The Margin of Safety — Investing's Most Important Concept

What if you could be wrong — genuinely wrong — about a business and still make money? The margin of safety is the principle that makes this possible. It is not a strategy for being right. It is a strategy for surviving being wrong.

Why This Matters

Every estimate of a business's intrinsic value involves assumptions about the future. Future earnings, future growth rates, future competitive dynamics — none of these can be known with certainty. Even the most rigorous analysis can be undone by an unforeseen event, a management misjudgement, or a market shift no one predicted. Graham's response to this uncertainty was not to try harder to predict the future. It was to demand a cushion — a gap large enough between price paid and value received that even a substantially worse outcome than expected would still produce an acceptable result. This cushion is the margin of safety.