UK MARKETS REGULATION – Replacing the legacy UK MiFIR Article 25 / RTS 24 framework

Executive view

The FCA is moving order record-keeping into a new Handbook chapter, MAR 13. This replaces the requirements that sat under UK MiFIR Article 25 and RTS 24. The change is real, not cosmetic. Firms and trading venues will need to rethink how they capture, link and store order data, and how they can reconstruct an order’s full path when asked.

MAR 13 sits alongside revised rules for transaction reporting (MAR 14) and instrument reference data (MAR 15). The three chapters are related but distinct. Order records are not transaction reports, and neither is a substitute for the other.

The new rules are due to start on 3 April 2028. Until then, existing obligations continue. The practical task for firms is to map the differences now, test whether current systems can reconstruct an order lifecycle under the new model and keep an eye on the FCA’s remaining guidance.

FCA will consult on a new UK MiFIR Transaction Reporting User Pack in Q1 2027 and publish a final version of the User Pack by 3 April 2027.

Why the change matters

Order records exist so the regulator can rebuild what happened. That means seeing the original instruction, every amendment or cancellation, how the order was routed, what was executed, and which trades resulted. Incomplete or poorly linked data makes that reconstruction slow or impossible.

RTS 24 set out the technical detail for years. MAR 13 brings the equivalent UK requirements into the Handbook and updates them for the post-Brexit regime. The three new MAR chapters (13, 14 and 15) work together operationally, but each has its own purpose. Treating them as interchangeable is a common source of confusion in project planning.

What MAR 13 means in practice

A UK Handbook framework

Map your current order-record controls against MAR 13 and its annexes. Do not assume the old RTS 24 field list will survive unchanged. Policies, control inventories, business requirements and system documentation all need updating. Groups that operate in both the UK and the EU should identify where the two regimes diverge and where shared platforms need different logic.

Lifecycle completeness and linkage

The core test is whether you can reconstruct an order from start to finish and link it to the trades that followed. That includes new orders, amendments, cancellations, partial fills, full executions, rejections and routed orders. A single order ID is rarely enough. You need to preserve the relationships between order identifiers, event identifiers, timestamps, execution references and resulting transactions.

Data capture that actually works

MAR 13 is detailed. That makes source-data ownership and capture controls more important than ever. Check that you reliably capture client and submitting-party identifiers, decisionmaker or algorithm identifiers, order and execution references, sequencing information, and the required timestamps. Confirm the precise list against the final MAR 13 annex for your activity and system type.

Retention and retrieval

The five-year retention expectation remains. Retention alone is not the point. You also need to be able to pull a coherent, machine-readable history quickly, explain the lineage of the data, and show that later changes have not obscured the original order or its lifecycle.

Who is responsible for what

The rules apply to relevant investment firms and qualifying trading venues, but the exact obligations depend on the role you play. Distinguish the records you must create and keep from data you receive from venues, brokers or vendors. Outsourcing the technology does not remove accountability. You still need clear ownership, completeness checks, and evidence that you can produce the records when asked.

Implementation priorities

A practical readiness programme usually focuses on these areas:

Regulatory mapping: Map each MAR 13 requirement and annex field to the existing RTS 24 control, system field, data source and owner. Note the gaps and the assumptions.
Data dictionary and lineage: Build a controlled dictionary for each field: definition, format, permitted values, source system, transformation logic, null handling and validation rules.
Lifecycle and composite keys: Test how orders, amendments, cancellations, routes, rejections, partial fills and executions are linked. Do not rely on a single identifier where it cannot distinguish events.
Validation and reconciliation: Run both technical checks and business-rule checks. Reconcile order events to execution and transaction records. Investigate missing, duplicated, out-of-sequence or contradictory events.
Retention and retrieval: Test retention periods, access controls, historical reconstruction, machine-readable exports, and the ability to respond to regulatory requests within required timescales.
Governance and change control: Assign owners across trading, operations, compliance, data and technology. Version-control rule logic, document exceptions, and regression-test changes before they go live.

The relationship with MAR 14 and MAR 15

MAR 13 should be delivered as part of the wider market-data reform programme, but its requirements stay distinct. MAR 14 covers transaction reporting and MAR 15 covers instrument reference data. Shared identifiers, instrument classifications, timestamps and execution references create real dependencies. Inconsistent definitions or duplicated transformation logic will produce errors across multiple regulatory outputs.

PS26/15 sets out the new transaction-reporting framework, including a reduction from 65 to 52 fields and a shorter default back-reporting period. Those changes apply to transaction reporting, not directly to order record-keeping under MAR 13. CP26/34, published on 2 October 2026, consults on guidance, transitional provisions and consequential amendments. Monitor the consultation and the FCA’s technical materials. Do not treat draft schemas or proposed guidance as final.

