Introduction
On June 5, 2026, the new EU disclosure regime introduced by the EU Listing Act took effect, changing how EU-listed issuers handle inside information during protracted processes while leaving the prohibitions on insider dealing and market manipulation and the definition of inside information untouched. The reforms therefore focus not on the core market abuse offences themselves, but on the procedural framework surrounding those rules, and in particular the Article 17 disclosure regime.
This publication summarises the EU reforms, sets out the unamended UK position, considers the supervisory evidence that may shape future UK reform, and identifies the practical steps dual-listed issuers and their advisers should be taking in the meantime.
The UK Market Abuse Regulation (UK MAR), meaning the version of Regulation (EU) No. 596/2014 (EU MAR) preserved in domestic law under the European Union (Withdrawal) Act 2018, remains in its pre-EU Listing Act form as assimilated law, creating a widening regulatory gap that issuers and their advisers will need to manage.
What the EU has changed
The headline change is to Article 17(1) EU MAR. Provided confidentiality is maintained, issuers are no longer required to disclose inside information relating to intermediate steps in a protracted process, such as ongoing negotiations, board discussions or preliminary approaches; instead, the disclosure obligation is triggered only when the final event or circumstance in the process occurs.
Although the reformed regime took effect on June 5, 2026, the detailed implementing framework is contained in a Delegated Regulation adopted by the European Commission on April 8, 2026, which sets out a non-exhaustive list of final events across categories including business strategy, capital structure, financial reporting and corporate governance, each mapped to the moment at which disclosure is required.
Subject to the three-month European Parliament and Council scrutiny period, that Delegated Regulation is expected to be published in final form and enter into force in Q3 2026. The list of final events does not displace the issuer’s case-by-case assessment of whether information is inside information within the meaning of Article 7 EU MAR, and issuers must still be able to justify their disclosure or non-disclosure decisions to the regulator on request.
An issuer relying on the relaxation must continue to assess at each stage whether information is inside information, maintain insider lists, ensure confidentiality, restrict dealings and be ready to announce immediately on a leak. The longer information is withheld, the greater the operational burden and the greater the risk that a confidentiality breach will trigger immediate disclosure in any event.
The EU has also recalibrated the conditions for delayed disclosure. The limb requiring that delay must not be “likely to mislead the public” is replaced by a test that the withheld information must not be “in contrast” with the issuer’s most recent public announcement on the same matter. Since the Delegated Regulation defines relevant communications broadly, capturing investor presentations, analyst briefings, social media posts and other informal statements, the more frequently and informally an issuer communicates, the narrower the practical scope for delay.
Alongside these headline changes, a set of operational reforms introduced by the EU Listing Act took effect on December 4, 2024, including simplified buy-back reporting, confirmation that Article 11 market soundings operate as an opt-in safe harbour rather than a mandatory regime, higher PDMR reporting thresholds (raised from EUR5,000 to EUR20,000), expanded closed-period exemptions, and a streamlined insider list.
A second Delegated Regulation adopted on April 8, 2026, also expected to enter into force in Q3 2026, completes that package by extending the PDMR closed-period trading exemptions under Article 19(12) EU MAR to financial instruments other than shares and updating the Annex II indicators of market manipulation to address algorithmic trading and correct erroneous cross-references. Individually, these changes are incremental, but collectively they widen the compliance gap with the UK across almost every operational dimension of MAR, and that cumulative divergence frames the questions now facing the UK.
The UK position
None of these changes apply under UK MAR. Article 17(4) UK MAR continues to permit delay only where all three cumulative conditions are met: immediate disclosure would prejudice the issuer’s legitimate interests, delay is not likely to mislead the public, and confidentiality can be ensured. In Primary Market Bulletin (PMB) 52 (November 2024), the regular bulletin published by the UK’s Financial Conduct Authority (FCA), the FCA gave examples of protracted processes, including offer processes, periodic financial information and CEO appointments and resignations, where it considered the disclosure trigger point to fall earlier than many issuers might assume.
On CEO changes, the FCA’s position differs notably from the Delegated Regulation, which ties disclosure to the formal decision of the issuer’s governing body. The UK regulator has therefore been tightening disclosure expectations while the EU was loosening them. PDMR reporting thresholds, closed-period exemptions, market soundings obligations and insider list requirements also remain in their pre-reform scope under UK MAR.
