A typical UK lower-mid-market deal moves from signed LOI to exchange in 4-6 weeks. The critical path tends to be tax-deed scope and regulatory clearance, not the data-room itself. NSI, FCA and CMA clocks can extend completion materially.
Direct answer
A UK lower-mid-market diligence timeline runs 4-6 weeks from LOI to exchange. FCA change-of-control adds a 60 working-day decision clock. NSI Act mandatory notification adds a 30 working-day acceptance period before the call-in window. CMA Phase 1 review takes 40 working days from notification. Plan completion 0-30 days after exchange.
Week 0
LOI / heads of terms signed
- - LOI / heads signed.
- - Exclusivity window agreed.
- - Adviser engagements scoped, data room access provisioned.
Week 1
Open data room, first-pass
- - FDD partner reads management accounts.
- - Legal partner reads CA / PSC / register pack.
- - Tax partner reads CT computations.
- - First Q&A list issued.
Week 2
Deep-dive workstreams
- - Q&A turn from seller.
- - FDD QoE adjustments drafted.
- - Commercial DD interviews booked.
- - IT / cyber report kicked off.
- - Phase I ESA commissioned if relevant.
Week 3
Findings consolidate
- - Draft FDD report circulated.
- - Tax-deed scope drafted.
- - Customer reference calls.
- - Regulatory check (NSI, CMA, FCA) confirmed.
Week 4
Reports finalised
- - Final FDD, tax DD and legal DD reports.
- - Disclosure letter first draft.
- - W&I underwriter market sounded if relevant.
Week 5-6
Negotiation and exchange
- - SPA negotiated.
- - Disclosure letter agreed.
- - Conditions precedent signed off.
- - Exchange.
- - Completion typically 0-30 days after exchange.
Where the timeline slips
- NSI Act mandatory notification. 30 working-day acceptance period before a call-in window; 30 working-day review can extend by 45.
- FCA change-of-control. 60 working-day determination period from a complete application.
- CMA Phase 1. 40 working days; Phase 2 adds 24 weeks if the deal is referred.
- Pension scheme clearance. 3 months from a TPR clearance application if a DB scheme is in scope.
- Tax-deed negotiation. Often the longest single negotiation strand; budget two weeks of partner time.
This page is anchored to UK primary legislation and named regulator guidance only. Not legal advice. Confirm position with your appointed adviser before signing.