Margins shrank while sales grew: how to find out why

Trace a falling gross margin back to the product, channel or discount that caused it rather than cutting overheads and hoping the problem goes away.

Growth that earns less than the year before it

Revenue is up. The team is busier than it has ever been. The annual accounts arrive and gross margin is several points lower than last year so the extra turnover converted into very little extra profit. The usual reaction is to assume costs have crept up everywhere and to start trimming overheads.

That reaction almost always treats the wrong patient. A gross margin decline has a specific cause and it is nearly always traceable to a small number of products, channels or customers. Growth itself is often the mechanism. The new volume arrived through whichever route was easiest to grow and the easiest route is usually the cheapest one.

What the investigation costs and what it will not do

This exercise diagnoses and does not fix. At the end you will know which line is bleeding and you will still have to decide whether to raise a price, drop a product or exit a channel. Those decisions carry consequences the analysis cannot make for you.

The cost is two or three days of someone's attention or a comparable block of your accountant's time. There is no tool purchase. What you must supply is item level sales data for two comparable periods and a cost per unit or cost per job that you actually believe. Where that cost data does not exist the investigation stalls there and building it becomes the first task.

Who should skip this

Skip it if the movement is small and the period is short. Gross margin on a single quarter moves for reasons as ordinary as one large order delivered in week twelve. Compare at least four quarters before concluding anything.

Skip it if you sell one product through one channel. In that case there is no mix to analyse and the answer is either your input price or your selling price. Two supplier conversations settle it faster than any spreadsheet and paying for an analysis of a single variable wastes money.

Skip it too if you cannot separate direct costs from overheads in your ledger. Any margin figure drawn from a chart of accounts where salaries and delivery costs sit in one bucket is not measuring what you think it is. Fix the classification first and run the comparison next year.

How to find the leak

Work from the biggest slice down and compare two matched periods. Start by splitting gross margin by product or service line. Then by channel. Then by the ten largest customers. One of those three cuts usually makes the cause obvious because the overall decline resolves into two or three lines that moved hard while everything else held.

Then separate three effects rather than blending them. Price effect is what happened to realised price per unit including every discount and credit note. Mix effect is what happened because the share of your sales moved towards lower margin lines even though no individual price changed. Cost effect is what happened to input cost per unit. Mix effect is the one owners consistently miss and the one growth creates.

Check the channel costs that scale silently with volume. Marketplace commission, payment gateway charges, courier rates above a weight break, return handling and advertising cost per order all rise as you reach further for demand. Each is small per order and each is deducted before you ever see the money.

Which figures to trust

Realised margin per unit by line is the number that matters. Realised means after discount, after credit notes, after commission and after delivery. Track it monthly for your top lines once you have it.

Absolute gross profit flatters. A business can grow gross profit in rupees every year while each sale earns less and the trend only becomes visible when growth stops. Revenue growth flatters for the same reason. Average margin across the whole business flatters hardest of all because a strong line and a loss making line average into something that looks acceptable.

The common mistake

The common mistake is responding to a gross margin problem by cutting overheads. Overheads are visible and easy to cut so the marketing budget goes or a role stays unfilled. Gross margin is set below that line and nothing about the leak has changed. The following year the same decline repeats with less capability in the business to respond to it.

The second version is leaving the discount authority of a sales team unexamined. Discretionary discounting granted deal by deal never appears as a line item anywhere. It arrives as a slightly lower realised price across hundreds of invoices and that is exactly what a margin decline looks like from the outside.

This guide explains how something works. It is not legal, tax or financial advice, and rules change. Confirm anything regulatory with a qualified professional before you act on it.