SHERIDAN, WYOMING - April 13, 2026 - The Agency for the Cooperation of Energy Regulators (ACER) has published the 43rd edition of its REMIT Quarterly, centering on newly established Rules of Procedure that define the procedural framework for ACER's cross-border investigatory mandate under the EU's wholesale energy market integrity regulation. The publication follows a 2024 legislative update that granted ACER expanded authority, including direct power to investigate cross-border market manipulation cases. With 456 REMIT breach cases under review at the close of Q4 2025, the operational scale of enforcement has grown substantially, making the procedural ruleset a critical reference for compliance and legal teams across European energy markets.
New Rules of Procedure for cross-border investigations
ACER's newly adopted Rules of Procedure establish the step-by-step procedural framework governing how the agency executes its cross-border investigatory mandate under REMIT. These rules were necessitated by the 2024 revision of the REMIT framework, which moved investigatory authority for cross-border cases from national regulators alone to ACER at the EU level. The procedures cover initiation, evidence gathering, coordination with national regulatory authorities, and enforcement steps.
The rules represent the first formal codification of ACER's investigatory process for cross-border cases, filling a governance gap that existed before the 2024 legislative update. Market participants operating across multiple EU member states now face a single, clearly defined procedural standard rather than a patchwork of national investigation approaches. Legal and compliance functions must map their internal processes to these procedures to manage investigation exposure effectively.
Enforcement activity and market surveillance
The 43rd edition provides surveillance data showing 456 active REMIT breach cases under review at the end of Q4 2025. This caseload reflects the breadth of ACER's monitoring activity across European wholesale energy markets and signals continued regulatory pressure on trading conduct. The quarterly also includes a case report on an attempt to manipulate the Spanish gas market, which was investigated and sanctioned by Spain's national energy regulator, the CNMC.
The Spanish gas market case illustrates the functioning of the two-tier enforcement model, where ACER's cross-border oversight complements national regulatory action. Market surveillance statistics in the quarterly additionally show a year-on-year increase in trading volumes on Organised Market Places, driven specifically by growth in natural gas forward markets. This rising volume expands the surface area that regulators must monitor and increases the compliance burden for market operators scaling their trading activity.
Data reporting obligations and stakeholder engagement
ACER's 2026 stakeholder engagement plan features prominently in the quarterly, alongside ongoing preparatory work on data reporting requirements under the revised REMIT. That preparatory work remains pending the finalisation of the revised REMIT Implementing Regulation, meaning reporting obligations are not yet fully settled but are advancing toward implementation. Firms should treat current preparatory guidance as the operative framework for system and process readiness.
The quarterly references takeaways from November 2025 events, including Expert Group meetings on Wholesale Energy Market Data Reporting and the ACER-European Commission REMIT workshop. These forums provided technical input that informs the agency's upcoming public consultation on a new guideline covering REMIT transaction reporting. The consultation will address evolving obligations introduced by the revised REMIT, with scope and timeline details to follow from ACER. Compliance and IT teams responsible for trade reporting infrastructure should monitor this consultation closely, as it is expected to trigger reporting system adjustments.
Business impact
Compliance officers and legal counsel at energy trading firms operating across EU borders must immediately assess internal investigation-response protocols against ACER's newly published Rules of Procedure. With 456 breach cases active at year-end 2025, the probability of a firm receiving an ACER inquiry has materially increased, and the Rules of Procedure now define the legally binding procedural sequence to which firms must respond. Compliance teams that have not mapped their escalation and document-preservation workflows to ACER's framework face procedural risk in any cross-border investigation scenario.
Energy trading operations managers and regulatory affairs directors face two parallel 2026 planning requirements: adapting transaction reporting infrastructure to the forthcoming ACER guideline on REMIT transaction reporting, and preparing for the finalisation of the revised REMIT Implementing Regulation on data reporting. Both outputs will require system changes and potentially new data fields or reporting frequencies. Firms active in natural gas forward markets, where trading volumes are growing year-on-year on Organised Market Places, carry heightened surveillance exposure and should prioritise REMIT compliance investment in their 2026 technology and operations budgets.