THE CLIENT CONCENTRATION PROBLEM: WHAT TO DO WHEN ONE ACCOUNT IS TOO MUCH OF YOUR REVENUE
If you've ever done the math on what happens to your agency if your biggest client leaves—and then quietly closed that spreadsheet because you didn't like the answer—you're not alone. Some version of "what happens if this one account leaves" comes up in almost every client conversation I have, regardless of the agency's size or specialty. It's one of the most universal fears in this business, and one of the least talked about.
Quick answer: if one client makes up more than roughly 20–30% of your revenue, you have real concentration risk—not because that client will necessarily leave, but because your whole business's financial health is now tied to one relationship you don't fully control. The fix isn't firing your biggest client. It's building the rest of the business so that losing them wouldn't be a crisis.
WHY THIS IS SCARIER THAN IT LOOKS ON YOUR P&L
Client concentration doesn't show up as a problem on a normal P&L—it shows up as a great year. Revenue's up, the team's busy, everyone's happy. The risk is invisible until the moment it isn't: a new marketing VP who wants to "review vendor relationships," a reorganization on their end, a budget cut that has nothing to do with your work quality.
You can't control any of that.
What you can control is how much of your business depends on it not happening.
A ROUGH RULE OF THUMB
There's no single "safe" number, but a common guideline: once one client crosses roughly 20–30% of total revenue, it's worth treating as a strategic risk, not just a great account. Some advisors use an even tighter threshold for younger agencies with thinner cash reserves. The exact line matters less than having one—most founders we work with have never actually calculated their own number until we ask.
WHAT TO DO ABOUT IT
Calculate it first. Take that client's trailing-twelve-month revenue divided by total revenue. Most founders are surprised by the number either way—sometimes it's worse than they feared, sometimes it's more manageable than the anxiety suggested.
Don't shrink the big client—grow around them. The instinctive move is to worry about the big account. The more useful move is usually business development on everything else, so the percentage drops because the denominator grew, not because the relationship did.
Diversify the relationship, not just the roster. Multiple points of contact within that client's organization reduce your exposure to a single champion leaving. A scope that touches several of their departments or budgets is more durable than one project tied to one stakeholder.
Build the cash reserve as if it will happen. Even if you never plan to lose the account, run the numbers on what three to six months of reduced revenue would require, and know where that cushion would come from. This is less about pessimism and more about being able to make calm decisions instead of panicked ones if the day ever comes.
Watch the trend, not just the snapshot. A big client at 25% of revenue in a growing, diversifying business is a different risk than the same 25% in a business that's flat everywhere else. Track the percentage quarter over quarter, not just once.
THE UPSIDE NOBODY MENTIONS
A concentrated client relationship is often also your most profitable, most efficient one— less pitching, less onboarding overhead, deep institutional knowledge on both sides. The goal isn't to resent that client or treat them as a liability. It's to make sure their departure, if it ever happens, is a hard year instead of an existential one.
FAQ
What percentage of revenue from one client is too risky? There's no universal number, but many advisors start paying close attention once a single client crosses 20–30% of total revenue. Younger agencies with less cash cushion should treat even lower percentages as worth watching.
Should I turn down more work from my biggest client to reduce risk? Rarely the right move. It's usually more effective to grow the rest of your client base so the percentage naturally comes down, rather than limiting your best relationship.
How do I know my real client concentration number? Divide that client's trailing-twelve-month revenue by your total trailing-twelve-month revenue. If you're tracking new vs. existing revenue separately, this calculation gets much easier—more on that in New Business vs. Existing Revenue.
What's the actual risk if I do nothing? Not that the client will definitely leave—it's that your agency has no plan if they do. Cash reserves, a diversification timeline, and multiple stakeholder relationships turn an unpredictable risk into a manageable one.
If you've never actually run this number for your own agency, it is one of the main things we uncover in our Growth Blueprint.
About the Author: Meredith Fennessy Witts
Founder & Strategic Growth Advisor at Le Chéile and Co-Host of
With a background in financial and operational consulting and a successful track record of founding and scaling her own agency, Meredith brings deep expertise in strategic growth for indie creative and digital agencies.
Her company, Le Chéile, helps agencies scaling toward and beyond 5M+ in revenue to rightsize teams and payroll, increase founder pay, scale offers and packages and more. She helps clients to achieve their goals while clarifying their business strategy and finances.
She is a trusted authority on building mindful, profitable businesses—especially for underserved founders in the women, LGBTQ+, and BIPOC communities.
Beyond Le Chéile, Meredith co-hosts , a podcast for creative agency founders, and its companion . She also runs , a community for fractionals and consultants in the agency space.
View full bio and connect with Meredith on or listen to Meredith’s podcast, .
