Short answer
Divide the largest customer’s revenue by total revenue for the same period. For the top three, add their revenue before dividing. Where appropriate, group entities dependent on one commercial decision. The percentage describes exposure, not business value, cancellation probability or profit loss.
Key verification: Totals reconcile, groupings are justified and every percentage retains its period and revenue basis.
Sources and limitationsAn agency with many CRM names may depend on few purchasing decisions. Several subsidiaries could cancel together if governed by one contract. When preparing a sale, document this dependence through clear rules. This guide provides an original revenue calculation rather than estimating business price or replacing financial review.
Define the basis before ranking customers
Choose a closed period, such as the last twelve complete months, and use comparable revenue. Reconcile it to your record for that basis; invoices, receipts and service delivery can fall in different periods. Define credit treatment and avoid adding taxes that are not revenue. Include every customer, including small ones, in the denominator.
Fictional example: the largest customer contributes 40%
| Anonymised customer | Period revenue | Share |
|---|---|---|
| A | 40000 EUR | 40% |
| B | 20000 EUR | 20% |
| C | 10000 EUR | 10% |
| Others | 30000 EUR | 30% |
| Total | 100000 EUR | 100% |
Largest-customer share is 40000 / 100000 = 40%. Top-three share is 70000 / 100000 = 70%. If A and B depend on one buying group, that group may represent 60%. Retain both views and grouping rationale; changing the commercial unit must not change total revenue.
Exposure is not automatic loss
Review duration, renewal, notice and scope using authorised documentation. High concentration does not establish that a customer will leave. Lost revenue is not an equal profit loss: delivery costs and capacity can change. For a departure scenario, identify assumptions and distinguish affected revenue from margin and continuing obligations.
Share the measure during a sale
World Businesses For Sale publishes business valuation information. A concentration table supplements commercial documentation; it is not a platform-guaranteed discount or multiplier. Check services and conditions when considering a listing. CallsIQ has neither executed a sale nor validated a marketplace outcome.
Share suitable aggregates publicly; retain names, contracts and transactions for authorised recipients under the agreed access process. An acceptance worksheet should reconstruct totals, top-three positions and any grouping. A customer list without period, basis or reconciliation does not demonstrate economic diversification.
Sources and limitations
Documentary review: . Content type: Documentation-based guide with original exercise.
Sources describe terms and capabilities stated by their owners. Proposed protocols and fictional examples do not establish product tests performed by CallsIQ.
- business valuation informationworldbusinessesforsale.com
Check current terms
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Official sources, explained calculations and clearly labelled examples. Read about our methodology and use of AI in writing.