MiFIR Transaction Reporting Explained: Fields, Filing and Errors

Updated September 2026

What Is MiFIR Transaction Reporting? Article 26 in Plain Terms

MiFIR transaction reporting is the obligation, set out in Article 26 of Regulation (EU) No 600/2014 (MiFIR), that applies to investment firms and, under Article 1(2), to credit institutions when they provide investment services and/or perform investment activities. Where such an entity executes a reportable transaction, complete and accurate details must be reported to the competent authority. Article 26(1) fixes the deadline: reports go to the competent authority as quickly as possible, and no later than the close of the following working day. That next-working-day timing is what practitioners call T+1.

The Article 26 obligation applies to in-scope investment firms and credit institutions that execute transactions in reportable instruments. Second, under Article 26(5), the operator of a trading venue reports the details of transactions in instruments traded on its platform that are executed through its systems by a firm which is not itself subject to MiFIR. A transaction here means, broadly, the acquisition or disposal of a reportable financial instrument, with the precise meaning and the carve-outs set out in Commission Delegated Regulation (EU) 2017/590, the regulatory technical standard known as RTS 22.

This guide relies on the consolidated text of MiFIR as amended by the MiFIR Review (Regulation (EU) 2024/791), together with RTS 22 (Commission Delegated Regulation (EU) 2017/590) as it currently stands. Where the MiFIR Review has changed the Level 1 text but the implementing detail has not yet followed, the guide says so rather than presenting a future state as settled. For the closely related derivatives regime that often runs in parallel, see our companion explainer on EMIR reporting.

MiFID II Transaction Reporting vs MiFIR Transaction Reporting: One Regime, Two Names

Searchers reach this topic under two labels, and both point to the same regime. The reporting obligation itself sits in MiFIR, specifically Article 26. MiFID II, Directive 2014/65/EU, is the wider legislative framework that the obligation serves: it defines investment firms, financial instruments and trading venues, and it sets the conduct and market-integrity objectives that transaction data supports. Because the reporting sits inside the combined MiFID II and MiFIR package, the market often says “MiFID II transaction reporting” and “MiFIR transaction reporting” to mean the same thing.

The field-level interpretation comes from ESMA. Its Guidelines on transaction reporting, order record keeping and clock synchronisation, and the associated questions-and-answers, explain how to populate individual fields in scenarios the legal text does not spell out. So the layering is straightforward: MiFIR Article 26 for the obligation, RTS 22 for the fields and formats, and ESMA guidelines for the practical interpretation. A reader who standardised on either name is in the right place.

Which Instruments Fall in Scope: The Article 26(2) Test

Article 26(2) sets the scope test. Under ESMA’s current transitional position, the Article 26 text in the MiFIR consolidation of 9 January 2024 remains applicable until revised RTS 22 starts applying. The current reporting obligation applies to:

financial instruments admitted to trading or traded on a trading venue, or for which a request for admission to trading has been made, irrespective of whether the individual transaction is carried out on the venue;
financial instruments where the underlying is a financial instrument traded on a trading venue;
financial instruments where the underlying is an index or a basket composed of financial instruments traded on a trading venue.

Regulation (EU) 2024/791 amends Article 26(2) to add a reporting limb for OTC derivatives referred to in Article 8a(2). ESMA states that those Article 26 amendments will apply only when revised RTS 22 starts applying. Until then, the Article 26 text in the 9 January 2024 consolidation and current RTS 22 remain applicable.

Deciding whether a given instrument meets the test is largely a reference-data exercise. Whether an instrument is “traded on a trading venue” is established from the identifying reference data that venues submit to competent authorities under MiFIR Article 27, which ESMA consolidates in its Financial Instruments Reference Data System (FIRDS). Firms use FIRDS to check reportability and to source the instrument reference data a report needs. Where the classification of a crypto-asset is uncertain, the assessment must be made against the applicable MiFID II financial-instrument criteria, taking account of ESMA’s Guidelines on the conditions and criteria for qualification of crypto-assets as financial instruments and the relevant competent-authority position; see our note on ESMA’s crypto-asset financial-instrument classification.

What a Transaction Report Contains: RTS 22 Annex I by Field Group

RTS 22 Annex I (Table 2) sets out the reportable fields. Rather than reading them as a flat list, it helps to group them by what each identifies:

Buyer and seller identification, including the national identifier rules for natural persons and the legal entity identifier for legal persons;
Instrument identification, using Field 41 and, where applicable under RTS 22, the instrument-detail fields 42 to 56;
Price and quantity, with notional amount and currency where relevant;
Venue, using the market identifier code or the code for off-venue execution;
Short-selling and waiver indicators, alongside the commodity-derivative and securities-financing flags; and
Investment-decision and execution identifiers, naming the person or algorithm responsible within the firm.

