The Most Quoted Margin Is the Least Comparable One

Net income is not cash

Two large items sit between the net margin and the bank account, and they pull in opposite directions. Depreciation reduces net income without any money leaving, so a capital-heavy business generates more cash than its margin suggests. Buying the equipment in the first place removes cash without touching net income at all, because the purchase becomes an asset rather than an expense. A year of heavy investment therefore shows a healthy margin and a falling balance, and a year of running down the machinery shows the reverse. The cash flow statement exists precisely because the income statement cannot answer that question.

Comparing across borders compares tax codes

Tax sits inside the net margin and outside the control of the people running the business, so a difference of ten points of corporate tax rate moves the net margins of two otherwise identical companies apart by a proportional amount. The effect is larger than the rates alone suggest, because what is taxable also differs: research credits, depreciation schedules and the treatment of interest vary enough that two companies with the same headline rate can pay very different amounts. Comparing net margins across jurisdictions is therefore a comparison of legislatures. The operating margin is the line to use when the question is about the business.

Frequently asked questions

Then why is the net margin the one everybody quotes?

Because it answers the owner's question rather than the analyst's. What eventually belongs to the shareholders is net income, after everyone else has been paid, so for someone deciding whether to hold the shares it is the right final figure. The mistake is not quoting it — it is using a number designed to summarise one company's outcome as a tool for ranking several. Read the net margin for a verdict on a single business, and the operating margin whenever a second business enters the sentence.

Can a net margin exceed the gross margin?

Only through income that did not come from selling anything. A gain on disposing of a property, a legal award, a tax credit or investment income can all push the bottom line above what the trading operation earned, and in a year with one of those the two margins invert. It is a reliable signal that something unusual happened rather than that the business improved, and the annual report will say what — the note explaining the item is the point of reading it. A sustained inversion means the company's earnings are coming from somewhere other than what it appears to do.