MIT Sloan Management Review

Why Mergers Fail and How to Spot Trouble Early

M&A activity remains a high‑stakes gamble, with nearly half of large U.S. acquisitions eventually undone. A 27‑year study of 1,636 S&P 500 deals shows a 46% divestiture rate and an average ten‑year lag before breakup. Failures cluster around two patterns: poor pre‑deal fit—often cultural or strategic misalignment—and unforeseen post‑deal disruptions that erode value. The authors propose the Corporate Divorce Matrix, a diagnostic that maps fit and environmental risk to help executives anticipate and avoid costly separations.