Customer concentration is one of the most consequential financial red flags in M&A, and the threshold deal teams watch is when a single customer represents more than 20% of revenue. At that level, the business's health is bound to one relationship — and the loss of that customer, whether from dissatisfaction, their own troubles, or a reaction to the acquisition itself, would crater the target's economics.
Why the Threshold Matters
A business with diversified revenue across many customers is resilient — losing any one is survivable. A business where one customer is 20%, 30%, or more of revenue is fragile in a way the aggregate numbers hide. The buyer isn't just acquiring a revenue figure; they're acquiring a dependency. Concentration directly affects pricing and deal structure: it pushes valuation down, drives more aggressive earnout and indemnification terms, and sometimes makes the buyer require the concentrated customer relationship be secured before close.
How It Compounds With Other Flags
Concentration becomes more dangerous when it intersects with other red flags. If the concentrated customer's contract contains a change-of-control provision, the acquisition itself could trigger their right to leave — converting a concentration risk into an immediate post-close revenue loss. If the contract is short-term or up for renewal, the dependency is even more acute. This is why concentration analysis reads the actual customer contracts, not just the revenue summary.
Surfacing It in the Data Room
Finding concentration requires reading the revenue detail and cross-referencing it against the customer contracts for term, renewal, and change-of-control exposure. The AI agent reads both the financial detail and the underlying contracts, surfacing concentration and flagging where it intersects with contractual risk. It's demonstrated at omnionlinestrategies.com/ai-agent-ma-due-diligence.