One Customer at 40% of Revenue Isn’t a Strength

Quick answer

Customer concentration is the share of revenue coming from your largest accounts. Owners often see a big client as proof the business works. Buyers see a single point of failure, because if that customer leaves after the sale the earnings they paid for disappear. Concentration above roughly 20 percent in one account starts to affect the multiple, and above 30 or 40 percent it can shrink the buyer pool, load the deal with earnouts, or end it outright.

Key takeaways

• Buyers price the risk that revenue does not survive the ownership change.
• Concentration is usually measured on revenue, but concentration of gross profit matters just as much.
• It also applies to suppliers, referral sources, and individual salespeople, not only customers.
• It is fixable, but it takes longer than almost any other value driver, which is why it needs a head start.

Why buyers treat it as risk

Put yourself on the other side of the table. You are borrowing money to buy a business, and the loan payments do not care who your customers are. When 40 percent of the revenue sits with one account, you are not buying a diversified business. You are buying a relationship, and you have no idea whether it will still exist in twelve months.

The concern sharpens when the relationship is personal. If that client works with the company because they trust the owner, and the owner is leaving, the risk is not theoretical. This is where concentration and owner dependence compound each other, and why the two together do more damage than either alone.

A lender does the same arithmetic. If the biggest account walking away would leave the business unable to service the debt, the loan gets harder to place, and a deal that cannot be financed cannot close at that price.

Where the thresholds sit

There is no single legal cutoff, but the bands buyers and lenders work to are consistent enough to plan around.

• Under 10 percent in any one account. Treated as diversified. No concentration discount applied.
• 10 to 20 percent. Buyers ask questions and look for a contract. Typically a modest haircut, in the region of 5 to 10 percent off the multiple. Many institutional buyers hold an internal line around 15 percent.
• 20 to 30 percent. Material. Commonly 15 to 25 percent off the multiple, along with customer interviews during diligence and part of the price moved into a holdback or an earnout tied to that account staying.
• Above 30 percent. Severe. Discounts commonly run 20 to 40 percent against a diversified peer, and a meaningful share of buyers, institutional ones in particular, step away rather than price it.

Two refinements matter. First, look at gross profit as well as revenue, because a large low-margin account may be less critical than it appears, and a smaller high-margin one may be more. Second, look at the top three combined. Three clients at 18 percent each is 54 percent of the business resting on three phone calls.

Lenders draw their own lines, and they matter because a deal that cannot be financed cannot close at the agreed price. Commercial banks frequently write covenants requiring the largest customer to stay below roughly a quarter of revenue, and asset-based lenders often exclude whatever portion of a single customer sits above 15 to 25 percent from the borrowing base entirely.

How to measure it in an afternoon

Most owners have a rough feel for this and are wrong about the detail. The exercise takes an hour and is worth doing before anyone else does it for you.

• Pull last twelve months of revenue by customer and sort descending.
• Calculate each of the top ten as a percentage of total revenue.
• Do the same for gross profit, because the ranking often changes.
• Note which of the top five are under contract, and whether those contracts survive a change of ownership.
• Note which relationships sit with you personally rather than with a named employee.

The output is a single page. That page is one of the first things a serious buyer will ask for, and having it ready signals that you understand your own business.

It is not only customers

The same logic applies anywhere the business depends on a single point.

• Suppliers. One vendor for a critical input, especially without a contract, is a risk a buyer will price.
• Referral sources. If most new work comes from one partner, that partner effectively controls your pipeline.
• Salespeople. Revenue that runs through one person who is not part of the deal is concentration with legs.
• Locations or contracts. A single lease or a single government contract that can be cancelled on a change of ownership.

Each is worth knowing about before a buyer finds it, because the discovery is often more damaging than the fact.

The surprise problem

Buyers can get comfortable with concentration they knew about from the beginning. What they cannot get comfortable with is finding it midway through diligence.

At that point the issue stops being the customer and starts being trust. Once a buyer feels that material facts are surfacing rather than being disclosed, they begin re-testing everything else you have told them, and the deal slows down or reprices.

So if you have concentration, put it on the table early, in your own words, with context. “Yes, this account is 30 percent of revenue. We have been their supplier for nine years, it is under a three-year contract, and here is what our pipeline looks like.” That is a manageable fact. The same fact discovered in week five is a problem.

