical supply transactions (representing 23% of operating costs) from a sample of US hospitals, 2009–2015. Pre‐merger price variation across hospitals (Gini coefficient 7%) suggests significant opportunities for cost decreases. However, we observe limited evidence of actual savings. In this retrospective study, targets realized 1.9% savings; acquirers realized no significant savings. Examining treatment effect heterogeneity to shed light on theories of “buyer power,” we find that savings, when they occur, tend to be local, and potential benefits of savings may be offset by managerial costs of merging.

中文翻译：

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合并和边际成本：有关医院购买者权力的新证据

我们使用包含2009-2015年美国医院样本中医疗供应交易的详细数据（占运营成本的23％）来估计医院合并的影响。合并前医院间的价格差异（基尼系数7％）表明降低成本的重大机会。但是，我们观察到的实际节省的证据有限。在这项回顾性研究中，目标实现了1.9％的节省；收购方未实现重大节省。通过研究处理效果的异质性以阐明“买方权力”的理论，我们发现储蓄发生时，储蓄往往是局部性的，储蓄的潜在利益可能会被合并的管理成本所抵消。