Due diligence is the investigation a buyer (or investor) carries out before a deal, to verify what they are buying and uncover risks. In an acquisition, due diligence shapes the price, the warranties and indemnities, the conditions, and even whether the deal proceeds. Here is a plain-English guide for England and Wales.
Why due diligence matters
When you buy a business (especially the shares in a company), you generally take it as it is, with its liabilities and history. Due diligence is how you look under the bonnet: to confirm the business is what the seller says, to price the risk, and to decide what protections (warranties/indemnities) you need. The findings flow straight into the negotiation.
The main due diligence "workstreams"
A thorough due diligence exercise usually covers several areas:
- Legal, the company's constitution, ownership of shares, key contracts (and change-of-control clauses), litigation/disputes, regulatory compliance, and corporate records.
- Financial, the accounts, profitability, cash flow, debt, working capital and the quality of earnings.
- Tax, the company's tax position, compliance, and any historic liabilities or risks (feeding into the tax deed/covenant).
- Commercial, the market, customers, suppliers, contracts, and the business's competitive position.
- Intellectual property, ownership and protection of trade marks, patents, copyright, software and know-how (e.g. whether IP was properly assigned by contractors).
- Real estate / property, title to, and terms of, owned and leased premises (see commercial-property due diligence).
- Employment, staff, contracts, benefits, pensions, disputes, and TUPE implications.
- Data protection & IT, UK GDPR compliance, key systems and cyber risk.
- Environmental & ESG, environmental liabilities and increasingly ESG (environmental, social and governance) factors.
- Regulatory, sector-specific licences and approvals, and competition/national-security clearances.
How it works in practice
- The buyer sends a due diligence questionnaire (and request list); the seller populates a data room with documents.
- The buyer's advisers (lawyers, accountants, others) review the material and produce due diligence reports, often highlighting red flags and recommendations.
- Findings are used to renegotiate price, demand specific indemnities, set conditions, or (occasionally) walk away.
Vendor due diligence
Sometimes the seller commissions its own vendor due diligence (VDD) report in advance, to present a clean, ready-made picture to bidders, speed up the process and support the price. Buyers still usually do their own confirmatory checks.
Practical tips
- Scope it sensibly, focus effort on the material risks and the value drivers, not every trivial point.
- Use the right advisers for each workstream.
- Link findings to the contract, turn risks into warranties, indemnities, price adjustments or conditions.
- Keep records of what was disclosed (the disclosure letter interacts with due diligence).
Key takeaways
- Due diligence is the buyer's pre-deal investigation to verify the target and price the risk.
- It spans multiple workstreams, legal, financial, tax, commercial, IP, property, employment, data/IT, environmental/ESG and regulatory.
- It runs through a questionnaire, data room and due diligence reports, and feeds directly into price, warranties, indemnities and conditions.
- Sellers may run vendor due diligence to streamline a sale, but buyers still do their own checks.
Sources
- Standard M&A due diligence practice in England & Wales (workstreams; data rooms; due diligence reports)
- Interaction with warranties, indemnities, the disclosure letter and the tax deed in share/asset purchase agreements
- TUPE 2006 (employees); UK GDPR (data protection); sector and competition/national-security clearances (NSIA 2021)
--- This article is general information about the law of England & Wales as at 2026, not legal advice. For advice on your circumstances, consult a qualified solicitor.