The field-by-field detail, including how conditional fields behave, is in the data-elements section below. On the question practitioners ask most, has RTS 22 been rewritten under the MiFIR Review, the current answer is no. ESMA consulted on revising RTS 22 (Article 26) and RTS 24 (Article 25) in October 2024. In its June 2025 Final Report on those standards, it decided not to propose substantive amendments at that stage, and instead opened a call for evidence on a more holistic transaction-reporting framework spanning MiFIR, EMIR and SFTR. On 2 July 2026 ESMA published its Final Report on transaction-reporting simplification, setting out a ‘Report Once’ approach and recommendations for further legislative and implementation work. Until any revised standard is adopted and applies, RTS 22 as it stands (Commission Delegated Regulation (EU) 2017/590) governs the fields. We follow that workstream in our coverage of ESMA’s transaction reporting simplification.

How a Report Reaches the Competent Authority: Three Routes and the LEI Rule

Article 26(7) sets out three ways a transaction report can reach the competent authority. The report may be made:

by the investment firm itself, using the submission arrangements specified by its competent authority;
by an approved reporting mechanism (ARM) acting on the firm’s behalf; or
by the trading venue through whose system the transaction was completed.

The investment firm remains responsible for completeness, accuracy and timely submission, but Article 26(7) contains a derogation: where failures are attributable to an ARM or trading venue submitting on the firm’s behalf, the firm is not responsible for those failures and the ARM or venue is responsible. The firm must nevertheless take reasonable steps to verify completeness, accuracy and timeliness.

One prerequisite sits in front of all three routes. Article 26(6) requires firms to use a legal entity identifier (LEI) to identify clients that are legal persons, and the same LEI discipline applies to the reporting firm and its legal-entity counterparties. A legal-entity client must be identified by LEI under Article 26(6), and RTS 22 prevents an investment firm from providing a service that triggers transaction reporting on behalf of an LEI-eligible client before obtaining that client’s LEI. LEIs are issued and renewed through the Global Legal Entity Identifier system and validated against the GLEIF register.

Why MiFIR Transaction Reporting Matters

The obligation is one of the most data-intensive in European financial regulation. Investment firms executing reportable transactions, and trading venues in the cases specified by Article 26(5) or when submitting under Article 26(7), submit transaction data to competent authorities. A systematic internaliser is not a separate Article 26 reporting category from an investment firm. The volumes are large, the fields are prescriptive, and the reference data behind them changes constantly.

MiFIR transaction reporting exists for one core reason: to give regulators a complete, accurate picture of who traded what, when, and at what price. That visibility is how NCAs detect market abuse, monitor systemic risk, and enforce conduct rules. Article 26 transaction reports support supervisory market monitoring, including market-abuse detection and other analytical uses.

For reporting entities, the obligation is enforced. Miss a deadline, submit incomplete data, or fail to identify your counterparty correctly, and you face regulatory findings, fines, or enforcement action.

Legal Basis and Scope

MiFIR Article 26 and RTS 22

The core legal requirement lives in MiFIR Article 26 (Regulation (EU) No 600/2014, as amended by Regulation (EU) 2024/791). It requires investment firms executing transactions in financial instruments to report details to their NCA.

The technical detail is in Commission Delegated Regulation (EU) 2017/590, commonly known as RTS 22. RTS 22 defines:

The 65 fields in Annex I Table 2, with each field populated in accordance with its stated applicability conditions
Timing and format requirements
What constitutes a transaction and execution, and the operational rules for order transmission
How to handle corrections and cancellations

Clock synchronisation is now governed by Commission Delegated Regulation (EU) 2025/1155. It repealed Commission Delegated Regulation (EU) 2017/574 with effect from 2 March 2026, and references to the repealed Regulation are to be construed as references to Regulation (EU) 2025/1155.

Important: The MiFIR review (Regulation (EU) 2024/791) entered into force on 28 March 2024 and introduces changes to Article 26, including revised scope for OTC derivatives reporting. ESMA states that the Article 26 amendments will apply when revised RTS 22 starts applying; until that application date, the Article 26 text in the 9 January 2024 MiFIR consolidation and current RTS 22 apply. ESMA consulted on revising RTS 22 in October 2024 but, in its June 2025 Final Report, decided not to propose substantive amendments at that stage, so the existing RTS 22 continues to apply. Monitor ESMA publications for the status of the transaction reporting review.

RTS 22 Annex I states that all Table 2 fields are mandatory unless stated otherwise; individual field descriptions then specify their applicability conditions.

Reportable Instruments Under Article 26

MiFIR Article 26(2) defines which instruments are in scope. Under the currently applicable Article 26(2), reporting applies to financial instruments admitted to trading or traded on a trading venue or for which a request for admission to trading has been made; financial instruments whose underlying is a financial instrument traded on a trading venue; and financial instruments whose underlying is an index or basket composed of financial instruments traded on a trading venue.

