Net margin: the very first filter in my method

2026-07-07 · By Lubin Danilo, founder of Lubin Investment

Before looking at a company's growth, debt, or valuation, I check one simple thing: does it actually make money? Net margin, the percentage of every dollar of sales that becomes profit, is the very first filter in my method. A basic number, but one that already screens out a large part of the market.

Key takeaways

Net margin measures how much of every dollar of sales becomes profit, after all expenses are paid.
It's the very first of the ten criteria in my method: a company that isn't even profitable doesn't pass this basic filter.
Cintas, which I've analyzed on my site, shows a 17.6% net margin, a solid level for a services business.
Omnicom, by contrast, shows an accounting net margin of just 0.3%, a figure worth nuancing since it's distorted by one-off items from a recent acquisition.

The most basic filter, and yet essential

Before turning to more sophisticated criteria (cash growth, return on capital, debt), I always start with the most elementary question: does this company make money? Net margin answers that directly: it shows what percentage of every dollar of revenue becomes net profit, after paying all costs, taxes, and debt interest.

It's a deliberately simple filter, but it already screens out a significant share of publicly traded companies: many fast-growing businesses, especially in tech or developmental biotech, simply aren't profitable, whatever their other qualities. That's not a moral judgment on those companies, just a signal that my approach, focused on already-profitable businesses, doesn't apply to them yet.

The Cintas case: solid services-business profitability

Cintas, the global leader in corporate uniform rental which I've analyzed on my site, shows a 17.6% net margin. For a services business (renting and maintaining professional uniforms), that's a solid level reflecting real pricing power and efficient operations, well above what you see in many lower-value-added service businesses.

The Omnicom case: a figure that needs nuance

Omnicom, the advertising group I've also analyzed, shows an accounting net margin of just 0.3%, a figure that looks alarming at first glance. But that figure is distorted by one-off charges tied to a recent acquisition, which weigh on reported earnings without reflecting the real, recurring profitability of the business. This is exactly the kind of case where I always cross-check accounting net margin against free cash flow margin, harder to distort with non-recurring items: Omnicom's comes in at 14.5%, a far more representative level.

Why a single number is never enough

The Omnicom example illustrates well why I never rely on a single isolated number, even one as basic as net margin. A reported result can be temporarily distorted by one-off items (acquisitions, write-downs, litigation) that have nothing to do with the underlying profitability of the business. Net margin remains an essential starting point, but it must always be cross-checked with other signals, especially cash actually generated.

What I take away from this

Net margin is the first of the ten criteria I apply, precisely because baseline profitability is a non-negotiable prerequisite before looking at a company's growth, valuation, or moat. But this basic filter must be read with judgment: a temporarily low figure doesn't always mean a bad company, it can simply signal that you need to dig further before concluding anything.

FAQ

What is net margin?

It's the percentage of every dollar of revenue that becomes net profit, after paying all costs, taxes, and debt interest.

Why is net margin the first criterion in my method?

Because baseline profitability is a non-negotiable prerequisite: a company that doesn't make money can't yet be judged on more sophisticated criteria like growth or valuation.

Why is Omnicom's net margin so low?

That 0.3% accounting figure is distorted by one-off charges tied to a recent acquisition. The more reliable free cash flow margin comes in at 14.5%.

Does a low net margin always mean a bad company?

No, you should always check whether the figure is distorted by one-off items before concluding anything, cross-checking it especially with the free cash flow margin.

What's a good net margin level for a services business?

Cintas, for example, shows 17.6%, a solid level reflecting real pricing power for this type of business.

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About the author

Written by Lubin Danilo, founder of Lubin Investment. A self-taught individual investor, I find fundamental analysis fascinating, and it has delivered excellent results. For three years now, my performance has beaten the S&P 500. But analyzing every stock took too much time: sites with incomplete data, calculation methods and criteria never aligned with mine. And spotting the best stocks was just as time-consuming, even with my own well-defined checklist. So I put my software development background to work to build this software, base my investment strategy on its results, and share it with people who share the same passion as me. It judges a company's quality and its price separately, using criteria drawn from the financial literature (Warren Buffett, Michael Mauboussin, Aswath Damodaran).