Risk & diligence

Customer Concentration Risk in a Business Acquisition

Measure concentration by revenue and gross profit, test contract and relationship transfer, and model the effect of losing a major customer.

Buyer field note14

A practical research brief from the Business Buyer Check learning library.

10 min readUpdated September 12, 2026Learning Library
Short answer: Measure customer concentration across multiple periods using revenue and gross profit, then review contracts, renewal, termination, assignment, churn, pricing, collections, and owner relationships. Model the loss or repricing of major accounts and connect the exposure to price, financing, retention, and deal protections.

Calculate More Than Revenue Share

Measure the top one, five, ten, and twenty customers by revenue and gross profit. Compare monthly and annual periods so seasonality or one project does not distort the result.

Inspect Contract Durability

Review term, renewal, termination, assignment, change of control, pricing, volume, exclusivity, service levels, warranties, and customer consent. An invoice history is not a transferable contract.

Separate Company Relationships from Owner Relationships

Identify who sells, serves, resolves problems, negotiates price, and holds personal trust. Plan introductions and retention without making unauthorized customer contact.

Test Quality and Collectability

Review churn, cohorts, credits, refunds, chargebacks, disputes, receivable aging, payment terms, and contribution margin. High revenue with weak margin or collections can overstate importance.

Run Loss Scenarios

Model loss, volume reduction, repricing, delayed payment, and replacement costs for major accounts. Recalculate earnings, working capital, DSCR, and buyer return.

Structure Around Exposure

Possible tools include lower price, seller note, earnout tied to retained gross profit, holdback, customer consent, transition support, or a stop rule. Counsel should define enforceable terms and privacy-safe confirmation.

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Frequently Asked Questions

What percentage is too concentrated?

There is no universal threshold. Contract strength, margin, switching risk, relationship ownership, financing, and replacement capacity determine materiality.

Should a buyer contact customers?

Only with seller authorization and a controlled process that protects confidentiality and the business. Review the plan with advisers.

Is recurring revenue always transferable?

No. Recurrence in history does not guarantee renewal, consent, assignability, pricing, or retention after ownership changes.

This educational material is preliminary decision support, not legal, tax, accounting, lending, appraisal, or investment advice. Requirements and transaction terms vary; verify current rules with qualified advisers and official sources.

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