When Your Best Customer Hurts Your Credit

A company I work with had a $7M book of business and wanted a $400K revolving credit line to fund a government contract. Clean books, profitable, three years of consistent growth.

The bank said no. Their top customer was 31% of revenue. The bank's concentration policy maxed at 25%. End of conversation.

The contract went elsewhere.

What lenders actually see

Most commercial banks set a hard ceiling at 20-25% revenue concentration for any single customer before they'll underwrite a revolving credit facility. It's not a guideline. It's a policy. A credit officer doesn't have authority to waive it.

When one customer represents 30% of your revenue, the bank's logic is simple: if that customer pauses orders for 90 days, your debt service coverage collapses. The bank is not wrong.

Private equity buyers apply a similar lens. A business with 30%+ concentration typically sees deal valuations discounted 20-35% from comparable companies without it. Some buyers pass entirely. The customer relationship that felt like proof of quality becomes evidence of fragility.

Concentration risk doesn't change what your business is worth. It changes who can buy it and at what price.

How companies end up here

Concentration rarely happens because founders ignored the risk. It happens because growing with a great customer is exactly what you're supposed to do.

You win a large enterprise account. They want more. You deliver. They expand. Three years later they're 28% of revenue, your team is structured around their needs, and margins look great because of volume they're doing on a preferred basis.

Inbound-heavy growth creates a separate version of the same problem. When you don't invest in outbound, your customer base reflects who found you. In many B2B markets, that means a handful of similar buyers from the same industry or referral network. Five customers in the same vertical can create effective concentration even if no single one breaks the threshold.

The fix takes longer than you want

You can't solve concentration in the two months before you need financing. Building a meaningfully different revenue mix takes 12-24 months, and only through new customer growth, not by losing the concentrated customer.

The math makes this harder than it sounds. If your top customer is 30% of $7M revenue ($2.1M), you need to grow total revenue to $10.5M before they're 20% of the book. That's 50% revenue growth with all of it coming from new accounts.

Start tracking concentration now even if it isn't a current problem. Most companies don't know their number without pulling it specifically. If you're above 20% in any single customer, model what that means for a future financing or sale process.

Before any bank conversation, ask the banker what their concentration policy is. Some lenders exclude government customers from the calculation. Others weigh long-term contracts differently. But that answer needs to come before you're sitting across the table, not after they've already run your file through credit.

The fix is a revenue growth problem disguised as a finance problem. Which means it takes longer than anyone wants to hear.