Equities: Shares and depositary receipts admitted to or traded on a trading venue, or for which a request for admission has been made. ETFs listed on a trading venue are also reportable.

Debt instruments: Bonds admitted to trading on a trading venue. Government bonds, corporate bonds, structured bonds, and other securitised debt are in scope if TOTV.

Derivatives: under the currently applicable Article 26(2), a derivative is reportable if it is itself admitted to trading, traded on a trading venue or subject to a request for admission, or if its underlying is a financial instrument traded on a trading venue, or its underlying is an index or basket composed of financial instruments traded on a trading venue. Reportability should not be inferred merely from the derivative’s asset-class label.

Commodity derivatives: a commodity derivative is reportable where it meets the currently applicable Article 26(2) scope test, including where the derivative itself is admitted to trading, traded on a trading venue or subject to a request for admission. An OTC commodity derivative is not made reportable merely because its commodity underlying is traded on a venue: Article 26(2)(b) requires the underlying to be a financial instrument traded on a trading venue.

Emission allowances and derivatives on emission allowances are reportable where the relevant instrument meets the currently applicable Article 26(2) scope test.

What’s changing under the MiFIR review: Regulation (EU) 2024/791 amends Article 26(2) to include defined OTC derivatives referred to in Article 8a(2), but ESMA states that those Article 26 amendments will apply only when revised RTS 22 starts applying. Until then, the Article 26 text in the 9 January 2024 consolidation and current RTS 22 remain applicable.

Who Reports Under Article 26

Reporting Entities

MiFIR Article 26 imposes reporting obligations on:

1. Investment firms and credit institutions: MiFIR applies to investment firms authorised under MiFID II and to credit institutions authorised under Directive 2013/36/EU when providing investment services and/or performing investment activities. Where such an entity executes a transaction in a reportable instrument, Article 26 applies subject to the execution and transmission rules in RTS 22.

2. Trading venues: Under Article 26(5), a trading venue operator reports transactions executed through its systems by a member, participant or user that is not subject to MiFIR. Separately, Article 26(7) allows the trading venue through whose system a transaction was completed to submit a report on behalf of an investment firm. Article 26(5) is not the provision governing venue submission on behalf of a MiFIR investment firm.

3. Systematic internalisers: an SI is subject to Article 26 where, as an investment firm, it executes a transaction that meets the applicable transaction-reporting scope.

4. Branches of non-EU firms: A branch of a third-country firm established in the EU must report if it would be required to do so as an EU firm.

Who Reports What

The investment firm that executes the transaction is the reporting entity. For a broker executing a client order, the broker reports. When a trading venue reports on behalf of firms, the venue submits the report. For a transaction with an SI, SI status does not make the SI the sole reporter: each in-scope investment firm that executes the reportable transaction has its own Article 26(1) reporting obligation, subject to the RTS 22 execution and order-transmission rules.

Where an investment firm transmits an order, it is treated as having transmitted the order for RTS 22 purposes only if the conditions in Article 4 are met: the transmitting firm sends the prescribed order details to another investment firm, the receiving firm is subject to Article 26(1), and the receiving firm agrees either to report the transaction resulting from the order or to transmit the order details onward in accordance with Article 4.

What Gets Reported: The Data Elements

RTS 22 Annex I Table 2 specifies 65 transaction-reporting fields. Each field maps to a specific aspect of the trade.

Core Mandatory Fields

Transaction identifiers include the Transaction Reference Number (Field 2), the Trading Venue Transaction Identification Code where Field 3 applies, and the trading date and time in Field 28. For transactions executed on a trading venue, Field 28 follows the applicable business-clock rules; for transactions not executed on a trading venue, RTS 22 requires reporting at least to the nearest second. Commission Delegated Regulation (EU) 2017/574 was repealed from 2 March 2026 and replaced by Delegated Regulation (EU) 2025/1155. Current RTS 22 has no separate reporting-timestamp field.

Instrument identification: Field 41 uses the ISIN where that field applies. Fields 42 to 56 are subject to their own applicability conditions and are not applicable where the transaction is executed on a trading venue or with an investment firm acting as an SI, or where Field 41 contains an ISIN present in ESMA’s reference-data list.

Buyer and seller details: legal entities are identified by LEI; natural persons are identified using the national-client-identifier method in RTS 22 Article 6 and Annex II. A national identifier is not a substitute for a legal-entity client’s LEI: RTS 22 prevents an investment firm from providing a service that triggers transaction reporting on behalf of an LEI-eligible client before obtaining that client’s LEI.

