A sustainable competitive advantage that allows a business to fend off competitors and maintain high returns on capital for long periods. Buffett described it as a "城堡" (castle) protected by a moat — the wider and more durable the moat, the more valuable the business.
| Year | Relevance |
|---|---|
| 1977 | first |
| 1986 | key |
| 1988 | key |
| 2025 | key |