We analyze horizontal mergers when the acquirer holds a passive partial ownership stake (PPO) in the target firm prior to the merger. We show that a PPO reduces the minimal synergy level necessary to make a merger beneficial for consumers. It follows that an antitrust authority ignoring existing...

A great merger wave occurring in the United States between 1897 and 1903 was the single most important event in a process that yielded the pattern of managerial control and dispersed share ownership which currently distinguishes America's corporate economy from arrangements in most other...

The prohibition of certain types of anticompetitive unilateral conduct by firms possessing a substantial degree of market power is a cornerstone of competition law regimes worldwide. Yet notwithstanding the social costs of monopoly modern legal regimes refrain from prohibiting it outright....

The analysis of unilateral effects in horizontal mergers — especially on markets for differentiated goods — can take into consideration the extent to which the merging firms are close competitors. The elimination of a close competitor can result in an upward pricing pressure (UPP) on the...

We show how temporary ownership by private equity firms affects industry structure, competition and welfare. Temporary ownership leads to strong investment incentives because equilibrium resale prices are determined by buyers incentives to block rivals from obtaining assets. These incentives...

Should there be limits on startup acquisitions by dominant firms? Efficiency requires that startups sell their technology to the right incumbents, that they develop the right technology, and that they invest the right amount in R&D. In a model of differentiated oligopoly, we show distortions...

Should internet era merger policy differ from industrial era merger policy? Platform ecosystems rely on economies of scale, data-driven economies of scope, high-quality algorithmic systems, and strong network effects that frequently promote winner-take-most markets. Their market dominance has...

The antitrust laws of the United States have, from their inception, allowed firms to acquire significant market power, to charge prices that reflect that market power, and to enjoy supra-competitive returns. This article shows that this policy, which was established by the U.S. Congress and...

By serving as a key revenue source for online content providers, online advertising has been instrumental in the development of innovative websites. Continued innovation among content providers, however, depends critically on the competitive provision of online advertising. Suppliers of online...

Estimating antitrust risk is fundamental to identifying, proposing, and pricing deals. A more informed understanding of what to expect when meeting with agency staff and leadership will help antitrust lawyers and economists (or other consultants) anticipate the critical questions and potential...