Beyond the substantive gap, the two regimes are also drifting apart in how analogous concepts are interpreted. Two recent judgments of the Court of Justice of the European Union (CJEU) have further refined core EU MAR concepts: Finansinspektionen v. Carnegie Investment Bank AB (C 363/24), decided on March 19, 2026, and Brännelius (C-229/24), decided on April 16, 2026. Together, the rulings clarify aspects of what constitutes “precise” inside information and when inside information ceases to be non-public, and the CJEU confirmed in particular the following:
- Notification that a person has been placed on an insider list does not necessarily constitute inside information but may qualify as such where additional contextual elements are present.
- Disclosure to a limited circle of recipients, or mere availability of information on request under national law, does not satisfy the MAR standard of public disclosure under Article 17 MAR and Implementing Regulation 2016/1055.
Since January 1, 2024, UK courts are no longer required to have regard to retained EU law principles of interpretation and post-Brexit CJEU rulings are not binding in UK proceedings. In practice, however, UK courts and the FCA are likely to continue to draw on CJEU jurisprudence on MAR concepts where the underlying text remains aligned, even though the two regimes will increasingly diverge in how analogous provisions are construed and applied.
Pre-Brexit guidance from the European Securities and Markets Authority (ESMA) remains relevant to the extent it assists with compliance with UK MAR as it currently stands. However, ESMA’s revised MAR Guidelines, expected in Q4 2026 and drafted to reflect the amended EU regime, will have no direct application in the UK.
ESMA's February 2026 consultation proposed deleting from the Guidelines all legitimate interests for delayed disclosure that relate to protracted processes (which no longer require formal justification), adding new categories—including where an issuer is asked not to disclose by a public authority, needs to gather additional information, or is participating in several procurement processes for similar contracts—and removing the sections relating to the now-superseded “not likely to mislead” condition.
The road to UK reform
Reform of UK MAR is a question of when, not if. The 2022 Edinburgh Reforms included a specific commitment to review the wholesale markets framework and the Financial Services and Markets Act 2023 listed UK MAR in Schedule 1 as assimilated law earmarked for revocation and replacement with bespoke UK provisions, whether through HM Treasury legislation or FCA rules. No timetable has been set, but the revocation of the UK Prospectus Regulation on January 19, 2026 shows that the broader programme is already in motion.
Precisely when the FCA will turn to UK MAR is unclear, and neither HM Treasury nor the FCA has publicly indicated the scope or priorities of any future UK MAR reform. However, two recent FCA supervisory exercises offer signals as to the potential direction of travel.
In PMB 59 (October 2025), the FCA reviewed delayed disclosure notifications under Article 17(4) UK MAR for the period from April 2022 to March 2024. The FCA found that notification volumes fell by 39% against the previous period, only 18% of issuers submitted notifications (down from 25%), average delay periods lengthened to 35 days overall and to more than 60 days for M&A transactions, and 43 issuers were flagged for notifying seven or more days late.
Read together, these figures suggest more than administrative slippage: issuers appear increasingly uncertain about when inside information crystallises and, in practice, are delaying for longer and notifying less. That is precisely the uncertainty the EU has now legislated away for protracted processes, and the FCA’s evidence base could support a similar move towards simplification, potentially borrowing from the EU's “final event” model.
The second signal is the FCA’s multi-firm review of market soundings practices among wholesale banks active in UK equity capital markets. The review scrutinised compliance with the prescriptive demands of Article 11 UK MAR—recorded lines, mandatory information sequences and five-year record-keeping—and reads as the regulator testing whether that machinery is proportionate to its benefit.
Given the EU has just confirmed its own soundings regime as an opt-in safe harbour, any UK conclusion that the rules are disproportionate invites an obvious comparison. A reformed UK approach might move towards a more principles-based framework, as the UK has done in its Primary Markets Effectiveness review, focused on outcomes rather than procedural prescription while retaining the core protection against unlawful disclosure.
As the EU regime becomes less burdensome across disclosure, market soundings and PDMR-related rules, the pressure to ensure UK MAR does not disadvantage UK-listed issuers will only grow. Targeted reform of the protracted-process disclosure trigger could be the first move, because the FCA’s own evidence is strongest there and the EU now offers a ready template, with reform of the soundings regime a potential second step.
Wholesale replication of the EU model is unlikely, however, because the UK has signalled through PMB 52 and its takeover-leak commentary that it remains protective of timely disclosure and market integrity, meaning any reform is more likely to pursue proportionality without diluting those protections.
