Polar Opposites: Judgments and Counterfactuals in Sainsbury’s V. Mastercard and Asda V. Mastercard

This article explores the recent cases Sainsbury’s v. Mastercard and Asda v. Mastercard and uses them to demonstrate how the decentralization of Article 101 TFEU enforcement is creating legal uncertainty due to national courts being unequipped to apply complex Ex Post counterfactuals consistently. It considers the distinction between restriction of competition by object and restriction of competition by effect to show that EU and national courts now apply the latter. It then considers the requirements for effects-based analysis, focussing on the mandatory use of Ex Post counterfactuals, highlighting their emergence as a legal mechanism in Article 101 application. This article argues that Ex Post counterfactuals’ basis in vague economic theory creates significant difficulties for national courts attempting to enforce Article 101 consistently and evidences these difficulties by considering the courts’ composition, their overreliance on expert economic witnesses, the standard of proof, complex court interplay and referral for preliminary ruling. Ultimately, it argues that despite procedural tools being provided to national courts to ensure consistent application of Article 101 at national and EU levels, the courts are failing to utilize them, resulting in the creation of significant legal uncertainty as evidenced by the polaropposite judgments reached in the Mastercard cases.