We study the 1956 consent decree against the Bell System to investigate whether patents held by a dominant firm are harmful for innovation and if so, whether compulsory licensing can provide an effective remedy. The consent decree settled an antitrust lawsuit that charged Bell with having...

We analyze the effects of the 1984 breakup of the Bell System on the rate, diversity, and direction of US innovation. In the antitrust case leading to the breakup, AT&T, the holding company of the Bell System, was accused of using exclusionary practices against competitors. The breakup was...

How does antitrust enforcement against patent-based monopolies affect innovation? I address this question by empirically studying the US antitrust case against Xerox, the monopolist in the market for plain-paper copiers. In 1975, Xerox was ordered to license all its copier-technology patents in...

While often times the Hypothetical Monopolist Test (HMT) utilized in relevant market delineation is implemented with uniform price increases throughout all the goods in the candidate relevant market, since 1984 the versions of the U.S. Merger Guidelines have emphasized that these small but...

A central motivating factor for studying price markups is their effect on consumer welfare. Reported estimates of (firm-level) price markups in the literature, however, are often focused on industry or cross-country comparisons. These treat different industries equally rather than based on how...

We analyze a large merger in the Dutch banking market during the financial crisis using disaggregated data. Based on a merger simulation model, we evaluate merger-induced changes in the interest rates for savings accounts. We find that the merging banks decreased interest rates by 3 to 5 percent...

We demonstrate how the incentives of firms that partially own their suppliers or customers to foreclose rivals depend on how the partial owner can extract profits from the target. Compared to a fully vertically integrated firm, a partial owner may obtain only a share of the target's profit but...