The Concentration Conversation: A Boardroom Test for Client Dependency

In 2026, growth is welcome but it can conceal risk. A UK firm wins a large client, delivers well and sees revenue rise. The client renews, refers the firm to a sister company and gradually becomes the reference point for the firm's reputation. None of this feels dangerous. It feels like success. Then the client changes procurement leadership, pauses a programme or moves to a competitor, and the firm discovers that one relationship has become a structural exposure.

Client concentration is rarely a sudden event. It creeps. The purpose of a boardroom conversation about concentration is not to reject valuable clients. It is to decide, explicitly, how much dependency the firm is prepared to carry and what it will do when that limit is approached.

Start with a provocative threshold

A useful debate begins with a deliberately blunt question: should any single client be allowed to account for a quarter of the firm's revenue? There is no universal answer. A 25 per cent threshold may be too high for a small specialist consultancy and too low for a capital-intensive supplier with long contracts. The number matters less than the discipline of asking. It forces partners and directors to distinguish between a client that is important and a client that is systemically important.

Concentration should be measured on more than revenue. A client may represent 15 per cent of turnover but 30 per cent of gross margin, 40 per cent of partner time or the majority of the firm's pipeline. It may dominate one office, one service line or one sector. The board should therefore ask four questions: how much revenue, how much profit, how much capacity and how much reputational dependence does this relationship represent? The answers rarely point in the same direction, and that is precisely why the conversation is useful.

The warning signs of quiet dependency

The most reliable warning sign is not a number on a management account. It is behaviour. The firm starts to organise around the client: recruitment, systems, account planning and partner diaries all bend towards the relationship. Requests that would be challenged elsewhere are absorbed as 'strategic'. Payment terms slip but the firm says nothing. The client's roadmap becomes the firm's roadmap. When the renewal date approaches, the whole business feels the tension.

Other signs are more measurable. The top client appears disproportionately in pipeline forecasts. New business from other clients is thin. The same relationship partner handles the account with little succession. Key knowledge sits with a small team. The client has become, in effect, the firm's most important internal project without ever being labelled as such.

Why concentration creeps up during good years

Concentration is a by-product of success. A growing client buys more, pays on time and refers others. The firm allocates its best people to the relationship because that is where the revenue is. Sales incentives reward account growth. Reporting celebrates total revenue rather than revenue diversity. Nobody wants to slow down a good client, so the issue is deferred until a shock forces it onto the agenda.

There is also a cultural reason. In professional and specialist firms, partners are trained to build deep relationships. Deep relationships naturally create dependence. The firm may be reluctant to introduce guardrails because it fears appearing ungrateful or overly corporate. The result is a governance gap: the client is discussed in account reviews but not in risk reviews.

De-risking without walking away

The good news is that de-risking does not require abandoning a valuable relationship. It requires a portfolio plan. The board can begin with a concentration dashboard, reviewed quarterly, covering revenue, gross margin, work in progress, debtor days and pipeline by client. The dashboard should show the top ten clients and the pace of change, not just the year-end position. A rising line is more informative than a static percentage.

Next, set guardrails. A soft threshold, perhaps 20 per cent, might trigger a discussion at the board; a hard threshold, perhaps 30 per cent, might require a written mitigation plan. These are not caps to be enforced by ending contracts. They are triggers for action. The plan could include a target for new business from outside the top client, a requirement that no single client dominate more than a set share of the pipeline, or a limit on the proportion of a delivery team assigned to one account.

Contract terms can also reduce exposure without damaging the relationship. Firms should review renewal cycles, notice periods, payment terms, change control, liability caps, intellectual property and exclusivity. A contract that is commercially fair but structurally flexible is better than one that is simply long. Where possible, avoid arrangements that make the firm's capacity or IP dependent on one client's continued custom.

Operationally, the firm can build redundancy. Rotate staff, document client knowledge, create a second relationship sponsor and ensure that key decisions are not held by one partner. This is not about distancing the client. It is about making the relationship resilient enough to survive a change of personnel on either side.

Put the question on the agenda

Finally, test the scenario in the room. Ask what would happen if the top client gave notice tomorrow. How quickly would cash flow tighten? Which roles would be exposed? What would the firm stop doing, and what would it accelerate? A board that can answer those questions calmly is better prepared than one that discovers the answers during a crisis.

A concentration threshold is not a rule imposed from outside. It is a decision the firm makes about its own appetite for risk. The right number will differ by firm, sector and stage of growth. But the conversation should not be left until a client owns too much of the business. By then, the firm is no longer debating a threshold; it is negotiating from a position of dependency.