They introduced legislation in October 2021 aimed at prohibiting the practice. Amy Klobuchar (D-MN) and Chuck Grassley (R-IA). The latest example of such weaponization of self-preferencing by antitrust populists is provided by Sens. To indiscriminately prohibit the widespread practice of self-preferencing without considering its benefits would distort competition, not reinvigorate it. Yet, despite the overwhelmingly positive effects of self-preferencing on strengthening competition, antitrust populists aim to weaponize self-preferencing to target only a few companies, while allowing self-preferencing for the rest of the economy. The antitrust literature acknowledges the proconsumer, procompetitive effects of self-preferencing. In addition, antitrust populists use their critique of self-preferencing to bolster their case for a structural separation of platforms (i.e., breakup) or, slightly less radically, for functional separation of the platform (i.e., requiring the platform business to be operated separately from the product sales business). The critique has materialized under the new moniker of “self-preferencing.” It holds that antitrust should prohibit Internet platforms from favoring their own products and services, even if such prohibition improves consumer welfare. The Regulatory Framework of Self-PreferencingĪntitrust populists, in their desire to reduce the size of large companies and protect competitors-especially small businesses-rather than consumers, argue that Internet platforms should not be allowed to promote their own products and services. Toward a Useful Antitrust Distinction: Two Types of Self-Preferencing Why Self-Preferencing Is a Common Business Practice How Self-Preferencing Has Gained Antitrust Prominence