The Renewal Season Audit: Testing a Consultancy's Dependence on Its Largest Clients

A consultancy with two dominant clients is not automatically fragile. It may be profitable, focused and well managed. But concentration deserves the same scrutiny as any other balance-sheet risk. In 2026, as clients retain suppliers more carefully and procurement cycles lengthen, the question is not whether concentration is good or bad. It is whether the owners know what would happen if one of those relationships changed.

The answer is often uncomfortable. Two clients can account for a large share of fee income while also absorbing the firm's best delivery staff and the founder's attention. The risk is not simply lost revenue. It is the fixed cost that remains, the team that becomes underused and the cash that arrives later than expected.

The quiet mechanics of concentration

Revenue concentration usually appears in three forms. The first is contractual dependency: a large client may have termination rights, short notice periods or a procurement process that can be reopened at will. The second is key-person exposure: the relationship may depend on one partner, one sponsor or one delivery lead. The third is cash-flow shock: losing a client removes income before the firm can remove cost.

These risks reinforce each other. A notice period may look adequate until it coincides with a quiet quarter. A key person may look replaceable until the client says otherwise. A profitable year may look secure until two large invoices are paid late. UK consultancies often work on monthly retainers, project statements of work or framework agreements. Each model has different exit mechanics, and those mechanics matter more than the headline fee.

A four-part stress test

The test should be done before renewal season, not after a notice letter. It need not be elaborate. It does need to be honest.

1. The revenue and contribution test

Model the loss of the largest client from the first day of next month. Then model the loss of the second. For each scenario, calculate the revenue lost, the gross margin lost and the costs that cannot be removed within 90 days. Compare the result with the firm's cash balance, undrawn facilities and committed liabilities. The purpose is not to predict the future but to identify the point at which the firm would need to act.

2. The contract test

List every large client contract with its renewal date, notice period, termination rights, payment terms, exclusivity and any change-of-control or benchmarking clause. Check whether the contract can be exited at short notice and whether the firm has any protection for work in progress. A contract that renews automatically without a diary reminder is a governance failure waiting to happen.

3. The key-person test

For each dominant client, identify the individual who owns the relationship and the individual who owns delivery. Ask what would happen if either left, took a long period of leave or became unavailable. Is there a second sponsor? Is the delivery knowledge documented? Would the client stay if the named partner moved on? If the answer is uncertain, the firm has a succession issue as well as a concentration issue.

4. The cash-flow test

Build a 13-week cash forecast under the loss scenario. Include payroll, VAT, PAYE, rent, software, subcontractors and any loan repayments. Then apply a realistic delay to the largest debtor. Many profitable consultancies fail this test because profit and cash are not the same thing. A concentration review that ignores working capital is only half a review.

Mitigation before renewal season

The first step is to put concentration on the board agenda. A simple dashboard should show the top two clients as a percentage of revenue, gross margin and cash collected. Set a threshold at which the board must discuss a plan. The threshold is a judgement for each firm, but the number should be explicit rather than discovered after the event.

The second step is contractual hygiene. Diarise every renewal and notice date. Negotiate termination assistance, clear payment terms and, where possible, a transition period that gives the firm time to redeploy staff. Do not assume that a long-standing relationship is a substitute for a clear contract.

The third step is deliberate diversification. A target such as no single client above a set share of revenue can be unrealistic for a specialist firm, but it forces a conversation. The aim is not to reduce a good client. It is to ensure that growth does not quietly create a dependency that the owners would not choose.

The fourth step is liquidity. A cash buffer, an agreed overdraft or a revolving facility can buy time. Credit insurance may be available for some receivables, though it is not a substitute for client due diligence. The firm should also know which costs are genuinely variable and which are fixed.

The difficult judgement

Concentration can be a rational strategy. A consultancy may choose to serve a small number of large clients because the work is profitable and the relationships are strong. That is a legitimate business model. The danger is drift: allowing concentration to build without deciding whether the returns compensate for the risk.

Before the next renewal season, the owners should be able to answer three questions. What share of revenue and margin depends on the top two clients? What happens to cash and staff if one leaves? What will the firm do, and by when, if the answer is worse than expected? A firm that can answer those questions is not immune to concentration, but it is no longer managing the risk by default.