📖Warren Buffett

Diversification vs Concentration

🌿 Intermediate★★★★☆

Wide diversification is a hedge for ignorance; deep knowledge justifies concentration.

💬

Wide diversification is only required when investors do not understand what they are doing.

— 1996 Berkshire Hathaway Annual Shareholders Meeting，1996

🏠 Everyday Analogy

Just like cooking, if you are a professional chef, specializing in a few signature dishes can sustain a restaurant. But if you are an amateur, it’s safer to order takeout or a platter. Knowing a little about everything but mastering nothing often leads to failure in the kitchen.

📖 Core Interpretation

Diversification is the right approach for most investors (e.g., buying index funds), but for those capable of conducting in-depth research, concentrated investing holds greater advantages.
💎 Key Insight：If you don't know what you're doing, diversify broadly — buy an index fund. But if you've done deep research and truly understand a business, concentrating your portfolio in your best ideas produces superior returns. Buffett's top 5 holdings often represent 70%+ of Berkshire's equity portfolio. Conviction backed by knowledge beats diversification.

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❓ Why It Matters

The Cost of Diversification: Diluted returns, superficial research, and difficulty in tracking. The Advantage of Concentration: In-depth research, high focus, and significant return potential.

🎯 How to Practice

Ordinary investors should diversify (into index funds). Investors with the capability to conduct in-depth research may concentrate their holdings in 5–10 positions.

🎙️ Master's Voice

Wide diversification is only required when investors do not understand what they are doing.
If you truly understand a business, concentrating makes sense. Buffett has had up to 40% in a single stock. But if you're uncertain, diversification protects against your ignorance. The right approach depends on your knowledge level.

⚔️ Practical Guide

✅ Decision Checklist

  • Do I understand my holdings well enough to concentrate?
  • Am I diversifying due to knowledge or fear?
  • Could I discuss each holding for an hour?
  • Is my diversification appropriate for my expertise?

📋 Action Steps

  1. Match concentration to confidence
  2. Concentrate in your best ideas
  3. Diversify in areas of less knowledge
  4. Never concentrate in what you don't understand

🚨 Warning Signs

  • Concentrating without deep understanding
  • Diversifying as a crutch for poor research
  • Equal-weighting regardless of conviction
  • Concentration in speculative bets

⚠️ Common Pitfalls

✕Concentrated investing is superior - but only for investors capable of conducting in-depth research.
✕Diversification is safety - but diversifying into assets you don't understand can be even more dangerous.

📚 Case Studies

1
Buffett's Concentration (2016)
Apple once accounted for over 40% of Berkshire Hathaway's investment portfolio.
✨ Outcome：Concentrated Holdings Based on In-Depth Research
2
Retail Investor (1996)
Purchase of S&P 500 Index Fund
✨ Outcome：Simple and Effective Diversification Strategy

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