Legal Due Diligence UK: Share & Asset Sale Guide
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When you are buying a company or its business, what you do not know can genuinely hurt you. Legal due diligence is the structured investigation a buyer carries out before committing to a deal, and in most transactions it is where the real protection happens.
The seller's warranties in the sale agreement matter, but they are no substitute for looking under the bonnet yourself. In a share purchase you take the company with every skeleton in its cupboard, so the investigation tends to be wider and deeper than in an asset deal where you can pick and choose what you acquire.
This guide walks through how enquiries are structured in England and Wales, what buyers typically ask for, and where the common traps sit. It is written for buyers, founders selling their business, and advisers who want a practical overview rather than a textbook.
Overview
Legal due diligence is the process of asking the seller detailed questions about the target company or business, reviewing the documents and information they provide, and flagging anything that could affect value, risk, or the structure of the deal. The output is usually a written due diligence report prepared by the buyer's solicitors, summarising findings and highlighting issues that need fixing, pricing in, or protecting against through warranties and indemnities in the sale and purchase agreement (SPA).
The scope depends on the type of transaction. In a share sale, the buyer acquires the legal entity and inherits every contract, liability, claim, and historic tax position attached to it. In an asset or business sale, the buyer cherry-picks specified assets and assumes only those liabilities it agrees to take on, which tends to narrow the enquiries but raises fresh issues around employee transfers under TUPE and third-party consents.
The overarching principle in English law is caveat emptor, buyer beware. The seller has no general duty to volunteer bad news, so if you do not ask the right questions you may have no remedy later.
Key steps
- Agree the scope and sign an NDA. Before the seller hands over sensitive information, the parties usually sign a confidentiality or non-disclosure agreement. The buyer's advisers then agree the scope of the investigation with their client, factoring in deal size, sector, and any known risk areas such as regulated activities, data protection, or significant customer contracts.
- Issue the due diligence questionnaire. The buyer's solicitors send a detailed enquiry list covering corporate matters, contracts, property, employment, intellectual property, disputes, tax, regulatory compliance, and data protection. The questionnaire is tailored to the target, and it is common to issue supplemental enquiries once initial responses and documents have been reviewed.
- Review disclosures in the data room. The seller uploads responses and supporting documents to a virtual data room. The buyer's team works through the materials methodically, checking that answers match the documents, that contracts are signed and in force, and that anything unusual, such as change-of-control clauses, is flagged for the deal team and the client.
- Produce the due diligence report. Findings are written up in a report that identifies material risks, red flags, and items needing further action. The report typically recommends where warranties, indemnities, price adjustments, retention accounts, or conditions precedent should be used in the SPA to allocate risk between buyer and seller.
- Reflect findings in the transaction documents. Issues uncovered during due diligence feed directly into negotiation of the SPA and the disclosure letter. The disclosure letter is the seller's opportunity to qualify the warranties, and the buyer must read it carefully because anything properly disclosed generally cannot be claimed for later.
Common questions
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £89.
Common questions
Q What is the difference between legal, financial, and commercial due diligence?
Legal due diligence focuses on contracts, corporate structure, litigation, regulatory compliance, property, employment, and intellectual property. Financial due diligence looks at the numbers, including earnings quality, working capital, and tax. Commercial due diligence tests the market position and growth assumptions. On most transactions all three run in parallel, and findings in one stream often prompt follow-up questions in another.
Q Why does due diligence matter more in a share sale than an asset sale?
In a share sale the buyer steps into the shoes of the existing shareholders and inherits the company as it stands, including historic tax, pensions, litigation, and contractual liabilities. In an asset sale the buyer selects which assets and liabilities to take, so exposure to legacy issues is narrower. That inherited risk is why share deal enquiries tend to be broader and more forensic.
Q How long does legal due diligence take?
Timing depends on the size and complexity of the target. A straightforward owner-managed company might be investigated in three to six weeks, while a larger or regulated business can take several months. Delays often come from slow seller responses, incomplete data rooms, or issues that need deeper investigation, such as unclear IP ownership or unresolved disputes.
Q What is a disclosure letter and why does it matter?
The disclosure letter sits alongside the SPA and qualifies the warranties the seller gives about the target. If a matter is fairly disclosed in the letter, the buyer usually cannot bring a warranty claim based on it afterwards. This is why reviewing disclosures carefully during due diligence is critical, because the buyer is effectively accepting those risks at completion.
Q What are common red flags uncovered during due diligence?
Frequent issues include change-of-control clauses in key customer contracts, missing board minutes, unregistered intellectual property, historic employment claims, unpaid or disputed tax positions, lapsed licences, data protection gaps, and property title problems. Any one of these can affect price, deal structure, or the warranties and indemnities the buyer will insist on in the SPA.
Q Do I still need warranties if I have done thorough due diligence?
Yes. Due diligence uncovers what the seller chooses to disclose and what your advisers can identify from the documents provided. Warranties act as a contractual safety net for matters that were not apparent at the time, and indemnities are used where a specific known risk needs to sit with the seller. The two work together rather than as alternatives.
Q Can the buyer walk away if due diligence uncovers something serious?
Until the SPA is signed, the buyer is generally free to walk away, renegotiate price, or restructure the deal. After exchange, the buyer is usually committed unless the SPA contains specific conditions precedent or termination rights tied to the issue in question. That is why material findings should be addressed before signing, not left to be argued about afterwards.
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £89.
Sources
This guide is based on primary UK law and official guidance.
- Guidance · Companies HouseCompanies House – search the registerfind-and-update.company-information.service.gov.uk
- Guidance · Companies Housegov.uk – company filing requirementsgov.uk
- Guidance · UK Govgov.uk – TUPE transfer of employeesgov.uk
- Guidance · HMRCHMRC – Stamp Duty on sharesgov.uk
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Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.