Why Diversification Beats Stock Picking | The Informed Investor 46

Episode 46: Are 30 stocks enough to build a truly diversified portfolio? We seek to answer one of investing's most debated questions: How many stocks does an investor really need to own to reduce risk and improve long-term outcomes? While traditional financial research once suggested that owning 20 to 30 stocks captured most diversification benefits, today's global markets may tell a very different story. The discussion dives into the evolution of diversification theory, from the early days of Modern Portfolio Theory and Harry Markowitz to the modern reality of investing across more than 40 countries and thousands of publicly traded companies. We examine why a concentrated portfolio of 30 stocks may expose investors to greater risks tied to countries, sectors, and individual companies—and why broad diversification can provide better flexibility, lower implementation costs, and potentially more reliable outcomes over time. Using real-world examples, including return differences between countries like Spain and Denmark, as well as performance gaps between companies in the Magnificent 7, the conversation highlights how difficult it can be to consistently "pick the winners." We also touch on concepts like tracking error, sampling strategies in index funds, securities lending, investor discipline, and the trade-offs between concentration and diversification. Importantly, the discussion goes beyond investing in stocks alone as we explore how diversification applies to fixed income portfolios, including why bond diversification should be aligned with an investor's goals, risk management needs, and time horizon. In Episode 46 of The Informed Investor, Dimensional's Mark Gochnour, Head of Global Client Services, Wes Crill, Senior Client Solutions Director, and Jake DeKinder, Head of Client Communications, take a practical and thought-provoking look at what diversification really means in today's investment landscape, whether you're building a portfolio yourself or working with a financial advisor. Subscribe to the Stay Calm Investing Newsletter https://www.staycalminvesting.com/newsletter   The Informed Investor Feedback Survey https://www.dimensional.com/us-en/informed-investor-survey   The Informed Investor on YouTube  https://www.youtube.com/playlist?list=PLCyJr6FFig-h1mA7rVP7Mbk0irFw2wA90 Dimensional Fund Advisors Shorts on YouTube https://www.youtube.com/@dimensionalfundadvisors/shorts   Mark Gochnour on LinkedIn https://www.linkedin.com/in/mark-gochnour-9a23598a/   Wes Crill on LinkedIn https://www.linkedin.com/in/wes-crill-77a49417/   Jake DeKinder on LinkedIn https://www.linkedin.com/in/jake-d-4105b98/   Learn more at https://www.dimensional.com/