A structural shift in how ESMA calibrates the MiFIR transparency regime has handed Approved Reporting Mechanisms (ARMs) a more central role in market data infrastructure than they have held since MiFID II went live in 2018. Under the simplification programme tied to the MiFIR Review, ESMA has discontinued the dedicated reporting flows on which transparency thresholds and volume cap calculations have relied for the past eight years, switching to the Article 26 transaction data already submitted via ARMs. Volume cap reporting ended on 31 December 2025; FITRS quantitative data on equity instruments, bonds, structured finance products and emission allowances ended on 31 March 2026.
The launch of the Approved Reporting Mechanism Association (TARMA) on 29 April, with Bloomberg Data Reporting Services, LSEG Regulatory Reporting Solutions and MarketAxess Post-Trade as founding members, is the institutional consequence. All three remain members of APARMA, whose executive committee narrowed its own focus to APAs alone in August 2025. The split is structural specialisation rather than a breakaway, but the timing is not coincidental.A quiet rerouting of the transparency regime
The change ESMA set out in public statements in February and October 2025 has both straightforward mechanics and far-reaching consequences. Since 2018, the EU’s transparency and volume cap regimes have been fed by data that trading venues report to ESMA specifically for those purposes, channelled through the Financial Instruments Transparency System (FITRS) and the dedicated double volume cap reporting flow. Both calculations are now derived instead from the transaction data investment firms already submit to national competent authorities (NCAs) and ESMA under Article 26 of MiFIR.
Article 26 reporting is the ARM channel. ARM data, originally submitted to support supervisory monitoring of market abuse, now also serves as the operational basis on which transparency thresholds and the single volume cap – which replaced the double volume cap mechanism in January 2026 – are calibrated. ARM data quality has direct downstream consequences for how the transparency regime functions across European markets.
Jose Navarro, CEO of Regulatory Reporting BV at LSEG and the first chair of TARMA, points to a corresponding intensification of supervisory engagement on data quality. “More broadly on data quality, we’re seeing increasing regulatory focus on the accuracy and consistency of reported data fields,” he tells TradingTech Insight. “As usage expands, supervisors are rightly raising more queries to ensure data integrity across the reporting chain.”
APARMA itself acknowledged the shift in its September 2025 response to the FCA’s CP25/20 consultation, noting that the association was “mindful of ESMA’s plan to remove EQU/ETR reporting in favour of using transaction reporting for transparency calculations.” The submission stayed within APA-side issues, but the parenthetical confirms that the publication-side body had recognised the regulatory weight moving onto the transaction-side channel.
Why a dedicated body, and why now
Navarro positions TARMA’s formation as the natural conclusion of two convergent pressures: a regulatory simplification agenda focused on burden reduction in both the UK and EU, and the recognition that the joint APA-and-ARM model that made sense in 2022 had been overtaken by divergent activity weights on each side.
“Discussions tended to focus more on APA activity, with fewer opportunities to address ARM topics,” Navarro says. “Hence TARMA was established to provide a dedicated forum and governance structure to discuss issues most pertinent to ARMs.” APARMA’s executive committee formally narrowed its focus to APAs alone with effect from 1 August 2025; the eight-month gap before TARMA’s launch reflects, on Navarro’s account, the practical work of standing up a new trade association.
The institutional rationale for a dedicated body, rather than continued bilateral engagement, rests on access. Trade associations get invited to working groups and the rule-shaping forums where regulators do their detailed work; bilateral engagement does not scale across the regulatory community in the same way.
APARMA’s membership has reshuffled around the split. Of the six 2022 founders, Euronext is no longer listed; Nasdaq Nordic has joined as an APA-only member. Euronext operates a pan-European ARM and is not currently listed as a member of either body, though Navarro confirms TARMA has reached out to other ARMs supervised by ESMA or the FCA about joining.
ARMs versus trade repositories – the advocacy positioning
The substantive case TARMA expects to make centres on a structural distinction between ARMs and the trade repositories operating under EMIR and SFTR. Trade repositories are mandatory; ARMs are not. Investment firms can report transaction data directly to NCAs and bypass the ARM channel entirely.
A meaningful proportion of investment firms already do. According to ESMA’s 2024 Report on Quality and Use of Data, transactions submitted through an ARM accounted for 52.28% of MiFIR transaction reports in 2024, down from 54.59% in 2023 – with two of the five licensed ARMs accounting for over 90% of those submissions. Just under half of all MiFIR transaction reports are filed directly to NCAs, and the ARM share has edged downwards rather than upwards. The simplification agenda’s shift of regulatory weight onto Article 26 data does not, in itself, guarantee that the ARM channel grows.
That makes TARMA’s positioning question sharper than the press release framing implies. “Regulators and supervisors are actively working toward simplification and convergence across reporting regimes,” Navarro says. Convergence across regimes – rather than wholesale consolidation into a single mechanism – is the direction of travel he describes, and one in which ARM-specific interests need to be articulated as part of a broader cross-regime conversation.
A second element of TARMA’s positioning concerns competition from technology providers offering ARM-like services without the regulated ARM designation, and therefore without the same RTS 22 oversight obligations or data quality accountability. Navarro frames this as a market integrity issue rather than a commercial complaint – though the line between the two is unlikely to stay clean as supervisory expectations on ARM data quality intensify.
The hardening perimeter
The simplification agenda is reducing the number of reports investment firms must file. But it is concentrating regulatory weight onto the data channels that remain – and ARM data is now one of those channels. TARMA’s launch is the visible signal that the ARM regulatory perimeter is hardening, both in supervisory expectations on data accuracy and in the boundary between regulated ARMs and unregulated providers. How far the convergence Navarro describes goes – whether it stays at the level of cross-regime alignment or evolves into something more structural – will shape whether TARMA proves a permanent fixture or an interim body for a transitional period.
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