Customer Revenue Concentration: The Median Contractor Gets 31.0% From One Client

The Median Contractor Is Already in the Danger Zone

The median contractor gets 31.0% of all revenue from a single customer.

That number comes from the Level Index: 959 contractors with at least $100K in annual revenue, measured as the share of total revenue from the single largest customer. The companies span HVAC, plumbing, electrical, mechanical, and refrigeration, but trade subsets are not separately measured, so read 31.0% as a cross-trade figure, not an HVAC or plumbing benchmark. It is a sample of companies in the benchmarking dataset, not a survey and not a census of all contractors. The measurement period is not stated in the metric definition used here.

Important context: The commercial versus residential mix of the 959 companies is not separately reported, so this page cannot say how much of the 31.0% median comes from commercial work. The mechanism still matters when you read your own number. A commercial contractor serving GCs, property management firms, and facility owners can have a few large relationships that drive most revenue. A residential contractor serving many individual homeowners usually has a much smaller top-customer share. If you're residential-heavy and your top customer is 31%+, ask why one account is that large. If you're commercial-heavy, compare against other commercial firms where you can, not only against this cross-trade median.

That said, 31.0% still matters: PE buyers, lenders, and bonding companies commonly ask about customer concentration, and the median company in this sample sits above the roughly 20-25% range where many underwriters start asking questions. Exact thresholds depend on the lender, surety, or buyer.

The Full Distribution

Top-5 customer share and an average are not part of the verified metric used here, so they are not shown. Calculate your own top 5 and top 10 with Step 1 below.

The spread is wide. A quarter of companies get 54.6% or more of revenue from one customer, and at P90 the top customer is 82.4% of revenue. At that level the exposure to one account is large, but concentration does not establish contractual captivity.

Even the median is alarming. When your largest customer represents nearly a third of revenue, every decision they make, to switch vendors, bring work in-house, reduce scope, or delay payment, directly threatens the viability of your business.

We've written about customer profitability analysis and why your biggest client by revenue may not be your most profitable. Concentration makes that problem worse: when an unprofitable customer is also a third of your revenue, you can't reprice them without risking the whole business.

What PE Buyers See

I spent two years in private equity evaluating contractor acquisitions. Customer concentration was the first thing we flagged, before margins, before EBITDA quality, before financial infrastructure. Here's a common lower-middle-market pattern, shown as an illustrative planning frame rather than a rule every buyer follows:

Valuation-discount ranges are illustrative planning assumptions for lower-middle-market deals, not measured medians and not from a published survey. Actual discounts depend on contract terms, customer tenure, margin by customer, and the buyer. Use them to stress-test your own number, not to price a deal.

Many lenders and underwriters scrutinize concentration above roughly 20-25%. This page has not verified a specific SBA SOP provision that sets a fixed 25% customer-concentration rule, so ask your lender for the policy it actually applies. The median company in this sample, at 31.0%, is above that range. For commercial contractors this is common and not necessarily disqualifying, but expect diligence questions in a loan or transaction process. The P75, at 54.6%, is in the range where the illustrative discounts in the table get significant.

I've covered the full PE evaluation framework in a separate post, but here's the valuation math on concentration specifically, using the illustrative table above. Assume a fictional, well-diversified contractor would get 5.5x EBITDA. The same business with 35% concentration, at the table's up to 10% discount, would be about 4.95x. Above 50%, at a 25-35% discount, it would be about 3.6x to 4.1x. A drop all the way to 3x at 35% concentration can happen in a specific deal, but it would reflect other issues too, such as no contract with that customer, thin margin on the account, or weak financials. These are EBITDA multiples. SDE multiples on smaller owner-operated businesses use a different earnings basis and are not interchangeable.

For a fictional $10M contractor running 15% EBITDA margins ($1.5M EBITDA), 5.5x is $8.25M of enterprise value and 4.95x is about $7.43M, a gap of about $825K. At 3.6x the value would be $5.4M, a gap of about $2.85M. Either gap is large enough to justify working on concentration before a sale process.

This is also why revenue mix matters so much for valuation. Recurring agreements do not guarantee diversification: one property-management portfolio can support many agreements yet remain one customer exposure. A book with dozens or hundreds of independent accounts differs from an install book with 3-5 large buyers, but this page does not measure a service-versus-install concentration difference. Inspect the actual customer groups, contract terms and contribution before making the valuation argument.

The Lending Problem

PE isn't the only place concentration hurts. Many lenders, including some SBA lenders, ask more questions when a single customer is more than roughly 20-25% of revenue. The specific threshold and response come from the lender's credit policy, so get it in writing.

When concentration is high, ask the lender whether any of these apply to your file:

• A larger down payment or equity injection
• A higher rate or fees
• A lower advance rate or loan-to-value
• Additional collateral, personal guarantees, or a copy of the customer contract

Because the median is 31.0%, at least half of the 959 companies in this sample have a top customer above 25%. Whether any one of them would get tougher terms depends on the lender, the contract with that customer, and the rest of the file. If you're financing equipment, acquiring another contractor, or funding a facility expansion, check whether concentration is affecting your terms before you sign.

Bonding companies often look at the same risk. High concentration can mean higher risk of revenue disruption, which can mean tighter bond lines. For commercial contractors who need bonding capacity to bid work, concentration directly limits your growth ceiling.

