The “Monopoly Broth” Theory Is a Recipe for Bad Antitrust Law

Competition enforcement in the United States is at an inflection point. Amid growing political pressure to rein in large technology companies, enforcers and private plaintiffs have begun reviving an expansive and legally dubious antitrust doctrine - one threatening to undermine the principled framework courts spent decades constructing.

What the Theory Says

The "monopoly broth" theory of antitrust holds that a company can be found liable for monopolization by combining multiple lawful business acts - such as price cuts or acquisitions - if those actions, in the aggregate, can be said to harm competition and were undertaken with anticompetitive intent. There is no requirement that a single act needs to independently violate any recognized legal standard. Instead, plaintiffs invite courts to treat an assortment of ordinary competitive conduct as collectively unlawful based on the alleged anticompetitive purpose animating those actions.

The theory is not new. Plaintiffs began invoking it as a way to circumvent specific conduct-based tests almost as soon as the courts put them in place. Its revival today is driven less by legal merit than by litigation convenience: a desire to avoid proving that any particular conduct actually crossed a legal line.

Why It Fails as a Matter of Law

Over decades, courts have developed precise, conduct-specific tests - such as for predatory pricing, exclusive dealing, and refusals to deal - because different conduct carries different risks of competitive harm and of false positives. Where established tests exist for a particular type of conduct, plaintiffs must satisfy them before evaluating what, if any, synergistic effect the challenged conduct had. Shortcuts that go straight to a "cumulative effects" bottom line are prohibited.

The monopoly broth theory inverts this logic. It allows plaintiffs to blend acts that each independently fail to meet the threshold for unlawfulness, arguing that combining them can result in liability. The arithmetic is as legally incoherent as it sounds - a series of zeros does not, and should not, sum to a violation.

The theory also conflicts with established Supreme Court precedents. In cases like Pacific Bell v. linkLine and Brooke Group v. Brown & Williamson Tobacco, the Court made clear that lawful conduct cannot be transformed into anticompetitive behavior through aggregation, and that at least one of the relevant acts must be independently anticompetitive to result in liability. Embracing monopoly broth means asking lower courts to disregard this precedent.

Why It Fails as a Matter of Policy

The policy consequences are equally troubling. Antitrust law depends on predictability. Firms making pricing decisions, product investments, and partnership agreements need to know the rules in advance. The monopoly broth theory makes it difficult for businesses and their advisors to discern when ordinary competitive conduct might trigger antitrust liability. That uncertainty distorts business behavior in real-time, discouraging the vigorous competition that benefits consumers and that antitrust law aims to protect.

The chilling effect is particularly acute because the conduct swept into monopoly broth claims, by definition, is lawful when viewed in isolation. Above-cost price reductions, unilateral product improvements, and unconditional refusals to deal with rivals are all legitimate forms of competition. The theory's greatest danger is that it sweeps procompetitive conduct into a dragnet of liability, punishing firms for actions that are entirely lawful in isolation. When companies cannot reasonably distinguish between aggressive competition on the merits and conduct that creates antitrust exposure, the rational response will be to compete less vigorously, harming both consumers and the broader economy.

The Existing Framework Is Adequate

Proponents argue that sophisticated monopolists can evade liability by ensuring no single act crosses a legal threshold. That concern is not unfounded, but the answer is the rigorous application of existing doctrine, not its abandonment. Courts already possess well-developed tools to tackle predatory pricing, exclusionary bundling, and unlawful refusals to deal. The existing antitrust framework is more than adequate to remedy harmful conduct; expanding liability through the monopoly broth theory is unnecessary and ill-advised.

The goal of antitrust law is to protect competition, not to make enforcement easier. Excusing plaintiffs from having to prove independently unlawful conduct would not sharpen the law - it would untether it from principle altogether.