Can unusually high profit margins make buyers suspicious instead of impressed?

Yes, and this surprises a lot of sellers who assume higher numbers are always a straightforward advantage. Margins significantly above what's typical for your industry tend to prompt buyers and their advisors to ask why, and if the answer isn't a clear, sustainable advantage, such as a genuinely better cost structure, pricing power, or efficiency, the alternative explanations a buyer will consider include understated expenses, unusual accounting treatment, or a temporary situation that won't continue under new ownership.

The nuance is that unusually high margins aren't a problem in themselves; the issue is when they're unexplained. A business with a real, defensible reason for outperforming its industry, backed by consistent financial records, can turn that same margin into a genuine selling point rather than a source of suspicion.

Being ready to explain, clearly and with documentation, why your margins look the way they do, rather than treating a strong number as self-evidently good news, protects your credibility during due diligence. A business lawyer and accountant can help you frame that explanation before a buyer's advisors form their own theory about it first.