Over the past decade, a rapid shift in public attitudes towards large corporations has propelled antitrust law from obscurity to a favourite tool among progressive and conservative populists.1 Several factors account for this rise in antitrust’s political salience, one of which is the remarkable success of a new wave of anti-bigness advocates in attention markets.2 These advocates have branded themselves as 21st-century trustbusters, promoting their anti-bigness agenda as an ‘anti-monopoly movement’. They have adeptly converted their gains in attention markets into political influence and control over antitrust institutions. Their achievements have sparked both optimism and concerns that we might be witnessing an anti-monopoly realignment, with anti-bigness ideologies on the verge of reshaping antitrust policies. This essay explores the plausibility of an anti-monopoly realignment transforming antitrust law and policy. At the core of the anti-bigness movement lies the belief that failed antitrust policies have contributed to, or exacerbated, a wide range of social, economic, and political problems, resulting in ‘excessive market concentration [that] threatens basic economic liberties, democratic accountability, and the welfare of workers, farmers, small businesses, startups, and consumers’, denying the public the ‘benefits of an open economy’, and ‘widening racial, income, and wealth inequality’.3 Building on this premise, anti-bigness crusaders contend that their anti-monopoly agenda will restore competition in the American economy and reverse the trends.