What a moat is
A moat is a lasting advantage that stops competitors from taking a company's customers or profits. The term comes from Warren Buffett: a castle (the business) is only as safe as the moat around it.
Without a moat, high profits attract competitors, and competition pushes prices and margins down. With one, a company can earn high returns for years.
What makes a company worth holding
Four things, together:
- Durable revenue growth. See Revenue growth (TTM and forward).
- Strong margins. See Gross margin.
- A healthy balance sheet. See Balance sheet strength: cash versus debt.
- A moat that protects the first three.
The five main types
| Moat | How it works | Typical example |
|---|---|---|
| Switching costs | Leaving is painful, costly or risky for the customer | Business software built into daily work |
| Network effects | Each new user makes the product more valuable to others | Marketplaces, payment networks, social platforms |
| Scale | Being biggest makes each unit cheaper to produce or deliver | Large retailers, chip foundries, cloud providers |
| Patents and regulation | The law limits who can compete | Drug makers, licensed utilities, exchanges |
| Brand | Customers pay more, or choose it by default, because of the name | Premium consumer goods |
How to spot one in the numbers
A moat shows up in the financials before it shows up in marketing:
- High and stable Gross margin. Pricing power means the company does not have to discount.
- High Return on invested capital (ROIC). Each dollar reinvested earns well above the cost of capital, year after year.
- Margins holding up in bad years. A weak moat shows when demand slows.
Moats change
Moats widen and shrink. Leaders can grow complacent, especially when decisions shift from engineers and product people to legal, sales and finance. Reassess the moat each year, not just when you buy. See Market leadership cycles.
See also
- Gross margin What gross margin is, what it reveals about pricing power, typical ranges by industry, and why its trend matters as much as its level.
- Return on invested capital (ROIC) ROIC shows how much profit a company earns on the money invested in it. Why it is the best single test of a moat, and how it compares with ROE.
- How to research a company A step-by-step way to research a stock: understand the business, run a SWOT, apply the double-or-halve test, then check the numbers and valuation.
- Market leadership cycles Why the companies that lead one decade rarely lead the next, how sector leadership rotates, and what that means for concentration and diversification.
Pages that link here: Building your investing knowledge, Finviz screener guide, Fundamentals checklist, The double-or-halve test
Last updated September 30, 2026. Education only, not investment advice.