Customer concentration

Customer concentration is the degree to which a company’s revenue depends on a small number of customers. In M&A it matters because it affects perceived business risk: the higher the concentration, the greater the impact of losing a key customer on EBITDA and cash flow, and the lower the buyer’s willingness to pay the same multiple or to structure the deal with less contingent consideration. Buyers and their advisors use reference thresholds (e.g. one customer with more than 20–25% of revenue as a flag, more than 40% as serious risk) to adjust valuation, require earn-outs or seller retention, and deepen due diligence on contracts and relationships with those accounts.

What concentration thresholds do buyers use?

There is no single standard; in Mexican SME and mid‑market transactions usual references apply. A customer that contributes more than 20–25% of revenue triggers specific questions in due diligence: contract stability, relationship with the decision‑maker, renewal history. Above 40% from a single customer, risk is considered high: the buyer adjusts price (lower multiple), requires a larger earn-out tied to retaining that account, or conditions closing on the seller staying through a transition. Top‑3 concentration is also reviewed; if the three largest sum to more than 50–60% of revenue, the business is treated as concentrated and deal structure and valuation reflect that risk.

How does concentration affect the multiple, deal structure, and due diligence?

The buyer values off normalized EBITDA; if that EBITDA can collapse when one or two customers leave, the value they are willing to pay goes down. In practice that means:

A seller who prepares a concentration analysis, documents account stability, and offers an orderly transition can soften the penalty. To see how these discounts show up in the Mexican market, see why SME multiples in Mexico are lower.

To estimate impact on EBITDA‑based value, the buyer decides the multiple from its assessment of concentration risk. In due diligence revenue by customer and contract quality with main accounts are validated.

What does customer concentration look like in a Mexican transaction?

Illustrative example (B2B services, Mexico, anonymized): a specialized services company with annual revenue of MXN 28,000,000.00 and normalized EBITDA of MXN 4,200,000.00 had customer A at 38% of revenue (MXN 10,640,000.00), customer B at 22% (MXN 6,160,000.00), and the rest spread across 15+ accounts.

It received two offers with different multiple and structure; the comparison summarizes the effect of concentration on terms:

The seller chose the first offer for higher certainty at closing and accepted a 12‑month transition period to support the relationship with A and B. Concentration did not kill the deal but it set the multiple and the structure.

What do buyers and sellers ask about customer concentration?

What concentration threshold worries a buyer in Mexico?

In Mexican SME practice, a single customer representing more than 20–25% of revenue is considered a focus point: the buyer will dig into contract stability and the relationship. Above 40% from one customer, risk is considered serious and typically leads to a lower multiple, a larger earn-out tranche, or a requirement for seller retention to ensure transition. The top‑3 customers combined are also analyzed; if they exceed 50–60% of revenue, the profile is treated as concentrated.

How does concentration affect the EBITDA multiple offered?

At the same normalized EBITDA, a highly concentrated business gets a lower multiple than a diversified one. The buyer discounts the risk that losing one or two key customers will tank the result. The size of the discount depends on sector, contract quality, relationship length, and whether the seller stays for transition. In some cases the buyer keeps the multiple but shifts value into an earn-out tied to retaining those customers.

Does concentration always hurt the seller in negotiation?

Not necessarily. If contracts are long‑term, renewable, and with institutional or low‑churn customers, the buyer may accept moderate concentration without punishing price. What hurts is concentration combined with owner‑seller dependency in the relationship, short or verbally renewed contracts, or highly competitive sectors where the customer can switch suppliers easily. The seller should prepare a concentration analysis and argue the stability of each key account.

What should the seller prepare in due diligence on concentration?

Revenue history by customer (at least 24–36 months), copies of framework contracts or recurring orders with main customers, term and renewal conditions, and if applicable letters of intent or customer commitments. The buyer will verify that declared revenue matches the contracts and that there are no easy termination clauses or informal dependencies. Well‑documented concentration with solid contracts negotiates better than opaque concentration.