ACER, an EU Agency, is entrusted with oversight of trading on Europe’s wholesale energy markets. In 2025, 19.9 bn transactions data was reported to ACER.

Data quality, transparency and confidentiality are cornerstones of our work. We adhere to international standards on how we collect, protect and publish data.

ACER provides evidence of the data quality assessments either by publishing dedicated open letters or via its REMIT quarterlies.

ACER strives to ensure that all collected data is complete, accurate and submitted in a timely way. Our data quality checks follow a two-step approach​:

1. Data validation 

​When data is submitted in a data record by reporting entities to ACER's REMIT Information System (ARIS), automatic validation occurs at two levels:

• technical validation: making sure all data fields in the data record are complete and in the correct format; and
• database validation: ensuring reported data is consistent with reference data.

Any invalid or inconsistent data record is rejected and flagged, ensuring that only information succeeding the preliminary screening is stored in ACER's REMIT database. 

2. Quality assessment 

​After data is collected, ACER's analysts conduct additional quality checks to confirm that it is accurate, complete and reliable, and follow up on any detected issues.

This section outlines why we in ACER collect energy data (our legal mandate), what energy data we collect, how we do it (data reporting) and how we ensure high data quality (through rigorous checking procedures) and confidentiality.

Two key features distinguish ACER from other energy data sources: 

1. our legal standing as an EU Agency; and 
2. our mandate in monitoring and assessing trading activities and in building trust in the integrity of EU energy markets.

REMIT is the EU-wide framework that protects wholesale energy markets from abuse, ensuring open and fair competition. Under the REMIT Regulation, ACER is mandated to collect data to monitor and assess trading activities on wholesale energy markets across the EU.

This EU-wide oversight of every trade in energy wholesale markets is unique to ACER. Working closely with national regulatory authorities (NRAs), we detect potential market abuse (such as insider trading and market manipulation). This supports market integrity, transparency and fair price formation.

Beyond its REMIT mandate, ACER also collects other data on wholesale and retail energy markets (e.g. under the electricity Capacity Allocation and Congestion Management (CACM) Regulation) to support its broader monitoring.

ACER and national regulatory authorities (NRAs) work closely together to protect energy markets from abuse. Increased transparency and monitoring build confidence that energy markets work well for EU businesses and citizens and that prices are determined in a fair way.

The rules for reporting energy market data to ACER are set out in the REMIT Implementing Regulation. Following the 2024 revision of REMIT, the Implementing Regulation has been updated in 2026 to include:

• new quarterly ‘exposure’ reporting, which requires market participants to report their trading positions (i.e. showing how exposed they are to future energy price movements over the next 18 months);
• new reporting elements for algorithmic trading and Direct Electronic Access (DEA);
• a clarified definition of obligations for ‘organised market places’ (OMPs) and other reporting parties; 
• extended reporting obligations for Liquified Natural Gas (LNG) and hydrogen transactions; and
• the introduction of ‘periodic data reporting’ (e.g. for balancing processes).

Based on these rules, ACER sets the procedures, standards and electronic formats (including reporting manuals such as the Transaction Reporting User Manual) that market participants must follow when submitting data. This centralised and structured system supports consistent data collection and effective market monitoring.

A full list of relevant documents is available on the REMIT Documents page.

To fulfil its mandate, ACER collects several types of data, including: 

• Transaction data: Records of trades and orders to trade relating to wholesale energy products, either traded on 'organised market places' (OMPs) or bilaterally. The wholesale energy product definition encompasses supply, transportation capacity allocation and storage of electricity, natural gas and hydrogen. This includes information on product type, quantity, price, delivery date, counterparty and beneficiary.
• LNG market data: Information about LNG transactions, used for both market monitoring activities and related ACER’s functions (including publication of its daily LNG price assessment and benchmark).
• Inside information: Market-sensitive information that must be publicly disclosed under REMIT, so that all market participants receive it transparently and at the same time. This concerns events that may affect wholesale energy prices (such as planned outages, unavailability, reduced capacity, maintenance delays or other events affecting production, storage or transmission). 
• Fundamental data: Information about energy assets, such as capacity and use of facilities for the production and storage of electricity, gas, LNG and hydrogen, including storage levels, consumption, transmission and generation outputs, as well as planned or unplanned outages.

ACER may request additional information or clarifications from market participants and reporting parties if the data submitted is incomplete or unclear. Reporting parties are responsible for submitting complete, accurate and timely data in line with the legal requirements and reporting arrangements.

​​​Since the entry into force of the European Commission's Implementing Regulation, market participants and third parties acting on behalf of market participants are obliged to provide ACER with a record of their wholesale energy market transactions, including orders to trade.

ACER registers market participants and third parties reporting on their behalf as registered reporting mechanisms (RRMs) to ensure efficient, effective and safe exchange and handling of information. ​

Find out more about the process of data collection and data reporting.

​Roundtable meetings

​To discuss the views and practices of the reporting parties on REMIT data collection, ACER regularly organises Roundtable meetings in Ljubljana. These meetings are attended by: 

• Associations of energy market participants (AEMPs)​: AEMPs represent registered market participants in communication with ACER during Roundtable meetings.
• Inside information platforms (IIPs)​: IIPs enable market participants to share inside information with the wider public, in accordance with the minimum quality requirements listed in the ACER Guidance.
• Organised market places (OMPs)​: OMPs include electricity and gas exchanges, brokers and other persons professionally arranging transactions, and trading venues.
• Registered reporting mechanisms (RRMs​): RRMs represent all registered reporting entities, and include market participants, OMPs, ENTSOs, and third party reporting on behalf of entities under the data reporting obligation. ​​

Webinars

​To dynamically address any operational topics and ad hoc issues the reporting parties may be facing, ACER also holds periodic webinars with RRMs and OMPs.

