M&A Due Diligence Checklist: 50-Point Framework for Buy-Side Teams
The complete due diligence checklist for M&A transactions. 50 essential checks covering legal, financial, commercial, HR, and compliance — with explanations for each.
Mergers and acquisitions fail for many reasons, but one of the most preventable is inadequate due diligence. The deal that looks compelling in the teaser document often looks very different when you dig into the data room. Legal liabilities, accounting irregularities, customer concentration risks, compliance failures, and undisclosed debts — these are the findings that transform a 5x EBITDA opportunity into a problem asset.
Due diligence is the systematic investigation of a target company by a potential acquirer before signing a purchase agreement. It is not a tick-box exercise — it is risk discovery. The goal is not simply to confirm what the seller told you but to find what they didn't tell you.
This guide provides a 50-point due diligence framework organized across five workstreams: legal, financial, commercial, operational/HR, and compliance. For each area, we identify the key items, what to look for, and why it matters.
Common Red Flags in M&A Due Diligence
Reluctance to open the data room: Sellers with nothing to hide open their data rooms fully. Excessive redactions, slow responses to information requests, or arbitrary restrictions on access to certain categories of documents are significant warning signs.
EBITDA that appears too clean: Real businesses have messy financials — one-time costs, litigation provisions, restructuring charges. An EBITDA that is uniformly smooth and growing is often the result of aggressive normalization adjustments. Scrutinize every add-back.
Customer contracts that expire soon: If the majority of revenue-generating customer contracts expire within 12 months of closing, the revenue quality is much lower than the headline number suggests — especially if renewal rates are uncertain.
Undisclosed related-party transactions: Transactions between the target and entities owned by the seller, management, or their families may be above-market (inflating revenues) or below-market (disguising cost inflation). All related-party transactions must be identified and assessed.
Frequent auditor changes: Replacing auditors more often than once every 5-7 years can indicate disagreements over accounting positions, a pattern associated with financial reporting risk.
Normalized EBITDA significantly exceeding reported EBITDA: When the seller claims a normalized EBITDA that is materially higher than what has actually been reported to tax authorities, the normalization deserves intense scrutiny. Tax returns and management accounts should be consistent.