What legal due diligence in an M&A deal involves
Before a company changes hands, lawyers pull it apart on paper. A guide to what due diligence looks for and why it shapes the whole transaction.
When one company buys another, the deal that reaches the headlines is the product of weeks of unglamorous investigation. Legal due diligence is the process by which a buyer’s lawyers examine the target business in detail before committing, to understand what is actually being bought, what risks come with it and what the buyer should be protected against. It runs alongside financial and commercial due diligence, and its findings shape the price, the structure and the terms of the final agreement.
The exercise typically begins with the buyer’s advisers issuing a due diligence request list and the seller populating a data room with the documents that answer it. From there the review fans out across the areas of law that touch a business. Corporate due diligence checks that the target is properly constituted and that its shares are validly held and can be transferred. Contract review looks at the key commercial agreements, particularly for change-of-control clauses that let a customer or supplier walk away when ownership changes hands. Employment work maps the workforce, terms, pension arrangements and any liabilities. Real estate review covers property owned or leased. Intellectual property due diligence confirms the business actually owns or is licensed to use the brands, software and technology it depends on. Litigation enquiries surface disputes, whether current, threatened or merely likely.
Newer categories have become just as important. Data protection due diligence examines how the target handles personal data and whether it is exposed to regulatory risk, and cyber security, sanctions and anti-bribery compliance now feature routinely in any serious review.
What the lawyers are producing is not just a catalogue of problems. Due diligence findings feed directly into the deal documents. Issues that are material but manageable are dealt with through warranties, statements about the state of the business that the seller stands behind, and indemnities, specific promises to reimburse the buyer if an identified risk crystallises. The seller answers the warranties with a disclosure letter, which qualifies them by revealing known exceptions, so a buyer cannot later claim to have been misled about something it was told. A problem serious enough may become a condition to completing at all, or reduce the price, or in the worst case end the deal.
The tone of the process reflects a basic asymmetry: the seller knows the business and the buyer does not. Due diligence exists to close that gap as far as documents allow, and the discipline of it, patient, sceptical and thorough, is a large part of what transactional lawyers are paid for. A deal that skips it, or does it badly, is where post-completion disputes are born.