Client Concentration: The Risk That Halves Your Agency's Value

The month before I sold my agency, a long-term client walked in with a brand someone else had designed for them.

They’d been with us for 10 years. And they had no idea we offered branding.

They gave that project to another agency because nobody on my team ever told them what else we could do. That story has more to do with client concentration than you might think.

Two numbers that tell you everything

What percentage of your revenue comes from your top client? And what percentage comes from your top three?

If you don’t know those answers right now, that’s the biggest problem. A buyer will know within the first hour.

During my exit, the buyers asked about client concentration before anything else. Revenue, margins, team structure. All of that came after. Concentration was the first thing they wanted to see.

I now coach agency owners through exit preparation and scaling. Every single one of them, when we first sit down, has a concentration problem they haven’t actually quantified. Once they see the numbers, the conversation changes very quickly.

What concentration does to your business

Your biggest client gets the most attention. They’ve likely been with you some time, you know them personally, and they get the founder’s time. Not only that, they get the best people on their account. They negotiate hardest on price. And the margin on their account? Often the worst in the business.

The headline figure looks great. But the reality is often very different.

Because if that client leaves. Or pauses. Or gets acquired. Or their marketing director changes. Payroll is suddenly tight. You can’t absorb the capacity gap. Your team’s morale drops because everyone can see the problem. And you’re making desperate sales calls instead of strategic ones.

And it’s not just the day to day. Concentration compresses your valuation.

An agency making £500K profit from 40 clients at a reasonable spread, no single client above 10%, might sell for 6 to 8 times EBITDA. Maybe more if everything else is clean.

Same £500K profit. But one client represents 40% of revenue. 3 to 4 times. Maybe less.

Same profit. Half the exit value. Because the buyer is underwriting the risk that one relationship, one decision, one person leaving could take 40% of the business away.

Four moves to fix concentration in 90 days

You don’t fix this by panicking or firing your biggest client. And definitely not by chasing 20 tiny retainers just to dilute the percentage. You fix it with four deliberate moves. Each one reduces a different dimension of risk.

Move 1: Stabilise the account

The first instinct when you realise you’re concentrated is to reduce dependence on that client. Right direction. But the immediate priority is to stabilise the account so it doesn’t blow up while you’re fixing the problem.

Tighten scope boundaries. If the big account is where most of your scope creep lives (and it usually is), get change control in place. Monitor where you leak time, train your team to spot it, and flag it early.

Add a decision cadence. Monthly review meetings. Not status updates. Decision meetings. What’s working. What needs to change. What’s the plan for next quarter. This turns you from a vendor into a partner. Clients don’t walk away from partners easily.

Document success. Every quarter, produce a one-page summary. What you delivered. The results. The value created. Show commercial value where at all possible. This makes renewals easy and protects you if the marketing director changes and the new one asks “what have these people actually done for us?”

Dilute the influence. If you as the founder are the only person the client talks to, that’s a single point of failure. Introduce a senior team member as the day-to-day contact. You stay at the strategic level. I know that feels risky. Do it anyway. This frees you up to bring on and deliver more high-value work.

Move 2: Fix the commercial shape

If your biggest client is also your biggest commercial risk, the deal terms need to match the scale.

Contract term. A big client on a rolling monthly is a ticking bomb. You need a minimum 6-month term. Ideally 12. Frame it as mutual commitment. “We’re dedicating senior resource to your account. A 12-month term means we can plan properly and invest in understanding your business.” I’ve never had a good client push back on that.

Pricing. Is the big account on the same rate card as everyone else? It shouldn’t be. At a certain scale, the complexity and the account management overhead increase. Price for that. At Kaizen, I had clients who’d been with us for years, still on the same rates from when we were small and needed the work. I never revisited those rates because I was afraid of the conversation. That was a mistake.

