Customer Concentration — Why a Buyer Will Scrutinize Where Your Revenue Comes From

A business is at a disadvantage when a large share of its revenue comes from a small number of customers. Retail businesses (restaurants, shops, stores) typically don't have this problem since they serve many customers; some professional service firms do (specialized engineering or consulting) while others don't (tax prep, insurance).

Why it matters: The worst case is concentration of one — a single customer accounts for most or all revenue. That simplifies operations but creates serious risk if that relationship ends. A buyer will scrutinize this closely; a business built around one or two accounts is harder to sell and often commands a lower price. This is one of the first things a buyer's due diligence team pulls apart — they'll ask for a customer-by-customer revenue breakdown going back several years, then stress-test what happens to cash flow if the top account walks. If concentration is high, expect it to show up in the deal structure itself: a lower multiple, a larger earnout tied to customer retention, or a request for extended seller involvement post-close to help preserve the relationship during transition. Sellers who know their concentration numbers ahead of time — and who can show diversification efforts already underway — tend to negotiate from a stronger position than those who get the number for the first time from a buyer's spreadsheet.

Example (illustrative only): A commercial janitorial company generates 55% of its revenue from a single office park management contract, renewed annually with no long-term agreement. A buyer might still make an offer, but structure it with a lower upfront payment and a two-year earnout tied to that contract renewing — shifting the concentration risk back onto the seller rather than absorbing it entirely at close. (Example: businesses built on Amazon's DSP delivery program aren't contractually barred from serving other customers, but most don't — and Amazon can cancel the agreement at any time without cause.)

Related terms: Due Diligence, Earnout, Reps and Warranties