A single customer above 20% of revenue raises questions in every sale process; above 40%, buyers cut the multiple hard, typically by one to two turns of EBITDA, or restructure the price around earn-outs and holdbacks. Buyers are not pricing your last twelve months; they are pricing the odds those earnings survive a change of ownership. A customer or channel that can remove a third of your profit with one email is the biggest single threat to those odds, which is why concentration is the first thing diligence tests.
How much customer concentration is too much?
There is no regulator-set threshold, but the lower mid-market has settled on consistent rules of thumb. Below 10% for your largest customer, nobody asks. Between 10% and 20%, buyers note it and move on. Above 20%, you will be asked for the full relationship history: contract terms, tenure, pricing changes over time, who owns the relationship, and what happens on a change of control. Above 40%, the conversation shifts from price to structure, the buyer no longer believes a headline multiple is the right way to pay for earnings that one procurement decision could halve.
Concentration compounds with other weaknesses. A 30% customer on rolling 60-day purchase orders, held together by a relationship the founder personally owns, is a materially worse position than a 30% customer on a three-year contract managed by a sales team. Buyers read the whole picture: percentage, contract, tenure, and whether the relationship walks out the door with you.
Why does diligence probe concentration first?
Because it is the fastest way a good acquisition becomes a bad one. Most diligence findings, a soft add-back, a messy stock count, move the price by percentage points. Losing a 40% customer in month six moves it by half. So diligence starts there: revenue by customer for the last three years, churn and expansion within the top ten, contract review for termination and change-of-control clauses, and quiet reference checks where possible. If you are preparing to run a sale process, assume the buyer will know your customer table better than your sales director does, and build the file before they ask.
In our deals, concentration surfaced late kills more processes than concentration disclosed early. A known risk can be priced and structured; a discovered one destroys trust in everything else you have said.
What does concentration actually cost at exit?
Typical lower-mid-market EBITDA multiples run 3.5x–9x for consumer brands and services, 3.5x–7.5x for agencies, 3.5x–7x for distribution, and 6x–15x for software. Concentration decides where in the band you land, and whether you get the band at all:
- Largest customer under 10%. No discount. You compete for the top of your band on growth and margin.
- 10%–20%. Noted, not priced. Expect questions rather than a haircut, provided contracts and tenure hold up.
- 20%–40%. Typically 0.5x–1.5x off the multiple, or a slice of the price deferred against the customer staying. A services business that would merit 6x can transact at 4.5x–5x here.
- Over 40%. One to two turns off, plus structure: earn-outs tied to the account's revenue, holdbacks, or the buyer walking. Some institutional buyers will not look past 40% at any price.
- Channel concentration of 70%+ through one platform. Priced like a single dominant customer. An Amazon-only brand aiming at 7x will usually be negotiated toward 4x–5x, or toward an SDE-based price if earnings sit under roughly $500k, where buyers typically pay 1.8x–4.2x.
What about channel concentration, the Amazon-only brand?
Everything above applies to channels. A brand doing 85% of revenue through Amazon has one customer in every way that matters: one counterparty sets the fees, controls the traffic, owns the customer data, and can suspend the account without anyone you can phone. Buyers price this exactly as they price a dominant customer, discount plus structure. The same holds for a wholesale brand living inside one national retailer, or an agency whose pipeline is one referral partner. If Amazon is your reality, the fix is not leaving the platform; it is proof that revenue exists off it, a DTC site with repeat purchase, retail or international listings, an email list you own. We cover the full playbook in how to sell an ecommerce business.
How do you diversify without stalling growth?
The mistake owners make is treating diversification as an instruction to starve the anchor account. That trades a valuation problem for a growth problem. The three paths that work run alongside the anchor, not instead of it:
- Clone the anchor. Your biggest customer is proof you can serve businesses like it. Build a named list of the 20–50 closest lookalikes, same vertical, same buying process, and sell the documented result. Adding two accounts at a third of the anchor's size takes 45% concentration to around 30% without losing any existing revenue.
- Open a second channel. For product businesses: DTC alongside Amazon, retail alongside DTC, international marketplaces alongside domestic. The second channel does not need to match the first in size, buyers reward the proven existence of an alternative, because it converts an existential risk into a commercial one.
- Contract and de-risk what you cannot yet diversify. Move the anchor from purchase orders to a multi-year agreement, spread the relationship across your team rather than yourself, and add recurring revenue around it. A 35% customer on a three-year contract with 90-day notice is priced very differently from the same customer on a handshake.
Sequenced properly this is an 18–24 month project, which is why concentration is the first thing we tackle in ongoing advisory work with owners planning to exit inside three years. Every point of concentration you remove is bought back at your exit multiple.
What to do next
Pull your revenue by customer for the last three years and calculate your top-one and top-five percentages, that number sets your negotiating position more than your growth rate does. Then run the business through our free 10-question indicative valuation to see what concentration is currently costing you, and what fixing it is worth.
What is your business actually worth?
Run your numbers through our free valuation tool. Ten questions, an indicative range built on real transaction multiples, and the exact build-up behind it.
Get your free valuation ↗Frequently asked questions
What percentage of revenue from one customer is too much?
Under 10% is a non-issue. Between 10% and 20%, buyers note it and move on. Above 20% of revenue from one customer, expect detailed diligence on the contract, tenure and relationship. Above 40%, most buyers cut the multiple by one to two turns of EBITDA or restructure the deal around earn-outs, and some institutional buyers will not proceed at all.
How does customer concentration affect the value of my business?
It moves both price and structure. In the lower mid-market, a largest customer at 20–40% of revenue typically costs 0.5x–1.5x of EBITDA off the multiple; above 40% it costs one to two turns, plus deferred consideration tied to that customer staying. A services business that would merit 6x with a diversified base can transact at 4.5x–5x with heavy concentration.
Is it risky to sell a business that only sells on Amazon?
Buyers treat 70%+ of revenue through one platform like a single dominant customer, because Amazon controls fees, traffic, customer data and account suspension. Expect a discounted multiple, often 4x–5x where a diversified brand would command 6x–7x, plus earn-out structure. Proving even 15–20% of revenue off-platform through DTC or retail materially improves the price.
How do I reduce customer concentration without losing revenue?
Grow around the anchor rather than shrinking it. Three paths work: win lookalike customers in the same vertical using the anchor as proof, open a second sales channel, and lock the anchor into a multi-year contract while you build. Adding two accounts at a third of the anchor's size takes 45% concentration to roughly 30% with no lost revenue. Plan on 18–24 months.
Will a buyer still buy my business if one customer is 50% of revenue?
Usually yes, but on different terms. Expect a lower headline multiple, a meaningful earn-out or holdback tied to that customer's retention, and heavy diligence on termination and change-of-control clauses. A 50% customer on a three-year agreement managed by a sales team is far more sellable than the same customer on rolling purchase orders held personally by the founder.