Regulatory Update | October 2026
In less than a year, the UK, EU and Switzerland will move to T+1 settlement together, with Liechtenstein following the Swiss model. On 11 October 2027, the time firms have to allocate, confirm, instruct and fund a trade will shrink to a single business day, cutting available post-trade processing time by around 80%.
For many firms, though, the more pressing date is much closer. From 7 December 2026, EU firms and their clients face their first binding obligations on allocations and confirmations, and in the UK, five of the Accelerated Settlement Taskforce’s critical actions fall due by the end of this year. Market-wide testing begins in February 2027.
2026 has been the year T+1 moved from plan to obligation. The EU rulebook is now final, the three jurisdictions have aligned their testing, and industry survey data gives a clearer picture of who is ready and who is not. In this update, we set out the key dates, what has changed this year, where readiness stands, and how firms can approach the year ahead.
T+1, T-1: one year to go
T+1 go-live is 11 October 2027 but the first binding obligation lands on 7 December 2026.
The EU rulebook is complete, the testing calendar published, and the readiness data now public.
Fixed calendar
| Date | Milestone | Detail |
| 7 Dec 2026 | EU allocation and confirmation obligations apply | Clients must deliver allocations and confirmations to the firm by 23:00 CET on trade date; firms confirm receipt within two hours, in machine-readable form. |
| 31 Dec 2026 | Five UK AST critical actions fall due | Five of the twelve critical UK Implementation Plan actions carry a 31 December 2026 completion date. |
| Feb 2027 | First coordinated market-wide testing window opens | Window 1 runs 1–12 February; five windows in all, closing 10 September 2027. |
| 1 Jul 2027 | EU amended CSD settlement-fails reporting applies | Revised reporting and publication requirements for CSDs take effect. |
| 11 Oct 2027 | T+1 go-live | UK, EU and Switzerland transition to T+1, Liechtenstein under the Swiss model. EU CSD requirements take effect. |
Uneven readiness industry-wide
Engagement has grown markedly over the past year: 83% of UK firms are now actively engaged in their T+1 programme, up from 66% in Q3 2025. That still leaves 17% not yet actively engaged in implementation, and dependencies across the chain remain a concern, with only 19% of firms saying their prime broker can support them today.
2026 changes
The EU rulebook finalised. ESMA confirmed the framework final in October 2026: the amended RTS is in the Official Journal, in force 3 November, with its main obligations and ESMA’s revised Guidelines applying from 7 December.
Three jurisdictions aligned their testing. The EU T+1 Industry Committee, the UK Taskforce and the Swiss Securities Post-Trade Council published a joint testing plan in March 2026, the first alignment of this scale.
Switzerland and Liechtenstein confirmed. Both move on 11 October 2027 alongside the UK and EU, closing the cross-border divergence risk that was open a year ago.
A public benchmark is coming. The Taskforce will set the post-go-live settlement-rate target from the average CREST rate for July to September 2027, publishing rolling three-month averages.
Sources: ESMA (October 2026); Commission Delegated Regulation (EU) 2026/1536, Official Journal of the EU; UK AST Implementation Plan, FAQ and 2026 readiness survey; joint EU, UK and CH T+1 Testing Plan (V2, September 2026); UK T+1 Pulse Survey (ValueExchange, Euroclear and DTCC, Q1 2026). Dates and requirements are subject to confirmation against the latest industry publications.
The run-up to go-live
The EU rules are final
The EU framework was completed this year: the amended RTS on Settlement Discipline is published in the Official Journal, in force from 3 November 2026, and ESMA’s revised Guidelines apply from 7 December. The UK’s legal instrument remains in draft and Switzerland proceeds on market recommendation, but all three, with Liechtenstein under the Swiss model, move on 11 October 2027, under a joint testing plan first published in March 2026.
At a glance: EU
| Figure | What it means |
| 23:00 CET | Allocation and confirmation cut-off, on trade date |
| 2 hours | To confirm receipt of an allocation |
| 23:59 CET | Settlement instruction to the SSS, on trade date where feasible |
| ~80% | Reduction in available post-trade processing time (UK AST FAQ) |
UK equivalents differ, and are market practice rather than regulation: allocation and confirmation by 23:59 UK time on trade date; CREST input by 21:00 UK time on trade date for UK-domiciled participants, with 05:59 UK time on T+1 intended for non-UK participants. Switzerland: matched by about 23:15 CET on trade date for the night-time cycle (CCPs 23:00).
First deadline: December 2026
From 7 December 2026, EU professional and retail clients must get allocations and confirmations to their investment firm by 23:00 CET on trade date, and firms must confirm receipt within two hours. Those messages must be electronic, standardised and machine-readable, with PSET, cash amount and participant identifiers added as required fields. In the UK, five of the Taskforce’s twelve critical Implementation Plan actions carry a 31 December 2026 completion date, and the first of five market-wide testing windows opens on 1 February 2027.
Conclusion
T+1 is a landmark modernisation of post-trade processes, and this year it became a dated obligation, binding in law in the EU, by market commitment in the UK and Switzerland.
Supervisory focus is now on examining evidence of readiness.
Firms that can show traceable requirements, tested connectivity and a defensible evidence pack will absorb October 2027 as a controlled event. Those that cannot will meet it as an incident.
A plan of approach
Below is an indication of what our approach would be to ensure success in executing on this transformation and meeting the regulatory deadline.
Our services are delivered by leading, expert practitioners in their field and every engagement will always be a bespoke design to meet your requirements.
| Step | Activity | Description | Indicative timing |
| 01 | Scope and regulatory baseline | Map the UK AST, ESMA and Swiss requirement sets line by line to legal entity, product and business line, classified as mandatory, critical or adopt-and-explain. | Now – Dec 2026 |
| 02 | Gap analysis across the trade lifecycle | Assess allocation, confirmation, SSI, settlement instruction, recall and funding flows end to end, and measure the gap between stated capability and actual processing times. | Now – Dec 2026 |
| 03 | Remediation, sequenced to the dates | Allocation and confirmation uplift, SSI remediation, automated stock-lending recalls, partial settlement and earlier FX execution, ordered so the dependencies land first. | Dec 2026 – Jun 2027 |
| 04 | Testing across the chain | Test strategy and acceptance criteria agreed before the first window opens, then bilateral and peer-to-peer testing through all five market-wide windows. | Feb – Sep 2027 |
| 05 | Evidence and traceability | Requirement-by-requirement traceability, named accountable owners and test results, held together as a readiness position that stands up to scrutiny. | Throughout |
| 06 | Go-live and stabilisation | Dress rehearsal, cutover, command centre and exception triage, with daily monitoring against the settlement-rate benchmark the Taskforce will publish. | From Oct 2027 |
Timing is indicative. Sequencing and duration depend on requirement scope, counterparty and custodian readiness, and participation in the market-wide testing windows.
