📖Benjamin Graham

Diversification

🌳 Advanced★★★★★

Spread investments across multiple securities to reduce the impact of any single wrong decision.

💬

Diversification is an established tenet of conservative investment.

— _The Intelligent Investor_，1949

🏠 Everyday Analogy

Just as a farmer does not plant only one type of crop but instead sows wheat, corn, soybeans, and other varieties—so that if pests or natural disasters strike, at least other crops can secure the harvest—the same principle applies to investing. By purchasing stocks across different industries and companies, even if one company encounters problems, your other investments can still safeguard your wealth.

📖 Core Interpretation

Diversification is a fundamental principle of conservative investing, as it helps mitigate individual stock risk.
💎 Key Insight：Diversification acknowledges that even the best analysis can be wrong. Graham recommends holding a minimum of 10 and maximum of 30 different securities to reduce unsystematic risk. Concentration may offer higher upside, but diversification protects against the catastrophic loss that permanently destroys capital.

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❓ Why It Matters

Even with correct analysis, individual stocks can still fail due to unforeseen events.

🎯 How to Practice

Hold 10 to 30 stocks across different industries and categories.

🎙️ Master's Voice

Obvious prospects for physical growth in a business do not translate into obvious profits for investors.
Graham warned that growth is often overpriced. A growing industry or company may still be a poor investment if the growth is already reflected in the price. Do not confuse growth with value.

⚔️ Practical Guide

✅ Decision Checklist

  • Is growth already priced in?
  • Am I paying too much for growth prospects?
  • Will growth translate into shareholder returns?

📋 Action Steps

  1. Evaluate whether growth is already in the price
  2. Calculate what growth rate is implied by current price
  3. Consider whether growth will benefit shareholders

🚨 Warning Signs

  • Paying any price for growth
  • Assuming growth equals profit
  • Ignoring valuation for growth stories

⚠️ Common Pitfalls

✕Excessive diversification dilutes returns.
✕However, for the defensive investor, diversification is even more critical.

📚 Case Studies

1
Pre-Crash Overconcentration (1929)
An investor held mostly speculative industrial stocks before the 1929 crash, ignoring bonds and defensive issues Graham advocated.
✨ Outcome：Portfolio fell over 80%. A diversified mix of quality bonds and stocks would have limited losses and preserved capital for the recovery.
2
Cuban Missile Crisis Diversification (1962)
A Graham-style defensive investor held blue-chip stocks, high-grade bonds, and cash during the 1962 market break.
✨ Outcome：Equities declined sharply, but bond stability and cash reserves limited drawdowns and allowed buying quality stocks at lower prices before markets recovered.

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