These webinars are organised on ad-hoc basis, and the attendees can propose discussion topics via dedicated forms.

​Public consultations

ACER regularly launches public cons​ultations​ to invite all interested parties to provide their views on specific data collection issues.

Access ACER closed public co​​nsultations​.

ACER works closely with many bodies (including reporting parties, stakeholders and institutions) to ensure the effective implementation of REMIT.

Who do we cooperate with?

• National regulatory authorities (NRAs).
• Other relevant national authorities (e.g. competition authorities, financial regulators).
• European institutions and agencies (e.g. European Commission, European Securities and Markets Authority (ESMA)).
• Reporting entities: 
  • Associations of energy market participants (AEMPs): Registered market participants that have established cooperation with ACER (via AEMP Open call).
  • Inside information platforms (IIPs): Platforms that enable market participants to share inside information with the wider public (in accordance with minimum quality requirements listed in ACER's Guidance).
  • Organised market places (OMPs)​: Electricity and gas exchanges, brokers, persons professionally arranging transactions and trading venues.
  • Registered reporting mechanisms (RRMs): All registered reporting entities, including market participants, OMPs, European Networks of Transmission System Operators (ENTSOs) and third parties reporting data on behalf of other entities. ​​
• REMIT subject matter experts (through dedicated Expert Groups).
• Academia and institutions.
• Other stakeholders.

ACER also engages in international cooperation.

ACER engages widely on REMIT implementation (e.g. on the revision of related guidance), including through:

• public workshops, webinars and events (e.g. annual REMIT workshop);
• roundtable meetings with data reporting parties;
• public and targeted consultations;
• bilateral exchanges (e.g. through the Market Surveillance Forum (MSF) and the Energy Trading Enforcement Forum (ETEF)); and
• Memorandums of Understanding (MoUs) (e.g. with NRAs, ESMA, OMPs and the US Federal Energy Regulatory Commission (FERC)).

While the MoU with the NRAs is a multilateral one, MoUs with OMPs are bilateral. This allows OMPs to set out the content and procedures for the cooperation on more specific issues related to market monitoring under REMIT. ACER had signed MoUs with eight organised market places across the European Union.  ​

REMIT prohibits market manipulation and insider trading in the wholesale energy markets, as well as imposing several obligations. Both can eventually lead to a sanction.

ACER strongly cooperates with the relevant NRAs to monitor the wholesale energy markets and effectively sanction REMIT breaches.

The table below gives an overview of decisions and sanctions of REMIT breaches:

Note:

Article 3 (insider trading)

Article 4 (non-disclosure of inside information)

Article 5 (actual or attempted market manipulation)

Article 8 (non-reporting of info to ACER)

Article 9 (non-registration)

Penalties for breaches of REMIT are imposed at national level in line with Article 13 of REMIT. 

Article 18 of REMIT establishes that the rules on penalties for breaches of Article 3 and 5 of REMIT are established by the Member States. The implementation regime is therefore different across Member States and some breaches of REMIT may be sanctioned under national provisions. Please consult the sources for the status of the proceedings and more information on the Decisions.

* This amount includes both the (i) fine and (ii) confiscated profit.​​​

** The fines expressed in other currency than EURO are converted in EURO using the ECB exchange rate on the day of the Decision.

*** This amount constitutes a committed reimbursement, not a fine.

ACER ensures that national regulatory authorities (NRAs) carry out potential REMIT breach case reviews and investigations in a coordinated and consistent way.

To do this, it cooperates closely with NRAs, the European Securities and Markets Authority (ESMA), the competent financial market authorities of the Member States and, where appropriate, national competition authorities. It also maintains strong links with major organised market places and engages in international cooperation​.

ACER's involvement in market abuse cases, through triaging and reviewing cooperation needs, has been steadily intensifying and becoming more and more frequent. ACER interacts on REMIT cases more than 500 times per year, mostly by reviewing documents and processing requests, ensuring a coordinated and consistent approach.

In 2024, the revised REMIT framework expanded ACER’s mandate to include investigating suspected REMIT breaches that affect multiple EU countries. See ACER's Rules of Procedure on how cross-border investigations are conducted.

ACER's coordination activities on REMIT breach cases, combined with the NRAs' strong commitment, have already delivered visible results. 

Fines for over 230 million EUR were imposed to sanction market abuse in wholesale energy markets across the whole EU. 

​​​REMIT protects the integrity of wholesale electricity and gas markets by reducing instances of market abuse and increases the EU consumers' confidence in market outcomes. 

Market abuse can be either market manipulation or insider trading.

REMIT prohibits market participants to engage in or attempt market manipulation​. This includes performing fa​​​lse or misleading transactions, price positioning which secures or attempts to secure the price at an artificial level, as well as transactions involving fictitious devices or deception, and the dissemination of false and misleading information.

REMIT prohibits using or disclosing inside information​ or recommending other persons to use inside information – with few strict exemptions. ​

Market abuse is enforced at national level by energy regulators. When cases involve multiple EU countries, ACER can carry out cross-border investigations under the revised REMIT framework. ACER's Rules of Procedure explain how these investigations are conducted.

When you suspect a breach of REMIT, do not hesitate to report this through the Notification Platform​.

The first figure shows the stock of potential REMIT breaches under assessment by NRAs at the end of each year.

The second figure shows the type of REMIT breaches reported to or by the Agency as a percentage over the total number of potential REMIT breaches reported.

The map shows the number of ongoing potential REMIT breach cases under assessment per Member State.