Should the FTC have allowed Zillow to acquire its foremost rival, Trulia? It is increasingly well-accepted that digital platforms tend toward dominance in their immediately adjacent relevant-product markets. Google, for example, has long held a majority share of the markets for general-search...

Because market definition is frequently outcome determinative, it is both a central and contested part of antitrust litigation. Recognition of business methods known as multisided platforms presents the challenge of whether and how to incorporate their characteristically interconnected groups...

Platforms, or two-sided markets, have become a topic of significant discussion in competition law over the past decade, culminating in the recent US Supreme Court decision in Ohio v. American Express Co. This note discusses externalities in platforms. Indirect network effects, one type of...

Digital platforms such as Amazon Marketplace or Google Search are commercial and political actors. They have taken center-stage as new spaces for exchange. They facilitate digitally networked interactions and transactions between different customer groups through algorithms, data, and other...

There is widespread concern that dominant platforms may be undermining competition by discriminating against rivals in adjacent markets, such as by refusing to let rival sellers use their platforms or by engaging in “self-preferencing.” Such acts fall within a category of unilateral conduct...

In 2013, I served as a court-appointed expert in consolidated class and individual plaintiff antitrust litigation against Visa and Mastercard in the Eastern District of New York. The litigation involved a challenge to default interchange fees established by Visa and Mastercard, and to certain...

Platform pricing may be connected to antitrust risks, which a company can face under excessive or predatory price scrutiny when the platform is recognized as dominant in the market. Since Federal Antitrust Service of Russia (FAS Russia) prefers price-cost comparison when studying excessive or...

We propose an analysis of platform competition based on the academic literature with a view towards competition policy. First, we discuss to which extent competition can emerge in digital markets and show which forms it can take. In particular, we underline the role of dynamics, but also of...

The most pressing debates in antitrust today center on major platforms like Amazon, Google, and Facebook. Platform markets are subject to strong network effects, which tend to create barriers to entry and reinforce market power. Frequently, the only way for a new platform to enter the market...

Digital platforms, empowered by artificial intelligence algorithms, facilitate efficient interactions between consumers and merchants that allow the collection of profiling information which drives innovation and welfare. Private incentives, however, lead to information asymmetries resulting in...