The move from T+2 to T+1 represents a major transformation for the European financial industry, impacting every stage of the settlement value chain, including asset managers, brokers, custodians and financial market infrastructures. Each participant’s readiness for this transition depends not only on internal preparation, but also on the collective preparedness of the market as a whole. Compliance with T+1 must therefore be approached both individually and as part of the broader settlement chain to ensure a smooth and coordinated transition.
As 2026 marks the implementation of T+1, the focus is now shifting decisively towards testing and operational readiness, with the aim of being fully prepared for the market‑wide testing phase planned for 2027.
Publication of the EU, UK and Switzerland T+1 testing plan
At a launch event held on 25 March in London, the EU T+1 Industry Committee unveiled the joint testing plan for the EU, the UK and Switzerland. The report, published by a dedicated testing task force with input from market participants across the entire settlement value chain, sets out a collective framework to support industry‑wide preparation for the transition to T+1.
Euronext is proud to have contributed to this work through the co‑leadership of a T+1 testing sub‑group and active participation in industry events, helping to translate the outcomes into practical guidance for testing preparation.
The plan covers logistical and scheduling aspects, including:
- The testing timeline, which starts now and sets out the testing windows planned for 2027, during which all major financial market infrastructures and testing providers are expected to make their environments available;
- The testing scenarios to be considered, ensuring that testing plans are aligned with each stakeholder’s specific requirements;
- The assessment to de-risk the transition, reflecting that readiness extends beyond testing activities alone and requires firms to conduct a gap analysis of the four key metrics (allocations & confirmations, timing of settlement instructions, CSD matching rates, and settlement rates) to enhance processes ahead of go‑live.
The Industry Committee highlights the following three key messages to take away from its testing approach and recommendations:
- Automation is a key success factor: With participants having only 20% of the current processing time to complete the same volume of tasks, automation is essential to maintain efficiency.
- Your readiness is dependent upon the readiness of the settlement chain of which you are a part: T+1 is a collective effort, and each participant’s preparedness relies on the entire value chain being ready. If any link is unprepared, the whole process may be compromised.
- Start testing now: Beginning T+1 preparations in 2027 would be too late, as the transition requires extensive testing of internal systems and processes well in advance of market‑wide testing. As highlighted by Euronext’s own Paolo Carabelli, co-lead of the EU T+1 Industry Committee’s Testing Task Force in Frankfurt on 21 April :
Testing helps firms understand where action is required and where processes need to accelerate. Starting now is critical to identify internal issues, but also to test interoperability with partners across the settlement chain. Testing helps you move towards T+1 progressively, because in the end T+1 is not a sprint but a stage race.
Euronext’s preparation for T+1 testing
Euronext is currently defining its testing approach in accordance with the Industry Committee’s plan and the detailed schedule below. This schedule outlines the period for upscaling internal processes and mapping test scenarios. It also details the market-wide testing windows in 2027 and the implementation timeline for the new operational day, including the new settlement optimisation gating event.
Source: European Union (EU), United Kingdom (UK), and Switzerland (CH) T+1 Testing Plan
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In blue: General Industry Testing Period
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In green: Dedicated period to support testing of the new Operational Day and the Settlement Optimisation Gating event
In this context, Euronext is completing a mapping of all end-to-end testing scenarios to ensure a fully comprehensive testing approach. Close coordination will also be carried out with various market participants and FMIs, both internally and externally, to ensure successful end-to-end testing.
Next steps for T+1 testing
Euronext strongly encourages all market participants to begin their preparations and testing activities now. Proactive and coordinated testing will be fundamental to ensuring a smooth and successful transition for all market participants. Firms should assess both their internal processes and external interactions, as T+1 readiness cannot be achieved in isolation - cooperation across the market is key.
In addition, Euronext is committed to providing clients with all the necessary information to support successful T+1 testing and will share a high-level testing strategy in the coming months to help secure coordination and alignment ahead of joint testing.
Your usual project team contacts remain available should you require any additional information regarding testing activities.
Additional source
T+1 readiness in Europe and the UK: a call for action in 2026 - Event recorded on 25 March