Renewal checkpoints. Don’t let a big contract auto-renew without a conversation. Every 6 months, sit down. Review scope, pricing, team allocation, success metrics. This isn’t a negotiation. It’s an alignment meeting. But it gives you the chance to adjust terms as the account evolves.

Notice period. If they can leave without notice, you’re absorbing all the risk. 30 days is reasonable for a significant account.

Move 3: Build a non-founder acquisition motion

This is the big one. Concentration persists for one reason. Only the founder can sell.

New clients come from the founder’s network. The founder’s reputation. The founder’s LinkedIn. So when the founder is busy servicing the big account, pipeline dries up.

And this is where the branding story comes back in. That client who didn’t know we offered branding? That wasn’t a sales failure. It was a communication failure. We were so focused on delivering what they asked for that we never systematically told our existing clients about everything else we could do.

Most agencies only sell about 30% of what they could to each client. You’re sitting on revenue from your existing client base that you’re not capturing because nobody’s telling them.

So the first acquisition motion isn’t outbound. It’s internal.

Create a client/service matrix. Put every client on one axis. Every service on the other. Put a tick where they’re buying from you. The gaps? That’s your pipeline. Those are warm conversations with people who already trust you. That’s the easiest revenue you’ll ever generate.

Then extract yourself from one external sales motion. Referral partnerships. Inbound leads from your website. Pick one. Have your team run it consistently for 90 days. The goal isn’t to replace the big client overnight. It’s to prove that revenue can come from somewhere other than your network.

Move 4: Design capacity so you can absorb churn

This is the defensive move. It’s also the one most people skip.

If losing one client means layoffs, you’re trapped. You can’t negotiate properly. You can’t enforce boundaries. You can’t walk away from bad terms.

Cash buffer. Maintain a minimum of 3 months of operating expenses in reserve. This is the non-negotiable I expect from all of my clients. Because this is the difference between “we lost a client and we need to restructure calmly over 90 days” and “we lost a client and we’re making people redundant next Friday.”

Don’t hire just-in-time for one account. If the big client grows and you hire specifically to service them, those new hires are client-funded, not business-funded. If the client leaves, you’re overstaffed immediately. Use contractors for single-account surges. If you’re still maxed out in month 3, then hire.

Cross-train key roles. If one person is the only one who can service the big account, you’ve got another single point of failure. Make sure at least two people can handle the critical functions. If the knowledge lives in one person’s head, it’s not a system. It’s a liability.

The nuance: not all concentration is created equal

One of our longest clients at Kaizen was a company called Shine. They were with us for all 13 years. From 2009 right through to exit. And they’re still a client today.

Shine started with flyers. Basic print work. And the price of those flyers? Never increased. Not once in 13 years. On paper that looks terrible. A loss-making service you should have dropped years ago.

But the total relationship told a different story. Because of those flyers, Shine gave us project work. Digital work. Events. Print across multiple divisions. Over 13 years, the total value of that relationship was enormous. The flyers were a loss leader. I just didn’t plan them that way.

Shine was never a concentration risk, even though they were a long-term, significant client. The relationship was broad (multiple services), deep (multiple contacts in their business and ours), and contractually sound.

Compare that to a client who represents 30% of your revenue but you only do one thing for them, through one contact, on a rolling monthly. Same revenue dependency. Completely different risk profile.

When you’re assessing concentration, look at three things. Revenue share, yes. But also breadth of services and depth of relationships.

Sometimes the fastest way to reduce concentration isn’t getting new clients. It’s deepening the relationships with the ones you already have.

What to do this week

Two numbers. Your top client’s percentage of revenue. Your top three clients’ percentage of revenue. Write them down.

Then for your top client, answer four questions. What’s the contract term and notice period? Is there a backup relationship owner? When was the last time you presented a success summary? And how many of your services are they actually buying?

That gives you your concentration risk profile and your first moves.

If you want a complete picture of how concentration affects your agency’s valuation, take the free Agency Valuation Assessment. It takes about 10 minutes and walks you through everything.