The Revenue Cliff Scenario

Forget valuations and lending for a moment. The operational risk is just as severe.

If a contractor at the sample median lost all future work from that top customer, 31.0% of its historical annual revenue would be exposed. Contracted backlog, collections on completed work and replacement sales determine the timing. For a $5M contractor, that's $1.55M of revenue gone. The overhead doesn't shrink proportionally. You still have the trucks, the office, the dispatcher, the insurance. Fixed costs don't flex with a revenue cliff.

At P90, losing the top customer means losing 82.4% of revenue. That is a severe exposure. Whether it forces closure depends on contribution, cash reserves, variable costs and replacement work; revenue share alone cannot answer that.

And it happens. Customers get acquired. Facility managers change. National accounts consolidate vendors. Property management companies switch to in-house maintenance. The customer doesn't need to be unhappy with you. They just need to change strategy.

Revenue lost is not the same as profit lost, so run the cliff on contribution. Fictional example: the $5M contractor loses the $1.55M customer, and that work carried a 40% gross margin after direct labor and materials. Direct costs on that work can flex down. But the $620K of annual gross profit ($51.7K per month) that was covering trucks, office, and insurance is gone. Divide your cash plus available credit by that monthly gap to see how many months you have to replace the work or cut overhead. This page has no measured data on which concentration level predicts survival, so use your own runway number, not a rule of thumb.

The SA Power Law Makes It Worse

The service agreement analysis points to why concentration is so hard to fix. That post reports that 1.4% of service agreements generate roughly 50% of SA revenue, with the largest contracts averaging $520K per agreement. Those figures are not part of the verified metric set used on this page, so check the linked post for its sample and period before citing them. The mechanism holds either way: if a few large agreements sit with a few enterprise customers, SA growth can deepen concentration.

That creates a structural trap. Check whether your biggest SA belongs to your most concentrated customer; the two rankings need not match. Growing SA revenue means landing more of those large enterprise agreements. But each new large SA deepens concentration unless you're simultaneously growing the base of smaller accounts. Most contractors default to chasing the big contracts because the unit economics are better, and their concentration ratio creeps up year over year without anyone noticing.

How to Fix It

Customer concentration doesn't fix overnight. But the trajectory matters more than the current number, especially to PE buyers and lenders.

1. Know your number. Pull trailing 12-month revenue by customer. Calculate top 1, top 5, and top 10 as a percentage of total. If your top customer is above 20%, you have work to do.

2. Grow the denominator. The fastest path from 35% to 20% isn't dropping your biggest customer, it's growing revenue from other accounts. Account penetration and service agreement expansion with your next-tier customers shift the ratio without losing a dollar.

3. Diversify the pipeline. If your quote conversion rate is healthy but all your quotes come from the same 5 customers, conversion rate doesn't help. Track quote volume by customer to ensure new business development isn't just deepening existing concentration.

4. Track it quarterly. Add customer concentration to your weekly or monthly KPI dashboard. If the trend is moving in the wrong direction, catch it before it becomes a valuation haircut.

5. Mirror the analysis on the vendor side. Revenue concentration and vendor spend concentration are two sides of the same coin. The linked vendor analysis reports a median of 33.1% of spend going to a single vendor; that figure comes from a separate analysis whose sample is not defined on this page. Dual concentration, one customer for revenue AND one supplier for materials, compounds the risk.

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The Bottom Line

The median contractor gets 31.0% of revenue from a single customer. That is above the roughly 20-25% range where many lenders start asking questions. In the illustrative discount table above, 25-35% concentration carries up to a 10% discount, with steeper discounts above that.

If you're building toward an exit, concentration can cost real enterprise value. In the fictional example above it costs about $825K on $1.5M of EBITDA at 35% concentration, and more if the customer has no contract or thin margin. If you're not planning to sell, it could cost you the business if that one customer walks.

The fix takes time, but starts with knowing the number.

Q: How does Level help with customer concentration risk? A: Concentration work in an engagement can include several pieces:

• A view of top 1, top 5, and top 10 customers as a percentage of trailing 12-month revenue, tracked quarterly.
• A revenue cliff model built on contribution rather than revenue.
• A diversification plan targeting specific accounts for growth.

If you're preparing for a PE process, the goal is to show buyers the trend and the plan. How far the number moves depends on your accounts and timeline.

Q: What's a safe customer concentration level? A: Below 10% from your top customer is ideal and is unlikely to raise concentration flags. Below 20% is manageable with the right story. Above roughly 20-25%, many lenders ask more questions; confirm your lender's actual policy. Above 35% is where the illustrative discounts in the table above get steep (15-20%+). For commercial contractors with large GC/property management relationships, 25-35% concentration is common, it's a diligence conversation, not an automatic disqualifier. The median contractor at 31.0% has work to do, but 12-24 months can be an illustrative planning horizon, not a measured time-to-improvement. Model the amount of independent revenue needed and the sales capacity to win it.

Q: How do I reduce concentration without losing my biggest customer? A: You don't need to. The math works by growing the denominator, increasing revenue from other customers while maintaining the top account. Cross-selling into existing accounts, expanding service agreement coverage to new properties, and building pipeline with new customers all shift the ratio. A fictional $5M contractor going from one customer at $1.55M (31.0%) to total revenue of $7M with that customer still at $1.55M brings concentration down to 22.1%, without losing a dollar from the relationship.