Your Biggest Client Is 35% of Revenue. Now What?

Your largest client just renewed. Everybody is relieved.

You are also aware that one email from that account could change your entire year.

When a client represents 35% of revenue, the useful question is what would happen if the work shrank or stopped. Answer that before fear talks you into selling anything to anyone.

Start with the dollars that would actually disappear

Use a consistent revenue basis. If your agency passes through media spend or other large third-party costs, comparing gross billings can hide the business you actually keep. Work with your finance person to use the measure that represents your agency's revenue accurately.

Then look at what the account contributes after the costs directly associated with serving it, and which costs would remain if it left.

Here's a simplified monthly scenario. These numbers are illustrative, not benchmarks:

The $70,000 account contributes $45,000 after its immediately avoidable costs. Losing it changes the operating result by that amount.

Your real situation will have timing differences. A contractor commitment might last another month. Employees may move to other accounts. Receivables may arrive after the work stops. Model those separately rather than assuming revenue and cost move together on the same day.

Test a reduction too

A client doesn't have to leave to create a problem. They can halve the scope while your staffing obligations barely change.

Model the account continuing, shrinking, and leaving. For each, identify the likely notice period, cash collection timing, costs you could change, and work you could redeploy people into.

Include your own normal compensation in the cost picture. An agency that survives because you stop paying yourself has transferred the problem to your household.

The cash flow playbook addresses billing discipline. This exercise addresses what happens when the underlying work changes. You need both views.

Protect the relationship without becoming terrified of it

Concentration can make owners weird. They stop challenging bad ideas, absorb extra scope, and agree to terms they would reject from any other client.

That can make an important account less profitable while leaving the dependency intact.

Instead, examine the account like a business relationship. Who understands your contribution? Who approves the budget? What are they trying to accomplish next? Where have their priorities changed?

Build relationships beyond one friendly contact. Keep a current view of results, concerns, and next decisions. Raise problems early. Discuss new requests as changes to scope, not loyalty tests you must pass for free.

The account growth playbook helps you understand the business behind the work. Growth in the account may be worthwhile, but recognize when it increases your exposure too.

Don't pick a prettier percentage and call it a plan

Suppose that $70,000 account stays flat and you decide you want it to represent 25% of revenue.

Total monthly revenue would need to reach $280,000 ($70,000 divided by 0.25). That means adding $80,000 beyond the current $200,000.

The 25% figure is an example, not a universal safe line. The calculation shows the size of the assignment. It doesn't tell you whether your agency can profitably deliver the additional work or how quickly it can win it.

Also check what sits behind the other clients. Ten accounts in the same fragile category may share a risk. Several logos owned by one parent company may share a budget decision.

Choose a direction you can support with actual sales capacity, delivery capacity, and economics. Review concentration alongside those factors rather than chasing a percentage in isolation.

Build the response while you still have choices

Write down the signals that would make you revisit the plan: budget pressure, reduced scope, leadership changes, delayed payments, or a known renewal decision.

Assign responsibility for watching them. Agree on what you would do if they occur, including which spending and hiring decisions need another look.

Keep pursuing suitable clients before the large account becomes uncertain. Preserve the standards that made your agency worth hiring in the first place. Panic acquisition has a way of filling the roster with work you'll regret winning.

Bring your own numbers to a WTF Call if you need help thinking through the growth and operating decisions together.

You can value a great client and still build a business that survives their departure. That is a much better relationship than gratitude with a hostage clause.

Go deeper: Concentration risk is a cash problem before it is a revenue problem. Here is how to protect the cash. The Agency Cash Flow Playbook