Quantity and price: Field 30 reports quantity using the applicable units, derivative contracts, nominal value or monetary value; Fields 33 and 34 report price and price currency; Field 35 reports net amount only for debt instruments; and Field 38 captures an up-front payment where applicable.

Venue and execution: Field 36 uses the relevant MIC for execution on a trading venue, systematic internaliser or organised trading platform outside the Union. XOFF applies in the circumstances specified in Field 36 for instruments admitted to trading, traded on a trading venue or subject to a request for admission when execution is off the specified venues or platforms; XXXX applies in the specified underlying-traded-on-venue case for instruments that are not themselves admitted to trading, traded or subject to a request for admission.

Decision maker and executor: Field 57 identifies the person or algorithm responsible for an investment decision within the firm where that field applies; Field 59 identifies the person or algorithm responsible for execution. Natural-person identifiers follow RTS 22 Article 6 and Annex II, while algorithm identifiers follow the RTS 22 rules for persons and algorithms. Current CSSF transaction-reporting material does not establish a separate CSSF-assigned dealer-number identification method.

Flags and indicators: Short selling indicator, waiver indicator (for certain pre-trade transparency waivers), commodity derivative indicator, securities financing transaction indicator.

Decision and transmission data: investment-decision and transmission-of-order fields are populated in accordance with their individual RTS 22 applicability conditions.

Conditional Fields

Many fields are conditional, required only in specific scenarios:

ISIN alternatives: Where Field 41 is not applicable or is not populated, Fields 42 to 56 are populated only in accordance with each field’s individual applicability conditions in RTS 22 Table 2.
Counterparty LEI: Required if counterparty is a legal entity
Algorithm identifier: Where the applicable role is performed by an algorithm, identify the algorithm in Field 57 for an investment decision within the firm and in Field 59 for execution, in accordance with RTS 22 Articles 8 and 9.
Quantity: Field 30 uses the applicable quantity representation for the instrument; current RTS 22 does not contain a generic ‘notional amount’ field required for all derivatives and bonds.
Short selling indicator: populate Field 62 where its applicability conditions are met; use SESH or SSEX for a short sale, SELL for no short sale, or UNDI where permitted.
Up-front payment: Field 38 reports the monetary value of any up-front payment received or paid by the seller.

Reporting systems must handle conditional logic correctly. Omit a mandatory field and the report fails validation. Populate a field that should be blank and you may trigger queries.

Timing and Deadlines

Article 26(1) requires reporting as quickly as possible and no later than the close of the following working day. Firms must also follow the competent authority’s technical cut-off rules. For CSSF TAF reporting, the CSSF specifies a deadline of 23:59:59 UTC on the working day following execution.

RTS 22 Table 2 contains the transaction execution date and time in Field 28 but does not contain a separate reporting-timestamp field. Submission timeliness is assessed against the Article 26(1) reporting deadline.

Failure to report by deadline is a breach of Article 26. The Article 26 reporting deadline is binding; supervision and enforcement are carried out by the relevant competent authorities under the applicable legal framework.

Approved Reporting Mechanisms (ARMs)

An Approved Reporting Mechanism is a data reporting services provider that reports transaction details to competent authorities or ESMA on behalf of investment firms. ESMA’s direct authorisation and supervisory responsibilities for data reporting services providers date from 1 January 2022 under MiFIR as amended by Regulation (EU) 2019/2175, not the 2024 MiFIR Review; APAs and ARMs falling within the statutory derogation remain under the relevant national competent authority.

An ARM is authorised to report transaction details to competent authorities or ESMA on behalf of investment firms. Any additional connectivity, validation, audit-trail or correction-workflow services depend on the provider’s service offering.

When a firm reports via an ARM, the ARM submits the report on the firm’s behalf. Article 26(7) generally leaves the investment firm responsible for completeness, accuracy and timeliness, but provides that the firm is not responsible for failures attributable to the ARM; the firm must nevertheless take reasonable steps to verify the reports submitted on its behalf.

Firms using the direct reporting route must follow their NCA’s current technical submission arrangements. In Luxembourg, the CSSF’s TAF documentation specifies the accepted technical transmission arrangements.

MiFIR vs. EMIR: The Overlap

A derivative trade can trigger both MiFIR and EMIR reporting obligations. Understanding the distinction is important:

MiFIR reports to the NCA and covers transaction details (who traded, what, when, at what price). The purpose is market abuse detection and conduct supervision.
EMIR reports to a registered Trade Repository and covers derivative contract details, valuations, and collateral. The purpose is systemic risk monitoring and OTC derivatives transparency.

