Harrington (2022) provides a novel theory that explains how a private information exchange involving gross list prices can lead to higher transaction prices. On this basis, he considers that private list price exchanges between competitors should be presumed to harm competition. The theory, which has received much attention in the context of the EU trucks cartel case, was recently referred to by the UK Competition Appeal Tribunal as a “unilateral effects” theory, given that it involves no coordination once list prices have been exchanged. Unlike conventional collusion, the theory does not rely on a monitoring and retaliation mechanism. Given its novelty and relevance for recent competition cases, we consider it useful to explore its potential limitations. We show that both the scope for and magnitude of harm are sensitive to key modelling parameters such as the number of firms, the degree of product substitutability, and the level of marginal cost—sometimes in opposite directions. We also show that there may be no scope for the anticompetitive effect when firms are capacity constrained. Finally, we discuss several additional qualitative aspects that may undermine the theory of harm: the adaptability of internal pricing processes over time, the lack of verifiability of exchanged list price information (especially when the exchange is private), and possible procompetitive or competitively neutral reasons for the conduct. We conclude that, although Harrington provides an insightful addition to the wider literature on the competitive effects of information exchanges, the effects of list price exchanges are not sufficiently unambiguous to justify a general presumption of competitive harm.