How much customer concentration is too much?

Buyers ask this question expecting a specific percentage, and the honest answer is that no single number determines whether concentration is a problem — the same percentage means something different depending on how replaceable that revenue actually is once ownership changes hands.

Why the percentage alone is the wrong question

A business earning a meaningful share of revenue from one customer under a long, exclusive, transferable contract carries a different risk than a business earning the same share from a customer who could switch suppliers with a phone call. Lenders and valuators look past the raw number to how durable and transferable the relationship actually is before deciding how much risk it represents.

What actually gets scrutinized

• How long the relationship has existed and whether it survived a change in pricing or terms before
• Whether the relationship is documented in a written, assignable contract, or rests on personal rapport with the current owner
• Whether the concentration is trending up or down over the years the seller has owned the business
• How much of the business’s overhead and staffing is tied specifically to serving that one customer

How it shows up in price and financing

Concentrated revenue typically compresses the multiple a buyer is willing to pay, because more of the historical earnings is treated as at risk rather than durable, and a lender assessing cash flow for a loan applies the same logic when deciding how much of that revenue to count on. This is a pricing input, not an automatic disqualifier — many good businesses have one large customer and are priced accordingly.

What to do about it as a buyer

Rather than treating concentration as a single number to accept or reject, ask what would actually happen to the business if that customer left — whether the relationship transfers to you personally, whether a transition plan exists, and whether the price already reflects that risk. That answer matters more than the percentage on its own.