If a buyer has approached you about acquiring your business, you're probably wondering what happens next. This guide explains the due diligence and legal process you'll go through, the time commitment involved, and where professional support can make the biggest difference.

Most owner-managers have never sold a business before. The process is manageable, but it is intensive — and it runs on top of your day-to-day operations. Understanding what's coming helps you prepare properly and decide where you need support.

The Main Stages

Once a buyer is seriously interested, you will typically move through these five stages — often in sequence, sometimes with SPA negotiation running in parallel with due diligence.

1
Initial discussions and indicative offer
1–3 weeks
- The buyer will want to understand your business model, financials, and growth trajectory
- They will share an initial offer — often by email or in a short letter
- You will need to decode what they are actually proposing: enterprise value vs equity value, cash vs deferred consideration, conditions attached
2
Heads of Terms / Letter of Intent
1–2 weeks
- If both sides are interested, the buyer will propose formal terms
- This document sets out price, structure (cash / deferred / earn-out), key conditions, exclusivity period, and indicative timeline
- It is usually non-binding except for exclusivity and confidentiality
This is a critical negotiation point — the commercial terms agreed here typically stick. Take time to understand them fully before signing.
3
Due diligence
4–12 weeks, typically 6–8 weeks
- The buyer's team — financial, legal, tax, commercial, technical — will test everything
- You will be asked to populate a virtual data room with documents
- Expect multiple rounds of written questions and several management meetings
This is the most intense period for you personally — most sellers find it becomes almost a second job alongside running the business.
4
Sale and Purchase Agreement (SPA) negotiation
Runs in parallel with due diligence
- Your solicitor and the buyer's solicitor negotiate the main contract
- Key sections: price and payment mechanism, warranties, limitations on liability, restrictive covenants
- You will also prepare a disclosure letter — a formal disclosure against the warranties, cross-referenced to the data room
5
Completion
1–2 weeks after everything is agreed
- Final board and shareholder approvals
- Signing and exchanging documents
- Funds transfer and share transfer
- Companies House filings

What Due Diligence Actually Involves

Due diligence is when the buyer validates everything they care about. For a first-time seller, it can feel overwhelming — the volume and pace of requests is relentless, and it arrives while you are still running the business.

What you will be asked to provide

Financial Information

Historic accounts (typically last 3 years)
Monthly management accounts
Forecasts and budgets
Debtor, creditor, and fixed asset reconciliations
Working capital analysis
Customer and revenue analysis
Explanations for any normalisation adjustments claimed

Legal and Contracts

Key customer and supplier contracts
Employment contracts and HR records
Property leases
IP documentation (trademarks, patents, domain registrations)
Corporate records (articles, shareholder agreements, board minutes)
Any litigation or disputes

Tax and Compliance

Corporation tax returns and HMRC correspondence
VAT records
PAYE and payroll documentation
Any outstanding tax matters or disputes

Operations and Commercial

Customer pipeline and sales process
Key supplier relationships and dependencies
Systems and technology stack
Regulatory licences or accreditations
Insurance policies

The reality of the workload

Document gathering — hundreds of individual items to locate, organise, and upload to a data room
Q&A cycles — buyers send written questions in batches, often 3–5 business days per round, and there are usually multiple rounds
Management meetings — expect 4–8 deep-dive calls or workshops with the buyer's team over the diligence period
Follow-up evidence — after meetings, buyers often come back asking for reconciliations, customer-by-customer detail, or proof for claims you have made

Time commitment: Most sellers find due diligence becomes almost a second job for 6–10 weeks. If you are handling it all personally, expect evenings and weekends spent uploading documents, answering queries, checking numbers, and preparing for calls.

The SPA and Legal Documents

The Share Purchase Agreement (SPA) is the main contract governing the sale. It is typically 40–80+ pages and covers:

Price — the headline number and how it is calculated: enterprise value, equity value, cash-free / debt-free basis, locked box vs completion accounts
Warranties — your formal promises about the business (financial position, contracts, compliance, no hidden liabilities). These are extensive — often 30–40 pages
Limitations of liability — caps, time limits, de minimis thresholds, and disclosure process for warranty claims
Restrictive covenants — what you cannot do after the sale (typically non-compete and non-solicit for 6–24 months)
Deferred / earn-out mechanics — if part of the price is deferred or conditional, this section defines how it is calculated and paid

Disclosure letter: You will prepare a detailed disclosure letter that formally discloses known issues against the warranties. This requires careful cross-referencing to the data room and close coordination with your legal and financial advisers.