How to reduce it

This is the value driver with the longest lead time, which is exactly why it belongs on your radar early rather than in the year you plan to sell.

The fastest structural fix is to put the relationship on paper. A multi-year contract with an assignment clause that survives a change of ownership does not reduce the percentage, but it materially reduces the risk attached to it.

The real fix is growth in the rest of the business. Concentration falls fastest when the denominator grows, so adding mid-sized accounts usually works better than trying to shrink the large one. Move the relationship off yourself and onto named account managers, so the client belongs to the company. And be honest about whether the big account is profitable enough to justify the discount it creates at sale.

If you want to see how concentration interacts with the other risk factors, the five value drivers buyers pay for covers the full set, and valuation multiples by industry shows how those factors move you within your industry range.

What it costs in practice

Two identical businesses, each with $500,000 of adjusted earnings. The first spreads revenue across 45 accounts with none above 7 percent. The second has one client at 38 percent, on a rolling handshake, managed personally by the owner.

The first might carry a 4x multiple, for a value near $2 million. The second is more likely to see 2.75x, for around $1.375 million, and a buyer may also want a larger share of that held back in an earnout tied to the big account renewing.

Same earnings. A difference of roughly $625,000, plus worse terms on what remains. That is what a single relationship can be worth at the closing table.

When concentration is less alarming than it looks

Not every large account carries the same weight, and a good advisor will argue the distinction on your behalf.

A long tenure helps. A client of eleven years with no competitive process in between reads very differently from one won last year on price. So does the depth of the relationship: if your business is embedded in their operations, integrated with their systems, or holds a certification that took two years to obtain, switching is expensive for them and the risk is lower than the percentage suggests.

Structural stickiness matters too. Being the sole approved supplier, holding equipment on their site, or serving multiple divisions through separate contacts all reduce the chance that one decision ends the relationship.

None of these make the concentration disappear. They change the story you can tell about it, and the story is what a buyer prices.

The version that worries buyers most

The opposite case is worth naming plainly, because owners often do not see it as concentration at all.

• The client came through a personal friendship, and the friendship is with you.
• There is no contract, or a contract that expired and nobody renewed it.
• The account is up for competitive tender in the next eighteen months.
• Their business is itself concentrated, or in an industry under pressure.
• Margins on the account are thin, so you carry the risk without the reward.

Any two of these together will show up in the price. All five is the profile that makes buyers walk.

Have the answer ready

At some point a buyer will ask what happens if your largest customer leaves. Owners who have not thought about it tend to answer defensively, which reads as though the question landed.

The better answer is specific. Here is what that account contributes in gross profit. Here is the fixed cost we would remove within ninety days. Here is where the business breaks even without them. Here is the pipeline we would redirect toward.

That answer does not make the risk go away, but it demonstrates that you have priced it yourself. Buyers pay more for owners who clearly understand their own business, and the ones who have never run the numbers on their biggest account are telling a buyer something they did not intend to.

Frequently asked questions

What is customer concentration in a business valuation?

It is the share of revenue that comes from your largest customers. Buyers use it to judge how much of the earnings would be at risk if one relationship ended after the sale, and it feeds directly into the multiple applied to your earnings.

How much customer concentration is too much?

There is no fixed cutoff. Under 10 percent in any one account is treated as diversified. Between 10 and 20 percent buyers ask questions and often take a small haircut. Between 20 and 30 percent the discount is material, commonly 15 to 25 percent off the multiple. Above 30 percent, discounts of 20 to 40 percent are common and some buyers step away entirely.

Does a long-term contract fix customer concentration?

It helps considerably. A multi-year contract that survives a change of ownership reduces the risk attached to the concentration, even though the percentage is unchanged. Handshake arrangements with large clients are the most damaging version.

Should I tell a buyer about concentration up front?

Yes. Buyers can price concentration they know about from the start. Concentration discovered during due diligence reads as a disclosure problem, which damages trust across the whole deal and often costs more than the fact itself.

How long does it take to reduce customer concentration?

Usually one to three years, because the reliable route is growing the rest of the business rather than shrinking the large account. That lead time is the main reason to measure it well before you plan to sell.

Find out what concentration is costing you

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This article is educational and not financial, legal, or tax advice. For a number specific to your business, request a certified valuation.