Example overlaps:

An equity option traded on a venue may be reportable under both regimes: under MiFIR, the executing in-scope firm has the Article 26 obligation unless Article 26(5) applies to a member, participant or user not subject to MiFIR, while a trading venue may submit on a firm’s behalf under Article 26(7); under EMIR, Article 9 reporting applies subject to the applicable reporting-responsibility rules and exemptions.
A Bund future on Eurex: where the MiFIR Article 26 scope test is met, the executing investment firm has the reporting obligation; a trading venue may submit under Article 26(7), and has the Article 26(5) reporting duty for a member, participant or user not subject to MiFIR. EMIR Article 9 reporting of a derivative contract does not depend on whether the contract is cleared, subject to the applicable reporting-responsibility rules and exemptions.
An FX spot trade: Not MiFIR reportable (FX spot is not a financial instrument under MiFID II). Not EMIR reportable (FX spot is not a derivative).
An OTC interest rate swap between two banks: under the currently applicable Article 26(2), MiFIR reportability must be assessed against the three operative scope limbs; an interest-rate underlying is not itself a financial instrument traded on a trading venue. The future Article 8a(2) transaction-reporting limb is not yet operative. EMIR Article 9 must be assessed under its own reporting-responsibility and exemption rules.

Where a transaction is reportable under both MiFIR and EMIR, the reporting streams are separate and the data elements and recipients differ; MiFIR Article 26(1) and EMIR Article 9(1) both generally require reporting no later than the following working day, subject to their respective regime-specific rules. Securities financing transactions are generally excluded from the RTS 22 definition of a transaction for MiFIR Article 26 purposes under RTS 22 Article 2(5)(a), subject to the stated ESCB-counterparty exception, and are reported under SFTR where SFTR applies; see our guide to SFTR reporting.

Reference Data Challenges

A key operational challenge in transaction reporting is reference data completeness and accuracy.

Client Identification

Every client must be identified. Legal entities use their LEI (20-character alphanumeric code, validated via the GLEIF database). Natural persons use national client identifiers, which vary by country and nationality:

The applicable natural-person identifier is selected by nationality under RTS 22 Article 6 and the country-specific priority table in Annex II. The firm uses the highest-priority Annex II identifier that the person has. There is no EU-wide passport → identity-card → tax-number hierarchy: the priorities differ by country. CONCAT is used only where Annex II specifies it, with multiple-nationality cases handled under Article 6.

A client onboarded years ago may lack an LEI. A client in multiple jurisdictions may have identifiers in several systems. Data quality management is an ongoing operational task.

Instrument Identification

Where RTS 22 Field 41 requires identification by ISIN, the correct ISIN must be reported; where Field 41 is not applicable, the instrument-detail fields apply as specified in Table 2. Where Field 41 is not applicable or is not populated, Fields 42 to 56 are populated according to their individual RTS 22 applicability conditions. They comprise instrument-detail fields such as CFI classification, notional currencies, underlying instrument information and derivative characteristics; they do not form a single generic ‘alternative identifier’ that must always be constructed in full.

Firms rely on reference data providers (Bloomberg, LSEG/Refinitiv, SIX, ANNA DSB) for instrument data. The ANNA DSB issues ISINs for OTC derivatives.

Natural Person Identification

A transaction report does not always identify a natural person for both roles. Field 57 applies to an investment decision within the firm and may identify a person or algorithm; Field 59 identifies the person or algorithm responsible for execution. Where a natural person is reported, Article 6 and Annex II determine the identifier by nationality, and CONCAT is used only where Annex II specifies it.

The CSSF applies RTS 22 Article 6 and Annex II to natural-person identifiers and specifically checks that CONCAT is used only where permitted by Annex II. Firms therefore need controls capable of producing the applicable identifiers for reportable persons.

The challenge: firms must maintain accurate person registries across systems.

Common Reporting Errors

NCAs including the CSSF publish transaction-reporting data-quality findings. Examples of issues identified through supervisory data-quality work include:

1. Missing or Invalid ISINs

Incorrect instrument identification or incorrect population of the instrument-detail fields can make a transaction report inaccurate or inconsistent with the applicability conditions in RTS 22 Table 2.

2. Incorrect Buyer/Seller LEI

Legal-entity clients must be identified by LEI. CSSF supervisory material has identified missing or invalid LEIs as a transaction-reporting issue, and reports containing LEIs that are not valid on the trade date may be rejected. A natural-person identifier is not an alternative to an LEI for a legal-entity client.

3. Missing Natural Person Identifiers

Decision maker or executor not identified or identified with wrong ID type or format. Especially problematic for firms reporting to multiple NCAs.

4. Timestamp Errors

Execution timestamp in wrong format (must be ISO 8601 / UTC), missing time zone designation, or insufficient granularity. Reporting timestamp confused with execution timestamp.

