Scholars and antitrust enforcers have raised concerns about anticompetitive effects that may arise when institutional investors hold substantial stakes in competing firms. Their concern rests on empirical evidence that such common concentrated ownership is associated with higher prices and lower...

Some scholars have argued that the phenomenon known as common ownership, which refers to an investor's simultaneous ownership of small stockholdings in several competing companies, is anticompetitive and prohibited by the U.S. antitrust laws. These proponents target in particular large...

Partial ownership of stock in multiple competing firms is an important scholarly and policy topic in both corporate and antitrust law. Until now, the discussion has focused on ownership. This essay shifts the debate from a focus on common ownership to a focus on common control. No prior work has...

Minority shareholdings have been on the regulatory agenda of competition authorities for some time. Recent empirical studies, however, draw attention to a new, thought provoking theory of harm: common ownership by institutional investors holding small, parallel equity positions in several...

A phenomenon known as “Common Ownership” arises when shareholders hold substantial stakes in competing firms. Although recent empirical evidence has illustrated how common concentrated owners are associated with higher product market prices and lower output, scholars remain divided as to the...

Horizontal shareholding exists when significant shareholders have stock in horizontal competitors. (It is often imprecisely called "common shareholding," but that term can also apply when shareholders own stock in two noncompeting corporations. It differs from "cross-shareholding," which...

This Article shows that new economic proofs and empirical evidence provide powerful confirmation that, even when horizontal shareholders individually have minority stakes, horizontal shareholding in concentrated markets often has anticompetitive effects. The new economic proofs show that,...

When successive monopolies transact through noncooperative linear pricing, the resulting double markup decreases their joint profits relative to vertical integration. However, if there are downstream rivals (which are not double marginalized), the same noncooperative interaction often...

We study the design of online platforms that aggregate information and facilitate transactions. Two different designs can be observed in the market: revealing platforms that disclose the identity of transaction partners (e.g. Booking) and anonymous platforms that do not (e.g. Hotwire). To...