TRUM 8.0, stricter validation, new correction deadlines and the second reporting wave: what market participants need to know and when
On 5 November 2026, ACER held its joint webinar on data reporting for Registered Reporting Mechanisms (RRMs), Inside Information Platforms (IIPs), Organised Market Places (OMPs) and AEMPs.
The agenda covered the second wave of the revised REMIT reporting framework, the upcoming guidance on the Delegated Regulation and the reorganisation of ACER’s communication channels. Below we summarise what matters for market participants who report their transactions under REMIT.
Note: Several points presented by ACER are still proposals or consultation results. Where a decision is not final, we say so.
On 29 October 2026, ACER published the first wave of revised reporting documentation: the Transaction Reporting User Manual (TRUM 8.0), updated Q&As and the Guideline on REMIT Transaction Reporting, new Guidance on Exposure Reporting and new and updated electronic formats (XSD).
TRUM 7.0 remains applicable until 29 October 2027, when the new rules take effect. Key changes include Exposure Reporting, revised LNG reporting, changes to Tables 1–4 and new rules for certain bilateral contracts with energy-intensive consumers.
ACER confirmed that new XML trading examples for the updated Annex II are in preparation and are expected around mid-2027, once the schemas are final. Since that leaves limited time, we recommend starting your internal preparations now rather than waiting for the examples.
According to ACER’s consultation results, around 75 of 161 validation rules are proposed to be active by October 2027: 60 of 84 existing rules and 15 of 77 new rules. The final list is still being assessed.
Some of the proposed rules check reported data against external references such as market participant registers and EIC code lists. ACER has not yet decided which of these checks will be mandatory.
What this means for you: make sure your ACER codes, EIC codes and other master data are accurate and up to date.
ACER also asked reporting parties to avoid the value “Other” where possible. If you are unsure which value applies to a field, the REMIT Query Form is the right channel, and we are happy to support you with it.
Under the Delegated Regulation, records rejected by ACER must be corrected and resubmitted within fixed deadlines:
| Error attributable to | Deadline for correction and resubmission |
|---|---|
| The RRM | 5 working days |
| The RRM’s client | 10 working days |
Your RRM notifies you of the error and explains it. You provide the corrected data, and the RRM resubmits it to ACER as quickly as possible. ACER may extend the deadline in justified cases; the exact procedure for requesting an extension is still being discussed.
ACER will not publish general criteria for deciding who caused an error, because this depends on each RRM’s systems and its relationship with its clients. Clear processes between you and your RRM are therefore key.
The second wave extends REMIT reporting to further data types:
| Area | What is planned |
|---|---|
| Electricity balancing | Reporting of balancing transactions |
| Capacity mechanisms | Transactions under capacity mechanisms, including the central buyer model |
| Gas storage | Gas storage contracts |
| Trade-matching systems | Transactions on trade-matching systems used by two or more OMPs (Table 5) |
| Fundamental data | Electricity and gas infrastructure data, LNG and gas storage facilities |
| Inside information | Inside information published on IIPs |
Two new manuals will replace the current Manual of Procedures: the Fundamental Data Reporting User Manual (FRUM) and the Inside Information Reporting User Manual (IRUM).
This wave is especially relevant for TSOs, SSOs, LNG operators and balancing service providers. ACER also explained that TSOs and SSOs can qualify as OMPs, with the obligations that come with that status, for example when they run capacity auctions or other order-matching mechanisms. What counts is the actual activity, not the type of entity.
| Date | Milestone |
|---|---|
| 16 Nov 2026 – 15 Jan 2027 | Phase 2 consultation, round 1 |
| 23 Nov 2026 | ACER public webinar on Phase 1 documentation |
| 3 Dec 2026 | ACER joint webinar on FRUM, IRUM and Phase 2 |
| 14 Jan 2027 (tbc) | Next ACER joint webinar |
| 15 Feb – 12 Mar 2027 | Phase 2 consultation, round 2 |
| 29 Apr 2027 | Publication of final Phase 2 documentation |
| 29 Oct 2027 | Phase 1 go-live |
| 29 Apr 2028 | Phase 2 go-live |
ACER will run four topic-based surveys via EU Survey:
| Survey | Topic |
|---|---|
| 1 | Trade-matching systems (Table 5) |
| 2 | Gas: transactions, fundamental data and validation rules |
| 3 | Electricity: transactions, fundamental data and validation rules |
| 4 | Inside information, including validation rules |
Guidance documents and validation rules will be consulted in two rounds. Comments on electronic formats (XSD) can only be submitted in the first round. Comments may be up to 10,000 characters, supporting files can be uploaded, and ACER is looking into allowing answers to selected sections only.
Contact: REMIT.consultations@acer.europa.eu
Under the new Delegated Regulation, all RRMs must be authorised by ACER, and existing RRMs must apply by 29 April 2028. We are already preparing for this so that your reporting continues without interruption.
The new rules also set clear service standards. Clients must be notified of planned maintenance at least five working days in advance, and service disruptions must be reported to ACER within 24 hours.
Review the TRUM 8.0 changes that apply to your contracts, especially Exposure Reporting, LNG and bilateral contracts, and plan your implementation ahead of 29 October 2027.
Check that your ACER codes, EIC codes and other master data are correct, and make sure you can respond quickly when we notify you of a rejected record.
If you are a TSO, SSO, LNG operator or balancing service provider, assess whether Phase 2 applies to you and consider taking part in the consultation from 16 November 2026.
Questions about how these changes affect your reporting? Our team is happy to help. Contact us
Note: This summary has been compiled from ACER’s webinar of 5 November 2026 and related publications and reflects our understanding. It is provided for informational purposes only and is not legally binding. We do not take any legal responsibility for the accuracy or completeness of the information. For legal or regulatory matters, please refer to the official ACER documentation.