T+1 in the UK and EU: closing the 2027 readiness gap

On 11 October 2027 the UK, EU and Switzerland move to T+1 settlement together. Everything that happens after a trade — confirmation, allocation, currency funding, stock recalls — must finish in half the time it has today, and the date will not move.

The paper draws on the well-documented US transition of May 2024, where same-day affirmation rose from 73% of trades in January to roughly 95% at go-live. It shows why Europe's move is harder: more markets, systems and currencies, fail penalties already in force, and no larger T+2 market left to absorb the shock. The least appreciated constraint is currency funding — CLS is keeping its midnight cut-off, which makes T+1 a treasury problem before it is an operations one.

The full paper maps readiness function by function — affirmation, treasury, FX windows, lending recalls, exceptions, data quality — with the US evidence, a readiness heat-map and a sequence for the months before the 2027 dress rehearsals. Sources include ESMA, the UK Accelerated Settlement Taskforce, DTCC and AFME.