5. Short Selling Indicator Not Populated

RTS 22 Field 62 applies only where the instrument is covered by Regulation (EU) No 236/2012 and the seller is the investment firm or its client. The permitted codes are SESH for a short sale without exemption, SSEX for a short sale with exemption, SELL for no short sale and, where permitted after a best-efforts assessment, UNDI for information unavailable.

6. Conditional Fields Missing or Over-Populated

Incorrect quantity representation or missing instrument-detail fields where RTS 22 makes them applicable; use of an LEI where the buyer or seller is a natural person rather than the Article 6 identifier; or incorrect person/algorithm population in Fields 57 or 59. Systems must apply the individual Table 2 field conditions.

Your Own Completeness and Accuracy Controls

Catching these errors is not left to the regulator alone. RTS 22 Article 15 requires investment firms to have arrangements in place to ensure their transaction reports are complete and accurate. Those arrangements must include testing of the reporting process and regular reconciliation of front-office trading records against the data samples that competent authorities provide for that purpose. Where an authority does not provide samples, Article 15(4) requires the firm to reconcile its front-office records against the reports it has submitted, or that an ARM or trading venue submitted on its behalf, checking timeliness, the accuracy and completeness of each field, and compliance with the formats in Table 2 of Annex I.

Two further duties sit alongside reconciliation. Under Article 15(2), where a firm or venue becomes aware of an error or omission, a missing report, or a report made where no obligation existed, it must promptly notify the competent authority. Under Article 15(5), the reports viewed collectively must reflect all changes in the firm’s and its clients’ positions at the time transactions are executed. Competent authorities run their own data-quality feedback loops on top of this, returning validation feedback on rejected reports and publishing periodic data-quality reports.

MiFIR Transaction Reporting in Luxembourg

CSSF Requirements

Luxembourg, as a major financial centre, has significant MiFIR reporting volumes. The CSSF is the NCA.

Key Luxembourg specifics:

Natural person identification: The CSSF applies RTS 22 Article 6 and Annex II. CONCAT is used only for nationalities for which Annex II permits or requires it. Current CSSF transaction-reporting material does not establish a separate dealer-registration requirement.
Reporting channels: A firm may report on its own behalf or via an ARM, but under the current CSSF TAF Handbook its TAF files are not submitted directly to the CSSF; reporting entities must use an official transmission channel operator accepted by the CSSF.
Deadlines: For CSSF TAF reporting, no later than 23:59:59 UTC on the working day following execution (T+1).
Scope: The CSSF applies the EU MiFIR transaction-reporting framework and publishes Luxembourg transaction-reporting instructions and data-quality material through its Transaction Reporting page.

Cross-Border Reporting

A Luxembourg investment firm’s transaction-reporting competent authority is determined by the MiFIR branch and competent-authority rules, not by the Member State in which its client is located. Investment firms report transactions executed wholly or partly through a branch in accordance with Article 26 and the RTS 22 branch rules; a branch of a third-country firm reports to the competent authority that authorised the branch. Transaction data are subsequently exchanged between competent authorities under the applicable MiFIR arrangements.

Recent and Upcoming Changes

The MiFIR Review (Regulation (EU) 2024/791)

The MiFIR review entered into force on 28 March 2024. Key changes affecting transaction reporting include:

Revised OTC derivatives scope: Regulation (EU) 2024/791 amends Article 26(2) to include defined OTC derivatives referred to in Article 8a(2), but ESMA states that those Article 26 amendments will apply only when revised RTS 22 starts applying. Until then, the Article 26 text in the 9 January 2024 consolidation and current RTS 22 remain applicable.
ESMA supervisory role over ARMs: since 1 January 2022, under MiFIR as amended by Regulation (EU) 2019/2175, ESMA has direct responsibilities for data reporting services providers except APAs and ARMs falling within the statutory derogation, which remain under the relevant NCA.
Potential extension to AIFMs and UCITS managers: The European Commission was mandated to assess extending Article 26 reporting to AIFMs and UCITS management companies.
Revised RTS 22: ESMA consulted on revisions to RTS 22 in October 2024. In its June 2025 Final Report on RTS 22 and RTS 24, ESMA decided not to propose substantive amendments at that stage and opened a call for evidence on a more holistic transaction-reporting framework across MiFIR, EMIR and SFTR. The existing RTS 22 continues to apply until any revised standard is adopted and starts to apply.

ESMA states that the Article 26 amendments will apply when revised RTS 22 starts applying. Until that application date, the Article 26 text in the 9 January 2024 consolidation and current RTS 22 remain applicable.

Coming Soon: Template-by-Template Deep Dives

We’re building detailed, template-level guides for each reporting framework covered on RegReportingDesk. Whether you need a field-by-field walkthrough of specific reporting scenarios, data element mappings, or best practices, these guides are on the way. Bookmark this page and check back soon.

Frequently Asked Questions

What is MiFIR Article 26 transaction reporting?

