The Value Investor's Decision System

Analysis tells you whether a business is good. The decision system tells you what to do about it — and when. Every value investor eventually confronts the gap between "I know this business is worth more than the market is paying" and "I know exactly when and how much to buy, what to do when the price falls further, and when my thesis has genuinely broken." The decision system is the bridge between analytical conclusion and portfolio action.

Why This Matters

Buffett, Munger, and the Graham tradition have generated extensive documentation of their decision rules — not as explicit formal systems, but as principles repeated consistently across letters, interviews, and books. This decision system distills those principles into their most actionable form: when to act, at what size, and when to stop. The value investor's decision system is defined by patience. The average holding period in a great value portfolio is measured in years, sometimes decades. The decision to buy is made slowly and deliberately. The decision to sell is rarer still. Most of the time, the correct action is to do nothing.