About

The paper

Price Effects in U.S. Merger Retrospectives: A Meta-Analytic Approach. Andrew Olsen (Princeton), Reed Orchinik (MIT Sloan), and Marc Remer (Swarthmore). 2026. Working Paper.

Read the current draft (SSRN).

How to cite this site. If you use this website in your research, we ask that you also cite the Working Paper above, which describes the findings on this site in greater detail.

Methods in brief

  • Unit of analysis: estimated merger price effects from individual retrospectives.
  • Scope: U.S. horizontal mergers; reduced-form price effects.
  • Two samples. The Meta-Study Sample (42 papers, 273 estimates) restricts to log-price difference-in-differences specifications for comparability. The larger sample (68 papers, 444 estimates) is broader and includes other regression specifications.
  • Models. A Bayesian hierarchical random-effects meta-analysis on the Meta-Study Sample, with random effects nested at the regression, merger, and industry levels. A companion Bayesian hierarchical beta-regression on the larger sample synthesizes the direction of effects across studies with different outcome variables, a methodological extension developed in the paper.
  • Robustness. Sensitivity to priors, nesting structure, and sub-samples; \(p\)-curve and funnel-plot tests for publication bias; industry-specific meta-analyses for airline and hospital mergers.

Full details, priors, and diagnostics are in the paper. Code and data: link coming soon.

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