Diligence is not about confirming what you already believe. It is about creating the conditions under which someone can tell you an uncomfortable truth before you sign — because after you sign, the same truth becomes your problem to fix.
Whether you are acquiring a company, taking a stake, or picking a local partner to enter a new market, the patterns that cause trouble are remarkably consistent. Below are five we encounter more often than any others, together with the single diagnostic question that tends to surface each one. None of these is proof of wrongdoing on its own. Each is a prompt to keep pulling the thread until you are satisfied.
1. Opaque or shifting ownership
When the answer to "who ultimately owns this?" arrives slowly, changes between conversations, or routes through layers whose purpose no one can plainly explain, treat it as a signal rather than an administrative quirk. Legitimate structures have legitimate reasons that a director can articulate without hesitation.
Ask: can you walk me through the full ownership chain to the ultimate beneficial owners, and explain why each layer exists?
The most expensive surprises are rarely hidden in the numbers. They sit in the assumptions no one thought to question — the ones everyone treated as settled precisely because no one had checked.
2. Financials that don't reconcile
Small discrepancies are normal; a story that only holds together at a distance is not. When management accounts, statutory filings and bank reality tell three slightly different versions of the same year, the gap between them is where your risk lives.
Ask: can you reconcile the management accounts to the filed statements and to the bank statements, line by line, for the last two periods?
3. Regulatory and licensing gaps
In regulated sectors, operating without the right permissions — or on permissions that are lapsed, informal, or held by the wrong entity — is a liability that transfers to you on completion. The problem is often not that a licence is missing, but that everyone assumed someone else had confirmed it.
Ask: which activities require authorisation, which entity holds each one, and can you show me the current, valid documents?
4. Customer concentration
A business that leans heavily on a handful of relationships is only as stable as those relationships, and revenue figures alone will not tell you how fragile they are. Concentration is not always a dealbreaker — but it changes what you are actually buying.
When you find concentration, look past the headline and test its durability:
- How long has each major account been on the books, and is the trend up or down?
- Are the relationships contractual, or handshake arrangements that could walk?
- Do those customers depend on one person rather than the company?
- What happens to the model if the largest account leaves within a year?
Ask: if your two largest customers left, what would the business look like twelve months later?
5. Key-person dependence
Sometimes the company is, in practice, one person — the founder who holds every relationship, every password and every judgement call in their head. When that person is also the one selling, you need to understand what remains once they step back.
Ask: if the founder were unavailable for three months, which functions would simply stop?
What to do when a red flag appears
A red flag is a prompt to dig, not an automatic reason to walk away. The right response is to keep asking until the flag either resolves into a reasonable explanation or hardens into a real risk you can price, cover with warranties and indemnities, structure around, or decline. What you must not do is note the flag, feel reassured that you spotted it, and move on. Diligence earns its cost only when the awkward questions are actually asked — and answered — before the capital leaves your account.