The year 2025 marked the collapse of the major net-zero financial alliances. Since their creation, these forms of cooperation in capital markets have been subject to antitrust scrutiny, which varies significantly across jurisdictions. In the US, such alliances have been assessed as potential anticompetitive boycotts of the fossil-fuel industry, triggering investigations and litigation that has generated substantial legal uncertainty. Although the EU and the UK have adopted more accommodating approaches, divergences persist even from an intra-European perspective, both regarding the classification of net-zero coalitions and the assessment of out-of-market efficiencies. Through a comparative analysis of US, EU and UK, the paper argues that divergent antitrust approaches can significantly undermine sustainable finance initiatives, producing a serious chilling effect. To reduce this antitrust fragmentation, the paper underscores the importance of recognising broad out-of-market efficiencies and proposes a graduated assessment calibrated to the global benefits of sustainability agreements in capital markets. Against this backdrop, the use of soft law and greater international convergence between competition authorities may offer a viable path forward, although competition law must ultimately grapple with the varieties of capitalism.
World Competition