How Can a Family Office Verify a Private Company's Customer Concentration?

Measure each customer's share of revenue, gross profit, and cash collections. A pitch deck percentage can hide affiliated buyers, timing effects, or a major account whose sales bring in little cash.

Build a Customer-Level Schedule

Request sales by customer for each reporting period, with credits and cash collections. Ask for returns and discounts too. If names are coded for confidentiality, request a consistent code that traces each customer across periods. If needed, request the mapping through an agreed confidential process. Ask how the company groups distributors, resellers, parent companies, and related entities so one economic buyer is not split into several accounts.

Reconcile the schedule to the general ledger. Match invoices to bank receipts. Compare billed revenue with cash collected and outstanding receivables by customer. Look for a customer moved to a new code, a one-time order near period end, a credit issued after the reporting date, or sales routed through an intermediary. Request contracts and amendments for the largest accounts.

Measure Dependence Beyond Sales

Calculate each major account's share of revenue, gross profit, and cash collections. Review payment timing and renewal dates. Check minimum purchase commitments, cancellation rights, price terms, and termination provisions. A high sales share may carry less exposure if the customer has a binding long-term commitment; an account with no commitment and slow payment may carry more.

Check whether multiple buyers depend on one distributor, platform, or channel. Ask whether the customer relationship belongs to the company or rests on one executive's personal connection. Review the products or services sold to each large account. Check whether the company can redeploy related staff or capacity if that account shrinks.

Test the Loss or Reduction Case

Model a major customer reducing purchases, delaying payment, renegotiating price, or leaving. Estimate lost revenue and gross profit, remaining costs, and the time needed to replace the account. Compare that case with available cash and debt payments. Include payroll and other fixed obligations. Ask management which actions it would take first and which costs it can remove.

Ask direct questions and request supporting evidence:

• "How do you define a customer when related entities buy through different channels?"
• "Can we reconcile this schedule to invoices and the ledger, and compare it with cash receipts?"
• "What share of gross profit comes from the largest accounts? What share of cash receipts do they provide?"
• "Which major customers can cancel or reduce orders, and on what terms?"
• "What evidence supports the expected renewal or replacement of a lost account?"

Red flags include unexplained changes in customer coding, sales that cannot be reconciled, rising receivables from a major buyer, or forecasts that assume replacement sales without identified prospects. Follow up on inconsistencies and record each explanation.

Seek Independent Confirmation

Where permitted, speak with customers using consistent questions. Ask what they buy and how the company performs. Ask whether they expect to continue and what alternatives they could use. A friendly reference is one data point, not a commitment. If customer contact is restricted, ask why and what alternative evidence can be provided. Ask whether access can occur later under confidentiality protections.

Keep a record of information from contracts and accounting records. Also record what came from customer conversations and management estimates. For the related question of repeat purchases and committed revenue, see how to test whether revenue is recurring. Review the broader business and ownership picture in what to inspect before buying a private company stake.

Checklist

• Request customer-level sales and receivables schedules. Obtain collections schedules too.
• Reconcile major accounts to contracts and bank receipts. Match invoices as well.
• Aggregate affiliated buyers and shared distribution channels.
• Measure concentration in gross profit and cash, not sales alone.
• Stress test a reduction, delayed payment, or loss of a major account.
• Record customer confirmations and unresolved evidence gaps.

Go deeper: How can a family office uncover liabilities that are missing from a company's accounts?; deal IRR and MOIC calculator.

Sources: Family Office Club investor due diligence framework. Informational only, not financial, legal or tax advice.