How dependent is your business on one customer? Run a revenue and cash stress test
Calculate customer concentration, separate lost work from delayed collections and choose a practical response using a clearly fictional business example.
Share this guide
A valuable account can also create a planning constraint
A large customer can bring repeat work, useful feedback and a more predictable schedule. The question is not whether the account is good or bad. It is what would happen if its work slowed down, stopped or paid later than expected. Those are different events, and each deserves its own test.
SBA's finance guidance stresses bookkeeping and the management of receivables and available cash. Its market-research guidance helps frame the separate question of where additional demand might come from. The stress test below is BGA's original planning method. It does not prescribe a universal safe concentration percentage.
Measure dependence using a consistent period
List revenue by customer for the same period, then divide the largest customer's revenue by total revenue. Repeat for the largest few customers. Use a period that reflects how the business actually operates; compare a recent quarter with a longer period if seasonality or a one-time project could distort the picture.
Check whether several account names depend on the same underlying buyer or budget. A business with five locations may still expose you to one purchasing decision. Also record work already committed, unpaid invoices and known upcoming changes. Keep sensitive customer records inside the authorized business system; the review does not require public disclosure.
Model lost work separately from lower profit
Assume a fictional company earns $60,000 in monthly revenue, of which one customer accounts for $24,000. The concentration is 40%. Suppose total variable delivery costs are $30,000 and fixed costs are $24,000, leaving a simplified $6,000 operating remainder before other obligations. These are invented assumptions, not an industry benchmark.
Now assume the large customer's work disappears and $14,000 of its associated delivery costs can genuinely be avoided in the same period. Remaining revenue is $36,000 and remaining variable costs are $16,000. That produces $20,000 before fixed costs, or a $4,000 shortfall against the assumed $24,000 fixed cost base.
The lost contribution is $10,000, not the full $24,000 of revenue. But the result depends on the cost assumption: wages, minimum purchases and other commitments might not fall immediately. Run a second version with fewer avoidable costs when that better matches reality. Do not describe a hoped-for cost cut as money already saved.
Test a payment delay without removing the sale
For a separate fictional cash scenario, start with $20,000 available and expect $60,000 in collections during the month. Assume $54,000 of cash outflows are due in that month. The expected ending balance is $26,000. If the large customer's $24,000 payment moves to the next month, current collections fall to $36,000 and the ending balance falls to $2,000.
This delay does not itself mean the sale vanished or the invoice is uncollectible. It changes the timing of available money. Check the actual payment terms, invoice status and expected collection date before acting. Use BGA's four-week cash-flow guide to place receipts and obligations on the calendar rather than relying only on a monthly total.
Choose a response that fits the exposure
A reasonable response may be to keep the account and improve visibility: confirm the next order date, review invoice accuracy and know who can resolve a billing question. For a concentrated delivery schedule, identify which resources could serve other customers if demand changed. Do not promise to replace the work immediately without evidence of demand and capacity.
If diversification is warranted, define the type of customer and work that would reduce the dependence. Ten new small jobs with poor economics may not improve the position. Use the acquisition-cost and capacity guides to test whether the proposed replacement work can be won and fulfilled responsibly.
Record the scenario, assumptions, earliest warning signal, person responsible and next review date. Revisit the test when a major order, payment pattern or customer relationship changes. The useful outcome is a documented decision and contingency, not a percentage displayed on a dashboard without anyone knowing what to do about it.
Original sources
Share this guide