📖William Gann

Review Your Investment Thesis

🌿 Intermediate★★★★☆

Regularly challenge your original investment thesis.

💬

Regularly review whether your original reasons for owning a stock still hold. If the facts change, change your mind. Holding a broken thesis is the costliest mistake.

— 45 Years in Wall Street,1949

🏠 Everyday Analogy

Long-term investing is like planting trees. Early progress looks slow, but compounding happens underground before it becomes visible.

📖 Core Interpretation

W.D. Gann frames investing as a compounding game. Time amplifies quality and discipline, while unnecessary activity often destroys long-horizon returns.
💎 Key Insight:Adapting to new facts prevents holding broken investments.

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❓ Why It Matters

Short-term noise often forces investors out before value is realized. Long-term discipline increases the odds that fundamentals, not emotions, drive outcomes.

🎯 How to Practice

Extend research and review horizon, reduce unnecessary turnover, and adjust only when intrinsic value, risk, or opportunity cost materially changes.

⚠️ Common Pitfalls

Calling it long term while never reviewing thesis
Overtrading and damaging compounding
Ignoring opportunity cost and alternatives

📚 Case Studies

1
Post-Crash Accumulation (1932)
After the 1929–1932 bear market, Gann used square-of-9 time and price levels to signal a long-term bottom in the Dow Jones.
✨ Outcome:He accumulated quality stocks near the lows and benefited from the ensuing multi‑year recovery rally.
2
Railroad Stock Forecast (1909)
Gann reportedly applied Gann Angles to predict turning points in several railroad stocks, including Union Pacific, correctly forecasting price reversals based on angle support and resistance from key swing lows.
✨ Outcome:Executed multiple short-term trades with favorable risk-reward, compounding returns over several months.

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