Big Tech today faces unprecedented levels of antitrust scrutiny. Yet antitrust enforcement against Big Tech still faces a major obstacle: the Supreme Court’s 2018 decision in Ohio v. American Express. Popularly called Amex, the case imposed a higher initial burden on antitrust plaintiffs in cases involving two-sided markets. Two-sided markets connect two distinct, noncompeting groups of customers on a shared platform. These platforms have indirect network effects, meaning that one group of customers benefits when more of the second group of customers joins the platform. Two-sided markets are ubiquitous in the technology sector, encompassing social media, search engines, and online marketplaces.

Many have observed that the Amex Court’s reasoning drew on questionable economic principles, contrary to the typical approach in antitrust law. This Note examines and adds to these critiques through a novel analysis of lower-court cases post-Amex. This analysis reveals that Amex has resulted in inconsistencies and confusion in the lower courts, opening the door for technology defendants to manipulate Amex’s definition of two-sided markets for their own benefit. To resolve these inconsistencies, this Note proposes a two-part legislative solution to curb Amex’s reach.