Defendants in private competition claims have typically relied on individually appointed economic experts. However, the Competition Appeal Tribunal’s 2023 judgment in Stellantis v. Autoliv marked the first instance where all defendants were required to share a single economic expert. This article examines the evolution of expert evidence in English civil litigation, the case management of economic evidence in competition cases, and the implications of the Tribunal’s and Court of Appeal’s rulings on single joint experts. The article concludes by assessing the broader impact of this shift on multi-defendant (and multi-claimant) claims, including collective proceedings.