Diversification vs. Concentration: A Buffett-Graham Debate

While Graham taught Buffett the value of diversification, Buffett's shift towards concentrated investments reflects a strategy evolution, emphasizing depth of understanding over breadth of portfolio

Key Takeaways

  1. Graham's Diversification Principle: Emphasizes risk mitigation through broad portfolio diversification, a strategy particularly suited for investors wary of market unpredictability.

  2. Buffett's Concentration Strategy: Advocates for investing substantial amounts in a few well-researched companies, highlighting the potential for higher returns with a deep understanding of select investments.

  3. Buffett's Adaptability in Investment: Exhibits flexibility in his principles, as seen in his strategic diversification with Japanese trading companies, balancing his typical concentrated approach with market-driven opportunities.

  4. Evolution of Investing Philosophies: Both Graham and Buffett adapted their strategies over time, indicating the importance of evolving investment approaches in response to changing market conditions.

  5. Integrating Diversification and Concentration: Suggests a hybrid approach for modern investors, combining the high-growth potential of concentration with the risk mitigation benefits of diversification, tailored to individual risk tolerance and market understanding.

Diversification vs. Concentration: A Buffett-Graham Debate

Investing, a realm filled with diverse strategies and philosophies, often centers on the debate between diversification and concentration. The contrasting approaches of Benjamin Graham and Warren Buffett offer profound insights into this debate. While my own investment philosophy leans towards Buffett's concentrated approach, understanding the nuances of both methodologies is critical.

The Graham School: Diversification as a Safety Net

Benjamin Graham, the mentor of Warren Buffett and the father of value investing, was a firm believer in diversification. His experiences during the Great Depression greatly influenced his investment philosophy, which was centered around risk mitigation. Graham's approach, as he described in "The Intelligent Investor," was to spread investments across a broad spectrum of assets to reduce the volatility and risk in a portfolio. This method was especially suited for the average investor, who Graham believed,

This quote reflects Graham's understanding that the market is inherently unpredictable and full of risks that can be mitigated through a diversified portfolio.

Graham's endorsement of diversification was not merely a tactic to spread risk but also a reflection of his investment philosophy, which emphasized analytical rigor and discipline. He believed that diversification should be grounded in a thorough analysis of each investment's fundamentals. For Graham, it wasn't about owning a large number of stocks for the sake of diversity; it was about choosing a variety of quality stocks that individually met strict criteria for value and potential. This approach was particularly vital for individual investors, whom Graham felt lacked the time and resources to monitor and understand deeply a smaller number of stocks. By diversifying, these investors could still participate in the market's growth while minimizing the impact of any single stock's downturn. Graham's strategy thereby offered a pragmatic blend of caution and opportunity, aiming to achieve consistent returns while safeguarding against significant losses.

The Buffett Twist: Confidence Over Diversification

Warren Buffett, though initially a disciple of Graham's teachings, gradually shifted towards a more concentrated investment approach. His famous adage,

reflects this shift. Buffett believed that thorough research and a deep understanding of a few select companies could lead to better investment decisions than spreading one's investments too thin. A classic example of Buffett's concentrated approach is his investment in American Express in the early 1960s. Following a major scandal that caused the company's stock to plummet, Buffett recognized the enduring value of the brand and the temporary nature of its problems, leading him to invest a significant portion of his portfolio in it, a move that paid off handsomely.

Buffett’s Strategic Diversification in Japan

Warren Buffett’s investment in Japan serves as an intriguing case study in strategic diversification. In 2020, Buffett's Berkshire Hathaway acquired stakes in five major Japanese trading companies: Itochu, Marubeni, Mitsubishi, Mitsui, and Sumitomo. This move was notable, as it marked a departure from his typical investment strategy, which usually involves a concentrated portfolio of deeply understood and closely followed companies. The decision to diversify in Japan was driven by several factors, including the search for value in a relatively undervalued market and the desire for exposure to a diverse range of industries, from commodities to consumer goods. Buffett acknowledged the deviation from his usual approach, stating,

This investment reflects Buffett's adaptability and his willingness to diversify when he sees value and potential, even if it means stepping outside his usual investment paradigm.

This move into the Japanese market illustrates a nuanced aspect of Buffett's investment philosophy. It shows that while he generally favors concentration, he is not averse to diversification when it aligns with his value investing principles and when it offers a strategic advantage. This foray into Japan underscores the importance of context and adaptability in investment decisions, demonstrating that even the most steadfast investment principles can have exceptions based on market opportunities and investor confidence.

The Evolution of Graham’s and Buffett’s Philosophies

It's important to note that both Graham and Buffett evolved their strategies over time, adapting to changing market conditions and personal experiences. Graham, for instance, began to see the value in more concentrated portfolios later in his career, though he always maintained a cautious approach. Similarly, Buffett’s foray into diversification, as seen in his investments in Japan, was a strategic move, reflecting his belief that diversification is appropriate when uncertainty is

high or when confidence in individual investments is not absolute.

Real-World Application: Modern Investing Landscape

Today’s investors operate in a vastly different landscape than that of Graham or Buffett’s early years. The rise of global markets, technological advancements, and the availability of sophisticated investment tools have transformed investing strategies. For instance, the tech industry, characterized by rapid innovation and growth potential, has attracted investors who prefer a concentrated approach, betting on companies like Amazon and Tesla, which have shown remarkable growth. On the other hand, the increased accessibility to international markets and asset classes has made diversification easier and more appealing, especially for those who seek to mitigate risk in volatile markets.

Integrating Both Schools of Thought

In practice, the integration of Graham’s and Buffett’s philosophies can offer a more balanced approach to investing. For example, an investor might concentrate their portfolio on a few well-researched stocks, while still maintaining a level of diversification across different sectors or asset classes. This hybrid approach can provide both the high-growth potential of concentrated investments and the risk mitigation of diversification.


In conclusion, while I advocate for Buffett's concentrated approach in investing, it is essential to understand and respect the merits of Graham's diversification strategy, especially for those who are still building their confidence and expertise in the market. The key is to adapt these philosophies to one's personal investment style and risk tolerance.

For the average investor, this evolution in Buffett's strategy presents an important lesson: while diversification can protect against ignorance and unforeseen market fluctuations, concentration can amplify returns if you have a deep understanding of your investments. It suggests that as you grow in your investment knowledge and experience, you might consider focusing more on a few high-conviction stocks while still maintaining some level of diversification to balance out the risks. The key is to assess your level of knowledge, risk tolerance, and investment goals when deciding how closely to follow either Graham's or Buffett's approach.

I invite you to share your insights and experiences. Are you a proponent of Graham's diversification or Buffett's concentration? Like, share, and follow for more in-depth discussions on investment strategies. Your participation not only enriches our community but also helps keep this platform a thriving hub for sharing valuable investment wisdom.

Happy Investing!

Thank you for reading Invest in Value: Substack for Value Investing . This post is public so feel free to share it.