If a single client represents more than 15% of your revenue and their invoices are overdue, you have a concentration risk that no amount of polite emails will resolve. The larger the client, the more leverage they believe they have — and they're right, as long as you behave as if losing them would be catastrophic. The solution isn't to chase harder or wait longer. It's to change the dynamic.
You know exactly which account this is. The one your CFO mentions in every meeting. The one where everyone agrees "we should really follow up" and nobody does — because the implicit calculation is that chasing might damage the relationship, and the relationship is worth more than the invoice. But that calculation has a flaw: the client already damaged the relationship by not paying you. Here's how to recover the money without losing the account, and how to prevent this from happening again.
Why do large clients pay late?
The uncomfortable truth: because they can. Large companies use supplier payment terms as a free credit facility. Your invoice sits in a payment queue alongside hundreds of others, prioritised by who creates consequences for non-payment and who doesn't.
A Fortune 500 client paying you 120 days late isn't having cash flow problems. They're managing their own working capital by borrowing yours. The procurement team negotiated 30-day terms knowing that accounts payable would stretch it to 90-120, and that you — their smaller supplier — wouldn't push back.
This is rational behaviour from their perspective. The question is whether you accept it as inevitable or change the cost-benefit calculation.
How do I collect from a large client without losing them?
The approach must be formal without being hostile, escalating without being aggressive.
Step 1: Formalise the communication. Move from your account manager's casual emails to your finance department's formal correspondence. This signals that the matter has moved from relationship management to financial process. The tone changes from "just checking in" to "per our agreed terms, invoice #X is now Y days overdue."
Step 2: Reference your contractual terms. Late payment interest, compensation for recovery costs (€40 minimum under EU Late Payment Directive per invoice), and any specific remedies in your contract. You're not threatening — you're informing them of a contractual position they agreed to.
Step 3: Introduce a professional third party. A collection agency entering the conversation changes the dynamic fundamentally. It signals that you have a process and that this invoice has now entered it. For large B2B clients, this is rarely about the amount — it's about the signal that the informal credit arrangement has ended.
Step 4: Protect the relationship through professionalism. The best collection agencies specialise in exactly this: recovering money from important clients without burning the bridge. The debtor often respects the creditor more afterward — because you demonstrated that your business has standards.
What if they threaten to take their business elsewhere?
This is the leverage play, and it works on most suppliers. The correct response is a calm assessment: what is the actual profit margin on this account once you factor in the cost of financing their late payments? A client who represents 20% of your revenue but pays 120 days late while consuming disproportionate support resources may be less profitable than they appear.
Some companies have discovered that losing a large, chronically late-paying client actually improved their cash flow and profitability. Not always — but more often than the fear suggests.
How do I prevent concentration risk?
The collection conversation is the immediate problem. The structural fix is longer-term.
Monitor the percentage of revenue any single client represents. When it exceeds 15%, treat it as a risk metric — the same way you'd monitor any other financial exposure. Diversify your client base deliberately. And implement payment terms that include consequences for late payment from day one — including large clients. The companies that enforce payment terms consistently get paid faster than those that make exceptions for their biggest accounts.
What is client concentration risk?
Client concentration risk is the financial exposure created when a disproportionate share of your revenue depends on one or a small number of clients. When that client pays late, disputes an invoice, or leaves entirely, the impact is existential rather than manageable. Best practice: no single client should represent more than 10-15% of total revenue. Above that threshold, their payment behaviour becomes a cash flow risk that warrants active management.
The invoice you're thinking about represents two problems: the money you're owed today, and the structural risk you'll face again next quarter. We can help with both.
Contact us for a free review. Confidential, diplomatic, and designed to preserve the relationship.