Practical implications
The practical tips below are directed primarily at issuers with securities admitted to trading on both EU and UK venues, whose compliance burden is most acute, with shorter notes for UK-only issuers and for investors with board representation. UK-only issuers remain governed by the unamended UK MAR text and are not required to adapt to the EU reforms.
For dual-listed issuers
The bifurcated analysis required of dual-listed issuers in a protracted transaction is described above, but two further points are worth emphasising in the practical context. First, the Article 17(4) delay remains available for the final event under EU MAR, although it is likely to be invoked far less often given the narrower window in which disclosure is now triggered. Second, the same set of facts may produce different outcomes under the EU's “not in contrast” test and the UK's “not likely to mislead” test, so the conservative course in a dual-listed scenario is to calibrate to whichever standard is stricter on the facts.
Buy-backs add a further complication, because Article 5(3) UK MAR cross-refers to EU MAR reporting requirements that have not been updated for the simplified EU framework. Pending FCA guidance, the safe course is to continue applying the unamended EU MAR reporting fields to UK-listed shares and otherwise to calibrate compliance to the stricter standard at every stage. Against that backdrop, dual-listed issuers should take four steps. First, refresh inside information and delay procedures against the Annexes to the new Delegated Regulation on protracted processes.
Second, if not already done, update PDMR dealing policies to reflect the extension of closed-period trading exemptions under Article 19(12) EU MAR to non-share financial instruments, as confirmed by the second April 8, 2026 Delegated Regulation.
Third, monitor the final ESMA MAR Guidelines expected in Q4 2026, in particular the recalibrated legitimate interests for delay. Fourth, update insider list templates adapted to reflect Implementing Regulation (EU) 2026/1291 and revisit insider list management and information-sharing protocols in light of Carnegie and Brännelius, focusing on the contextual threshold for “precise” information, the Article 17 standard for effective public disclosure and “need to know” restrictions during delay periods.
For UK-only issuers
The EU reforms do not bind UK-only issuers, but three points warrant attention. First, the FCA's commentary in PMB 52 on the disclosure trigger point in protracted processes, including offers, periodic financial information and CEO appointments and resignations, sets a stricter benchmark than many issuers may have assumed. That benchmark should be reflected in disclosure committee playbooks and inside information procedures.
Second, the PMB 59 findings on falling notification volumes, longer average delay periods of 35 days overall and over 60 days for M&A, and late notifications indicate where FCA supervisory focus is likely to fall, and UK-only issuers should therefore test their own delayed-disclosure record-keeping and Article 17(4) decision logs against those benchmarks.
Third, although the Carnegie and Brännelius judgements are not binding in UK proceedings, they are nonetheless likely to inform FCA and UK court interpretation of analogous UK MAR concepts and should be factored into insider-list practices and information-sharing protocols, including responses to regulator and governmental requests.
In summary, UK-only issuers should monitor the UK reform pipeline and actively engage with any FCA consultation since the calibration of UK reform could likely be shaped by issuer evidence on the current regime's operational burden.
For investors with board representation
A nominee director is a person discharging managerial responsibility and the appointing investor will typically be a “person closely associated”, triggering its own Article 19 notification obligations on dealings in the issuer’s instruments.
Investors holding both EU- and UK-listed positions should therefore map dealings against the divergent thresholds and closed-period exemptions—EUR20,000 (with member state discretion) and the broader Article 19(12) and 19(12a) carve-outs in the EU, compared with the unchanged EUR5,000 threshold and narrower exemption in the UK—and should also expect nominees, and therefore their information walls, to sit on undisclosed inside information for longer under the EU’s intermediate-steps relaxation.
Conclusion
The entry into force of the EU's reformed MAR regime marks the most significant point of divergence between the UK and EU market abuse frameworks since Brexit. UK reform will come, because the legislative architecture is in place and the FCA's evidence-gathering is underway, but until then issuers and their advisers must navigate two diverging regimes without certainty as to when or how the UK will respond.
The potential shape of UK reform may address the uncertainties surrounding protracted processes, recalibrate the prescriptiveness of market soundings and respond to the competitive dynamics created by the EU’s reforms, while preserving the market integrity protections at the heart of UK capital markets regulation. Until the UK moves, London-listed issuers and their advisers will carry the heavier compliance load, and the competitive question is how long that asymmetry will be allowed to persist.
