A rollup is a series of acquisitions through which a financial sponsor consolidates ownership. Increasingly, this strategy is shaping economically important markets, but historically, it has escaped antitrust enforcement. We study this phenomenon in the anesthesia industry, site of the first...

This paper uses an aggregative games framework to predict consumer welfare when market structure is endogenously determined. Our main results characterize mergers whose synergies reduce consumer welfare by inducing rivals to exit. The conditions under which such mergers arise are broad,...