Ancillary documents: You will also sign board and shareholder resolutions, stock transfer forms, potentially a tax deed, and often a transitional services or consultancy agreement if you are staying on post-completion.

Negotiating the SPA

Your solicitor will mark up the buyer's draft and negotiate on your behalf
Key battlegrounds: warranty scope, liability caps, indemnities for specific risks, and earn-out conditions
This process runs in parallel with due diligence and is heavily influenced by issues that surface in the data room
Expect 2–4 or more rounds of legal mark-ups

Typical Timeline

For a well-run mid-market SME deal, the timeline typically looks like this:

Stage	Duration	Your time commitment
Indicative offer discussions	1–3 weeks	Light — a few calls and emails
Heads of Terms negotiation	1–2 weeks	Moderate — commercial decisions on structure and price
Due diligence	6–8 weeks	Heavy — 10–20+ hours per week on top of day job
SPA negotiation	6–8 weeks (parallel)	Moderate — reviewing drafts, deciding on red lines
Completion	1–2 weeks	Light — signing documents, final approvals
Total	3–4 months	Peak intensity during due diligence

Slower or more complex deals can stretch to 6+ months, particularly if:

Your financials need cleaning up before or during the process
There are property, IP, or regulatory complications
The buyer's funding is uncertain or conditional
Earn-out mechanics are complex or heavily negotiated

What It Costs

Professional fees for selling a business typically include the following. These are real-world ranges — actual costs depend on deal size, complexity, and which advisers you use.

Legal fees (your solicitor)

Small / straightforward deals (up to ~£500k): £8k–£15k + VAT
Mid-market SME deals (£500k–£2m): £15k–£25k + VAT
Larger or complex deals (£2m+): often ~1% of deal value — £25k–£75k+ + VAT
City or top-tier firms and complex structures push fees higher

Tax and accountancy support

Additional accountant fees for data room preparation, diligence support, and tax planning: £2k–£7k typically for smaller deals
Full vendor tax due diligence (if commissioned separately): mid-five figures upwards on larger deals

Financial adviser / fractional FD

Project-based support for diligence coordination, financial Q&A, and SPA financial sections: typically £10k–£25k depending on intensity and deal size
Some advisers include a small success-based element aligned to deal completion

Business brokers / M&A advisers

Typically a percentage of consideration — often 3–10% on smaller deals, lower on larger deals
Not relevant if a buyer has already approached you directly

Where an Adviser or Fractional FD Takes the Load

If you are handling everything yourself, the biggest drain is due diligence and financial negotiation. Here is where a good fractional FD or transaction adviser makes the difference — and pays for itself.

Before due diligence starts

Clean up and normalise your management accounts so the story is clear and defensible
Identify and quantify adjustments to EBITDA — one-offs, owner costs, non-recurring items
Build credible forecasts that buyers will trust
Anticipate difficult questions and prepare evidence in advance

During due diligence

Own the data room — structure it, track requests, coordinate with your accountant, ensure uploads are complete and consistent
Handle financial Q&A — attend buyer calls, answer detailed questions, prepare reconciliations and bridges (revenue, EBITDA, working capital)
Project manage the process — keep the buyer moving, protect your time, make sure nothing falls through the cracks
Act as financial translator — turn your business story into the KPIs, trends, and metrics buyers expect to see

During SPA negotiation

Support your solicitor on financial sections of the SPA: price mechanism, completion accounts vs locked box, earn-out terms
Help you push back on spurious price adjustments or unfair warranty and liability terms tied to the numbers
Confirm that commercial terms agreed at Heads of Terms are actually reflected in the SPA

Protecting the business throughout

Keep the day-to-day running smoothly — the worst outcome is for the business to deteriorate during the sale process, which can kill the deal or reduce the price
A good adviser shields you from low-value requests and ensures you are only pulled in where genuine commercial judgement is needed

Key Takeaways

1. Selling a business is a 3–4 month intensive process on top of your normal job, with the heaviest load during due diligence.
2. Due diligence is where most sellers get overwhelmed — expect hundreds of document requests, multiple Q&A rounds, and several deep-dive meetings.
3. The SPA is complex and heavily negotiated — warranties, liability caps, and earn-out terms can significantly affect your outcome and your future risk exposure.
4. Professional fees are material but predictable — budget £15k–£35k for legal and accountancy, plus £10k–£25k for a fractional FD or financial adviser on a typical mid-market deal.
5. The right support at the right time pays for itself — either by protecting deal value, reducing your personal burden, or both.

Published by Eranos · April 2026

What to Expect When Selling Your Business