When one customer is too much of the revenue
Concentration is the first thing a buyer looks for and the hardest thing to fix quickly. What it costs, and what to do if you already have it.
A buyer reads your customer list before he reads your profit. He is looking for one thing first: how much of this goes away if a single relationship ends.
Why it costs more than owners expect
It is not that concentration makes a business bad. It is that it makes the earnings less certain, and a buyer prices certainty. If one general contractor, one property manager or one OEM is a large share of your work, the buyer is underwriting that relationship rather than your company.
Then it hits the financing. A lender looks at the same list and asks what debt service looks like if that customer leaves. Deals that would otherwise fund get structured differently, with more of the price pushed into a seller note or an earnout — which is concentration costing you terms rather than price.
What actually helps
Time helps most, and most owners do not have much of it. What you can do in a year: put the big relationship under a written agreement if it is running on a handshake, deepen the second and third accounts deliberately, and document that the relationship belongs to the company rather than to you personally.
That last one matters more than owners think. A buyer who believes the customer stays because of the company is in a different conversation from one who believes the customer stays because of you.
A Straight Answer
Work out your top customer as a share of revenue before anyone asks. If it is high, say so early and bring the explanation with it. A buyer who discovers it himself in week three prices the surprise as well as the risk.
BuiltEquity is a sell-side brokerage for trades and field-service companies. Nothing here is legal, tax or accounting advice. Your CPA and your attorney are the authority on your situation.