Or Brook (University of Leeds) has posted Do EU and U.K. Antitrust ‘Bite’?: A Hard Look at ‘Soft’ Enforcement and Negotiated Penalty Settlements on SSRN.  Here is the abstract:

EU and U.K. antitrust are contingent upon rigorous enforcement and the imposition of sanctions. Hard enforcement is key; antitrust loses its effect when it does not “bite.” Soft instruments (non-adversarial, informal) and negotiated penalty settlements may be used, but authorities are expected to exercise self-restraint. This article reveals that despite the prevalence of hard-enforcement rhetoric, the vast majority of actions taken by the European Commission (1958–2021) and German, Dutch, and U.K. antitrust authorities (2004–2021) were not fully adversarial. The hard-enforcement actions, moreover, were confined to limited practices and sectors. Despite the prominence of non-fully adversarial instruments in Europe, and in striking contrast to the United States, only limited attention was devoted to their existence and implications. Urging to take a hard look at soft enforcement and negotiated penalty settlements, the article systematically records the enforcement instruments and their particularities, questions their effectiveness, and calls to align enforcement theory to practice.