The practical opportunity

The move from RTS 24 to MAR 13 is a chance to improve the quality and usability of order data rather than simply port existing fields into a new template. Firms that establish clear data ownership, robust lifecycle identifiers and transparent validation logic will find it easier to explain trading activity, investigate breaks and absorb future regulatory changes.

The useful test is reconstruction and evidence: can you show what was ordered, when it changed, where it was routed, how it was executed, and which transactions followed? A record that passes a technical schema check can still be incomplete or inconsistent with the actual order lifecycle. Controls need to test both format and meaning.

Conclusion

MAR 13 is the new UK Handbook framework for order record-keeping. It succeeds the legacy UK MiFIR Article 25 and RTS 24 requirements. Its significance is the expectation that firms maintain complete, connected and retrievable order-lifecycle records. With the start date set for 3 April 2028, the work of mapping requirements, testing data lineage and lifecycle reconstruction, and aligning with the related MAR 14 and MAR 15 reforms should already be underway. The aim is not simply to comply with a new chapter number. It is to produce order data that can be used for effective regulatory oversight.

We recommend that all records and associated data are retained using Write Once, Read Many (WORM) storage, or an equivalent immutable storage solution, to ensure that information is tamper-proof and cannot be altered, overwritten or deleted during the prescribed retention period. Furthermore, the storage environment should be logically and operationally independent of the firm’s core IT infrastructure, providing an additional layer of protection against unauthorised access, cyber threats, system failures or internal interference. This approach supports the integrity, authenticity and availability of retained records, strengthens the firm’s operational resilience and provides greater assurance that records remain complete, accurate and independently verifiable for regulatory, audit and evidential purposes.

Key regulatory references

Are Your Order Records Ready for MAR 13?

Moving from RTS 24 to MAR 13 takes more than updating a field list. Firms need to test whether they can reconstruct every order from instruction to execution, link each event to the resulting transactions, and retrieve that history quickly when the FCA asks. Gaps in data capture, lifecycle linkage or retention controls are far easier to fix now than after 3 April 2028.

Reg-X can help you get there. Our regulatory specialists work with investment firms and trading venues to map existing order-record controls against MAR 13, test lifecycle reconstruction and data lineage, and strengthen validation, reconciliation and recordkeeping controls across order records and transaction reporting.

Speak with our experts using the form below or email us at [email protected]. Tell us about your current order record-keeping setup and the challenges you’re facing, and we’ll show you where the gaps are and how to close them ahead of implementation.

FAQs on MAR 13

What is MAR 13?
MAR 13 is a new chapter in the FCA Handbook that sets out the UK’s order record-keeping requirements. It replaces the rules that previously sat under UK MiFIR Article 25 and RTS 24, and requires firms and trading venues to keep complete, linked and retrievable records of each order’s lifecycle.

When does MAR 13 come into force?
MAR 13 is due to apply from 3 April 2028. Until then, existing UK MiFIR Article 25 and RTS 24 obligations continue to apply.

Does MAR 13 replace RTS 24?
Yes. MAR 13 brings the UK equivalent of RTS 24 into the FCA Handbook and updates it for the post-Brexit regime. Firms should not assume the RTS 24 field list will carry over unchanged and should map their controls against the final MAR 13 annexes.

Who does MAR 13 apply to?
MAR 13 applies to relevant investment firms and qualifying trading venues. The exact obligations depend on the role a firm plays. Outsourcing technology to a vendor does not remove accountability for the records.

What is the difference between MAR 13, MAR 14 and MAR 15?
MAR 13 covers order record-keeping, MAR 14 covers transaction reporting and MAR 15 covers instrument reference data. They are related and share identifiers and timestamps, but each has its own purpose. Order records are not transaction reports, and one cannot substitute for the other.

How long must order records be kept under MAR 13?
The five-year retention expectation remains. Firms must also be able to retrieve a coherent, machine-readable order history quickly and show that later changes have not obscured the original order.

Does the reduction from 65 to 52 fields apply to MAR 13?
No. The reduction set out in PS26/15 applies to transaction reporting under MAR 14, not to order record-keeping under MAR 13.

What should firms do now to prepare for MAR 13?
Firms should map existing RTS 24 controls to MAR 13, test whether they can reconstruct a full order lifecycle, and review data lineage, validation and retention. They should also monitor CP26/34 and the FCA’s Transaction Reporting User Pack consultation, expected in Q1 2027.

« Technical Breakdown: Navigating FCA CP26/34 and the Post-MIFIR Reporting Era

MAR 13: The UK’s new order record-keeping framework