Why Your Client Concentration Number Is Misleading You

Say a client represents 25% of your agency's revenue. That's a meaningful number, but it isn't the most important one.

Now suppose that same client consumes 35% of your people and 40% of your senior leadership team's time. That's a very different picture of the risk.

Call the first number revenue concentration and the second delivery concentration. Most agency owners track the first. Far fewer have a clear picture of the second. And when delivery concentration runs well ahead of revenue concentration, the agency is more dependent on that client than the P&L suggests.

That's why there's no universal percentage at which a client becomes too large. A client at 25% of revenue can be a healthy relationship, and a client at 15% can create real vulnerability. The difference is what sits underneath the revenue.

So start with a more useful question:

If your largest client put the account in review next month, what would you have to change about the company?

If you'd have a revenue gap you could absorb while replacing the business, that's manageable. If it means reorganizing teams, reducing headcount, or rethinking capabilities, your exposure is larger than any revenue percentage will show you.

1. Measure People, Not Just Revenue

Look at your largest accounts and ask how much of the organization is actually built around each one. How many people spend most of their time on the account? How much senior leadership attention does it require? Have you hired specialists whose skills are mainly useful to that client, and could those people move to other accounts if you needed them to?

The practical exercise is simple: compare each major client's share of revenue with its share of agency resources. If those numbers are far apart, find out why.

2. Put Your Largest Clients and Most Profitable Clients Side by Side

Big clients can create efficiencies, but they also create leverage. As an account becomes more important to the agency, saying no gets harder.

An extra request gets absorbed. A senior person gets added to a meeting. Scope expands without a matching fee increase. Procurement pushes harder on rates. None of those decisions damages the economics of an account by itself. Together, they can.

At least once a year, make two lists: your largest clients by revenue, and your most profitable clients. If the lists look very different, that's worth understanding. A large account should be judged not only by the revenue it generates, but by the organizational capacity required to generate it.

3. Count Relationships, Not Years

Founders often describe a client as secure because “we've had them for ten years.” Tenure matters, but relationship depth matters more.

If a major account depends mainly on one CMO, one procurement executive, or one senior relationship, the revenue is less secure than it looks. People leave. Organizations restructure. Companies merge. New leaders bring in new agencies, and accounts go into review.

For every major account, build relationships with multiple senior people rather than relying on a single sponsor. Then ask:

If our strongest sponsor left tomorrow, who else inside the company would fight to keep us?

The answer tells you more about how durable the account is than the number of years you've had it.

4. Watch What Happens to Your Pipeline

This is the most counterintuitive part of managing a fast-growing client.

When a major account expands, the natural instinct is to put resources behind it, and you should. The mistake is letting the account's growth crowd out investment in new business. That's how concentration compounds:

The client grows.

Leadership attention shifts toward servicing it.

New-business activity slows.

The pipeline weakens.

The client becomes an even larger share of revenue.

And because the agency now depends on it more, even more attention goes toward protecting it.

The cycle feeds itself.

The right response to a rapidly growing client is often to increase new-business investment. Use the cash flow, capabilities, and credibility the large account creates to build your next sources of growth.

The goal isn't to make your biggest client smaller. It's to make the rest of the agency bigger.

The Concentration Check

For each of your largest clients, ask four questions:

People: How much of our organization, especially our senior talent, is dedicated to this account?

Margin: Is this account as profitable as its revenue makes it look?

Relationships: How many meaningful senior relationships protect the business?

Pipeline: Are we still investing in the next sources of growth?

Then run the same exercise across your top three and top five clients. It gives you a far more useful picture of concentration than a single percentage.

Concentration Is a Resilience Issue

None of this means an agency should avoid large clients. A major client can transform an agency. It can fund new capabilities, attract talent, build credibility, and open doors that wouldn't otherwise exist.

Take the growth. But understand what it's doing to the rest of the business. The healthiest response to a growing account isn't to hold it back. It's to keep building the agency around it.

In the end, the question isn't how much revenue your largest client represents. It's how much of your company depends on that revenue. Those are two very different numbers.

Look at your largest client this week. Compare its share of revenue with its share of your people and senior leadership time. If those numbers tell different stories, pay attention to the second one.