Article 26 requires investment firms executing transactions in reportable financial instruments to report transaction details to their NCA within T+1. RTS 22 Annex I Table 2 contains 65 fields covering instrument identification, buyer/seller details, quantity, price and decision-maker information, with each field subject to its stated applicability conditions. Regulators use this data to detect market abuse and monitor markets.

Is MiFID II transaction reporting the same as MiFIR transaction reporting?

They name the same regime. The obligation sits in MiFIR Article 26; MiFID II (Directive 2014/65/EU) is the framework it serves, defining firms, instruments and venues. ESMA guidelines supply the field-level interpretation. The market uses both names interchangeably.

Which instruments are reportable?

Under the currently applicable Article 26(2), reportable instruments include equities, bonds, derivatives on reportable underlyings, commodity derivatives meeting the scope test, CFDs on reportable assets, and emission allowances where the relevant instrument meets the scope test. Under the currently applicable Article 26(2), the test covers instruments admitted to trading or traded on a trading venue or for which a request for admission has been made; instruments whose underlying is a financial instrument traded on a trading venue; and instruments whose underlying is an index or basket composed of financial instruments traded on a trading venue. Regulation (EU) 2024/791 adds a defined set of OTC derivatives referred to in Article 8a(2), but ESMA states those amendments apply only when revised RTS 22 starts applying.

What is the transaction reporting deadline?

Article 26(1) requires the report as quickly as possible and no later than the close of the following working day (T+1). For CSSF TAF reporting, the CSSF specifies a deadline of 23:59:59 UTC on the working day following execution.

What is an ARM?

An Approved Reporting Mechanism is a data reporting services provider that reports transaction details to competent authorities or ESMA on behalf of investment firms. It is one of three routes in Article 26(7), alongside direct submission by the firm and submission by the trading venue. ESMA’s direct supervisory responsibilities for ARMs date from 1 January 2022 under MiFIR as amended by Regulation (EU) 2019/2175, subject to the derogation for certain ARMs that remain under NCA supervision. The investment firm remains responsible subject to Article 26(7): it is not responsible for failures in completeness, accuracy or timeliness attributable to the ARM or trading venue, but must take reasonable steps to verify reports submitted on its behalf.

What is RTS 22?

Commission Delegated Regulation (EU) 2017/590, commonly known as RTS 22, specifies the detailed data fields, formats, and rules for transaction reporting under Article 26. Clock synchronisation is now governed by Commission Delegated Regulation (EU) 2025/1155, which repealed Delegated Regulation (EU) 2017/574 with effect from 2 March 2026. ESMA reviewed RTS 22 but, in its June 2025 Final Report, did not propose substantive amendments at that stage.

How does MiFIR relate to EMIR reporting?

Derivatives can trigger both MiFIR (to NCA) and EMIR (to trade repository) reporting. MiFIR covers transaction details for market abuse detection. EMIR covers derivative contract, valuation, and collateral data for systemic risk monitoring. Firms maintain parallel streams.

What are the most common errors?

Missing ISINs, incorrect buyer/seller LEI, missing natural person identifiers, timestamp format errors, and unpopulated short selling or conditional fields. Reference data quality and systematic validation are critical.

EMIR Reporting Explained: a guide to the derivative trade reporting obligation under EMIR, including counterparties, fields, and trade repository submission.
SFTR Reporting Explained: the securities financing transaction reporting framework under SFTR, which runs alongside MiFIR and EMIR for repos, securities lending, and margin loans.
ESMA Transaction Reporting Simplification: EMIR, MiFIR and SFTR: ESMA’s active workstream to reduce duplicative data across the three transaction reporting regimes, including the call for evidence and proposed single framework.
UK MiFIR Transaction Reporting Reform: the FCA’s post-Brexit reform of the UK transaction reporting regime under PS26/15, covering scope changes and the revised field set.
CSSF MiFID II and MiFIR FAQ Updates: Luxembourg-specific clarifications from the CSSF on transaction reporting scenarios including intra-group trades and natural person identification.

Key Takeaways

Article 26 requires investment firms to report transaction details to their NCA within T+1. The 65 data fields are specified in RTS 22 (Commission Delegated Regulation (EU) 2017/590).
“MiFID II” and “MiFIR” transaction reporting name the same regime. The obligation is in MiFIR Article 26; MiFID II is the framework; ESMA guidelines interpret the fields.
Reportable instruments are determined by the currently applicable Article 26(2) test, checked against ESMA reference data (FIRDS). Regulation (EU) 2024/791 adds a set of OTC derivatives referred to in Article 8a(2), but ESMA states those amendments apply only when revised RTS 22 starts applying.
Reports reach the competent authority by one of three routes under Article 26(7): the firm, an ARM, or the trading venue. An LEI is required to identify legal-entity clients under Article 26(6).
ESMA’s June 2025 Final Report proposed no changes to the existing RTS 22. On 2 July 2026 ESMA published its Final Report on transaction-reporting simplification; that work does not itself replace current RTS 22.
MiFIR and EMIR overlap for derivatives. A single derivative trade may trigger both MiFIR reporting (to NCA) and EMIR reporting (to trade repository). The data elements, recipients, and purposes differ.
Firms run their own controls under RTS 22 Article 15: testing, reconciliation against competent-authority data samples, and prompt notification of errors or omissions.

