What Is a Moat?

An economic moat is a business's durable competitive advantage — something that protects its profits from competitors the way a water-filled ditch once protected a castle from invading armies. The metaphor comes from Warren Buffett, who has used it for decades to explain why he prefers businesses that can defend high returns on capital for years or even decades, rather than businesses that happen to be profitable today but have nothing stopping a rival from copying them tomorrow.

"A truly great business must have an enduring “moat” that protects excellent Returns on Invested Capital." — Warren Buffett

Why Moats Matter

In a competitive market, profits attract imitators. If a business earns unusually high returns and has no structural protection, competitors will rush in, undercut prices, or copy the product until those returns are driven back down to an ordinary level. A moat is whatever prevents that from happening. It might be a legal protection, a cost structure a rival cannot match, a psychological hold on customers, or simply the sheer difficulty of replicating what the business has built. Companies with wide, durable moats can sustain high ROIC for long stretches, which is a major reason moat analysis sits at the center of how many investors — value-oriented ones especially — decide which businesses are worth owning for the long run and at what price.

Buffett did not invent the underlying idea that some businesses have more staying power than others; investors and economists had long discussed "barriers to entry" and competitive advantage. What he did was package the concept into a vivid, memorable image that turned abstract industrial-economics analysis into a question any investor could ask about a business: how wide, and how durable, is its moat?

The Different Types of Moat

Not all moats work the same way, and recognizing which kind (if any) protects a given business is central to judging how long its advantage might last. Analysts generally group durable competitive advantages into a handful of recurring types, each covered in more depth elsewhere in this resource library:

Intangible assets — brands, patents, and regulatory licenses that competitors cannot legally or practically replicate.
Cost advantage — the ability to produce goods or services more cheaply than rivals, whether through scale, location, process, or access to unique resources.
Pricing power — the ability to raise prices without losing meaningful volume, usually because customers see few good substitutes.
Network effect — a product or platform that becomes more valuable to each user as more people use it, making it self-reinforcing.
Switching costs — the money, time, or hassle a customer would face moving to a competitor, which locks in existing relationships.
Efficient scale — a market small enough that it profitably supports only one or a few players, discouraging new entrants.

Reading Moats Correctly

A moat is not a permanent certificate; it's a current condition that can widen, narrow, or disappear as industries evolve. Buffett himself has emphasized that he cares less about a company's current size or growth rate than about how confident he can be that its competitive position will still be intact ten or twenty years from now. That's why moat analysis tends to focus on structural, hard-to-copy sources of advantage rather than temporary edges like a head start on a new product or a favorable news cycle — those can evaporate quickly, while a genuine moat tends to compound in the owner's favor year after year. Learning to tell the two apart is one of the more valuable skills an investor can develop, and it starts with understanding the specific mechanisms — the six types above — through which a moat can actually form.