Which of your customers is actually profitable?

Every figure below is hypothetical. The pattern is not.

Ask any business owner who their biggest customer is and you get an answer immediately. Ask who their most profitable customer is and you get a pause, then a guess, then usually the same name.

It is frequently not the same name.

Two customers

Customer A buys ₦12,000,000 a month from you. Customer B buys ₦3,000,000. On revenue, A is four times the business and nobody would think twice about which one to protect.

Now add the two things that never appear on the same page as revenue — the margin, and when the money actually arrives.

A still earns you ₦150,000 a month more than B. On that basis A wins, and this is where nearly every analysis stops.

The number nobody calculates

A's ₦150,000 advantage is bought with ₦30,000,000 of your cash, sitting outside the business at all times. So ask the question you would ask of any other investment: what return are you getting on that money?

₦480,000 × 12 months = ₦5,760,000 a year
₦5,760,000 ÷ ₦30,000,000 = 19.2% a year

Nineteen percent sounds respectable until you put it beside what money costs. If you borrow at 30% — or if you have an alternative use for cash that returns more than 30%, which in a trading business you almost certainly do — then:

₦30,000,000 × 30% = ₦9,000,000 a year   (what the cash costs)
₦30,000,000 × 19.2% = ₦5,760,000 a year (what A returns)
Difference: −₦3,240,000 a year

Customer A, your largest account, is losing you roughly ₦3.2 million a year. Not making less than you thought. Losing.

Customer B ties up nothing. Every naira B earns is available again within days to buy the next load. B's ₦330,000 a month is not smaller than A's ₦480,000 in any way that matters — it is free, and A's is rented.

Why this stays invisible

Three reasons, and all of them are structural rather than anybody's fault.

Revenue is loud and margin is quiet. Sales figures get celebrated in the group chat. Nobody announces the payment terms.

The cost of tied-up cash never appears as a line item. There is no invoice for it. It shows up as a general feeling of being short of money in a business that is, on paper, profitable — which is the single most common condition in Nigerian trading businesses and the one people most often misdiagnose as a sales problem.

The three inputs live in three different places. Margin is in your costing, if you have one. Payment timing is in your bank statement. Volume is in your invoices. Nobody has ever had cause to put them on one page, so the answer has never been visible to anybody.

The ranking to actually use

Stop ranking customers by revenue. Rank them by annual gross profit divided by the average cash they tie up. One number, comparable across every account, and directly comparable to what money costs you.

To calculate it you need three things per customer, all of which you already generate and most of which you are not keeping:

1. Gross margin on what they buy — not your average margin, theirs. Different customers get different prices, and the ones who negotiated hardest are usually the largest.
2. Average days to pay, measured — from your own records, not from the terms you agreed. Those are different numbers and the gap between them is itself worth knowing.
3. Average balance outstanding — roughly, their monthly purchases multiplied by their days-to-pay divided by thirty.

That is it. Three columns, one division, and a list that will not look like the list in your head.

What to do with the answer

Do not fire Customer A. That is the instinct and it is usually wrong — the volume may be carrying real fixed costs, and a business that sheds 60% of its revenue on a spreadsheet insight tends not to survive the discovery.

Reprice them instead. A's problem is not that they are big; it is that they are big at 4% on 75 days. Any of these fixes it:

• Move them to 30 days at the same margin, and the tied-up cash falls from ₦30m to ₦12m
• Hold the terms and raise the margin enough to cover the financing — see should you sell diesel on credit for how to price that
• Split the difference, which is what usually actually happens in the conversation

And go find more customers like B, who you have almost certainly been under-serving because they are small on the only list you had.

The uncomfortable part

Most owners already suspect which customer this is. What they lack is the arithmetic to say it out loud — to their partner, to their sales person, and most of all to the customer, who will absolutely ask you to justify a repricing.

"Your terms cost us ₦3.2 million a year and here is the calculation" is a negotiating position. "We need to increase prices" is a request for a favour.

Same customer, same meeting, entirely different outcome — and the only difference is that somebody did the sum.