Sources and References

Regulation (EU) No 600/2014 (MiFIR), Markets in Financial Instruments Regulation; Article 26 establishes transaction reporting obligations. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32014R0600
Regulation (EU) 2024/791, MiFIR review amending Regulation (EU) No 600/2014 (entered into force 28 March 2024). https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32024R0791
Directive 2014/65/EU (MiFID II), Markets in Financial Instruments Directive, the framework the reporting obligation serves. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32014L0065
Commission Delegated Regulation (EU) 2017/590 (RTS 22), Regulatory technical standards on reporting of transactions to competent authorities; see Article 15 on methods and arrangements, Annex I for fields. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32017R0590
Commission Delegated Regulation (EU) 2025/1155, Clock synchronisation requirements; repealed Delegated Regulation (EU) 2017/574 with effect from 2 March 2026. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32025R1155
ESMA Final Report on RTS 22 (transaction data reporting) and RTS 24 (order book data), June 2025; ESMA proposed no substantive amendments to the existing standards at that stage. https://www.esma.europa.eu/document/final-report-rts-22-transaction-data-reporting-and-rts-24-order-book-data
ESMA Final Report on the Call for Evidence on a comprehensive approach for the simplification of financial transaction reporting (ESMA12-1406959660-3235), 2 July 2026; sets out a ‘Report Once’ approach and recommendations for further legislative and implementation work. https://www.esma.europa.eu/document/final-report-call-evidence-comprehensive-approach-simplification-financial-transaction
ESMA Guidelines on Transaction Reporting (ESMA/2016/1452), Detailed practical guidance on transaction reporting fields and scenarios. https://www.esma.europa.eu/document/guidelines-transaction-reporting-order-record-keeping-and-clock-synchronisation-under-mifid
ESMA MiFIR Review page, Implementation status, consultations, and guidance on the MiFIR review. https://www.esma.europa.eu/trading/mifid-ii-and-mifir-review
ESMA MiFIR Reporting page, TREM specifications, XML schemas, and reporting guidance. https://www.esma.europa.eu/data-reporting/mifir-reporting
ESMA FIRDS (Financial Instruments Reference Data System), Reference database for determining reportable instruments. https://www.esma.europa.eu/data-systematic-internaliser-calculations/firds-database
ANNA DSB (Derivatives Service Bureau), Global ISIN allocation for OTC derivatives. https://www.anna-dsb.com/
CSSF, Transaction reporting, Luxembourg transaction-reporting framework, reporting routes and current documentation: https://www.cssf.lu/en/transaction-reporting/
CSSF, TAF Handbook, version 2019.2, technical transaction-reporting arrangements, including the T+1 submission deadline: https://www.cssf.lu/en/Document/taf-handbook/
CSSF, Monitoring the quality of transaction reports received under Article 26 of MiFIR, 21 January 2026, current Luxembourg scope and data-quality findings: https://www.cssf.lu/en/2026/01/monitoring-the-quality-of-transaction-reports-received-under-article-26-of-mifir-4/

MiFIR transaction reporting currently remains governed by the Article 26 text applicable under ESMA’s transition, namely the 9 January 2024 MiFIR consolidation, together with current RTS 22 (Commission Delegated Regulation (EU) 2017/590). The Article 26 amendments made by Regulation (EU) 2024/791, including the Article 8a(2) OTC-derivatives limb, will apply when revised RTS 22 starts applying. ESMA’s June 2025 Final Report proposed no changes to current RTS 22; on 2 July 2026 ESMA published its Final Report on transaction-reporting simplification.

Disclaimer: The information on RegReportingDesk.com is for educational and informational purposes only. It does not constitute legal, regulatory, tax, or compliance advice. Always consult your compliance officer, legal counsel, or the relevant supervisory authority for guidance specific to your institution.

What Is MiFIR Transaction Reporting? Article 26 in Plain Terms

MiFID II Transaction Reporting vs MiFIR Transaction Reporting: One Regime, Two Names

Which Instruments Fall in Scope: The Article 26(2) Test

What a Transaction Report Contains: RTS 22 Annex I by Field Group

How a Report Reaches the Competent Authority: Three Routes and the LEI Rule

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