Economic Moat
An economic moat is a durable competitive advantage that protects a company’s profits from competitors: switching costs, network effects, brands with pricing power, cost advantages, or regulatory barriers. It is what separates a good year from a good business.
The math
Moats show up in numbers before they show up in stories. High returns on capital attract competition; economics says those returns should erode toward average.
So the test is arithmetic: a company holding, say, 20 percent returns on invested capital and stable-or-rising operating margins for a full decade is visibly repelling competition. Without a moat, that decade of excess profit should not exist.
The durability of the number is the proof of the moat.
The trap
Buying the story instead of the evidence. Every annual report claims a competitive advantage; most are describing momentum, not a moat.
Fast growth, a hot product, or a famous brand can all coexist with zero pricing power. The reverse trap costs just as much: paying any price for a real moat.
A genuine fortress bought at 50 times earnings can deliver mediocre returns for years while the valuation deflates.
The move
Demand numerical proof before narrative: a decade of returns on capital above the cost of capital, margins that held through recessions, and prices the company raised without losing customers. Then name the moat’s source specifically: what exactly stops a well-funded competitor? If the answer takes more than two sentences, the moat is probably a story.
Moat first, valuation second, and never one without the other.