Economic Moat

Overview

An economic moat is the durable, structural competitive advantage that protects a business's returns on capital from being competed away. Popularized by Warren Buffett (1986 Berkshire letter); codified into five sources: intangible assets, switching costs, network effects, cost advantages, efficient scale. Greenwald's test: if you cannot name a specific mechanism that would cost a well-funded rival years and tens of millions to overcome, you have execution — not a moat.

Composes with network-effects and switching-costs (two moat sources, deeper treatment), porters-five-forces (industry-level; moat is company-level), margin-of-safety (wide moat × discount price = Buffett formula), lindy-effect (long survivors demonstrate moat durability).

When to Use

• Evaluating an investment, competitor, acquisition, or startup strategy for long-term defensibility
• Founder-board planning or investor pitch review around "what stops competitors"
• Someone says "moat," "defensibility," "competitive advantage," or "what stops competitors"
• Assessing durability amid the AI build-out — AI capex, chip export controls, "is the AI boom a bubble," or which infrastructure players (e.g. Nvidia/CUDA, TSMC) keep their returns

Not when: short time horizon; commoditized market (confirms "no moat"); question is immediate execution.

Coaching Novices (Adaptive Front Door)