Customer concentration risk in industrial M&A
Customer concentration is the single most common reason a well-run industrial SME gets repriced late in a deal. It is also one of the few diligence findings a seller can genuinely fix — if the work starts early enough to show in audited numbers.
The 2026 market convention is clear: below 15% of revenue from one client, buyers ignore concentration; above 25%, contract manufacturers typically absorb a 1.0x EBITDA multiple discount; above 30–40%, a large share of buyers walk away rather than negotiate. Diversification is not a growth story — it is a valuation defence.
Why does one large customer cost a full turn of EBITDA?
Because a buyer is not buying last year's profit, they are buying its durability. A client at 30% of revenue holds an option to destroy roughly a third of the acquired earnings, and that option costs nothing to exercise. Lenders see the same thing: debt capacity falls, the equity cheque rises, and the price the buyer can pay falls with it.
The thresholds used across lower-middle-market industrial deals in 2026, as summarised by advisors including FOCUS Investment Banking:
| Top-customer share of revenue | Typical buyer treatment |
|---|---|
| Under 15% | Treated as diversified. No adjustment. |
| 15–25% | Acknowledged in diligence; rarely repriced. |
| Over 25% (contract manufacturing) | Roughly 1.0x multiple discount. |
| Top-3 customers over 40% | Material discounting; structure shifts to earn-out and escrow. |
| Over 30% single customer | A meaningful share of buyers decline outright. |
Two nuances matter more than the headline percentage. First, contract quality: a rolling annual PO with 30-day termination is not the same asset as a three-year nominated-supplier agreement with a qualified tooling spec. Second, switching cost: a client that would need six months and a new homologation cycle to replace you is structurally stickier than one who re-tenders on price every season.
How do buyers actually test it in diligence?
Concentration analysis is a standard workstream inside a quality of earnings review. Expect the buyer's team to ask for:
- Revenue and gross margin by customer for 3–5 years — margin concentration is often worse than revenue concentration.
- Customer cohort retention: which of your top 10 clients five years ago are still in the top 10 today.
- End-customer visibility: if you sell to a converter, who is the brand behind it, and is the relationship yours or theirs?
- Purchase orders, framework agreements, quality approvals, and any change-of-control clause.
- Post-signing customer reference calls — usually the last condition before funds flow.
The change-of-control clause is the one that quietly breaks deals. If a top client can terminate on a change of ownership, the buyer will insist on pre-closing consent, which forces you to disclose the transaction to the exact counterparty with the most leverage over its price.
Can a multi-vertical platform genuinely fix concentration?
It can, but only if the verticals are commercially independent rather than cosmetically different. A buyer separates real diversification from apparent diversification with three questions:
- Do the verticals share a demand cycle? Footwear uppers and leather goods for the same fashion calendar are one exposure wearing two labels. Marine interiors, premium bedding and hospitality packaging run on different capex cycles and different buyer types — that is genuine.
- Do they share a customer? Two divisions selling to the same group is one customer with two purchase orders.
- Do they share the asset base? The best answer is yes: one tannery, one finishing line, one compliance framework, several end markets. That is operating leverage without duplicated fixed cost.
This is the structural argument behind a platform model rather than a mono-product supplier: the same hides, the same LWG Gold–certified process and the same technical team feed footwear, leather goods, marine, bedding and hospitality lines, each with its own demand driver. We covered the thesis in multi-vertical manufacturing platforms, and the counterpart from the buyer's side in why strategic buyers acquire their material suppliers.
What can a seller do in the 18 months before a process?
- Move the mix, not just the pitch. Two years of declining top-customer share is evidence; a slide about a new vertical is not.
- Convert POs into agreements. Even a 12-month framework with a notice period reduces the perceived option value of walking away.
- Document the switching cost. Homologations, tooling, colour recipes archived by batch, audit approvals — all of it is contractual gravity you already own but rarely write down.
- Diversify geographically as well as by customer. An export base across several countries dampens single-market risk, which buyers price separately — a recurring theme in cross-border deals for Spanish industrial SMEs.
- Track margin concentration explicitly. If your largest customer is 22% of revenue but 38% of gross margin, expect the buyer to use the second number.
Certification and traceability work in the same direction: a tannery with LWG Gold status and EUDR-ready documentation is qualifiable by a wider set of brands, which is exactly what makes concentration reducible in the first place.
Frequently asked questions
Is customer concentration always penalised?
No. Concentration inside a long-term, contractually protected, high-switching-cost relationship can read as a moat. What buyers penalise is concentration that is both large and terminable at will.
Does the discount apply to revenue or to the EBITDA multiple?
To the multiple, and therefore to enterprise value. A business at 6.0x EBITDA with a 28% top client is frequently modelled at 5.0x, before any structural adjustment.
Can deal structure solve it instead of price?
Partly. Earn-outs tied to retention of the named account, indemnity escrows and reverse-termination protections are common. Structure moves risk across time; it does not remove it, and sellers should expect a lower certain-cash component.
How is concentration measured — by revenue or by group?
By ultimate parent. Three subsidiaries of the same group count as one customer, and buyers will consolidate them even if your ERP does not.
The open board. Manufacturers, distributors and specialist workshops discuss capacity, subcontracting and joint programmes in the Partners & factories category of the TL San Martín Business Board — a free, open B2B board for the leather and footwear industry. Posting a partnership or capacity brief there is often the fastest first step toward the commercial diversification described above.
TL San Martín — a third-generation tannery in Elda, Spain, tanning since 1995, LWG Gold certified, solar-powered and building AI-assisted sourcing tools — maintains open conversations with partners and investors who share its industrial vision. Confidential contact: jorge@tlsanmartin.com.