Within the area of electricity market regulation, a practice has emerged in which the chain of delegation has gone beyond the European Commission, resulting in double delegation. During 2015–2017, the European Commission adopted implementing regulations requiring detailed European terms, conditions and methodologies (TCMs) for electricity markets and system operation to be jointly adopted by national energy regulators. Should the latter fail to agree within a predefined time limit, rule-making would move to the Agency for the Cooperation of Energy Regulators. This rule-making procedure entails that, depending on the dynamic within the procedure, different actors would adopt the TCMs. This article examines how double-delegated rule-making unfolds in a novel and emerging practice, evolving beneath implementing acts. By analysing the factors behind whether TCMs are adopted jointly by national agencies or not, the study investigates whether this form of delegated rule-making in a network setting delivers decisions or whether rule-making by a European Union agency is needed.