Billionaire Investor Bill Ackman Bets Big and Wins Big. Is a Concentrated Portfolio Approach for Everyone?

The article discusses the merits and risks of concentrated portfolios, noting that while hedge funds often utilize them due to their access to resources and information, individual investors are generally better off with diversified portfolios through index ETFs like the Vanguard S&P 500 ETF (VOO). A J.P. Morgan study found that a significant percentage of stocks underperform or experience catastrophic declines, further supporting the case for diversification for retail investors.

Analysis

The article contrasts the concentrated investment strategies often employed by renowned investors like Bill Ackman and other hedge funds with the merits of diversification for average investors. Professional investors may favor concentration (e.g., 15-20 long positions) due to performance-based incentives and access to superior resources, including expert networks, proprietary data, and direct management contact, which can provide an analytical edge. However, this approach carries significant risk, as illustrated by the J.P. Morgan study (1980-2020) which found that approximately 40% of Russell 3000 stocks delivered negative returns, two-thirds underperformed the index, and another 40% experienced catastrophic declines of 70% or more without full recovery. This data underscores the difficulty of successful stock picking. Consequently, for individual investors lacking such extensive resources, the article advocates for diversified index exchange-traded funds (ETFs) like the Vanguard S&P 500 ETF (VOO). The S&P 500's market-cap weighted structure, where winning stocks naturally increase their index weighting, is presented as a key reason for its historical outperformance over many professional managers, who may prematurely trim winners or average down on losers. While acknowledging that some professionals can succeed with concentration, the inherent difficulty and risk profile make it less suitable for those without a significant informational advantage.

Key Decisions for Investors

• Institutional investors maintaining concentrated long portfolios should continuously affirm that their proprietary research and informational advantages are robust enough to counteract the significant historical underperformance and failure rates of individual stocks, as highlighted by the J.P. Morgan study.
• Portfolio managers should evaluate their active stock selection and position-sizing strategies against the structural benefits of market-cap weighted indices, such as the S&P 500 (tracked by VOO), which intrinsically allow successful investments to compound and contribute more to overall returns.
• Given the asymmetric risk profile of short selling, where adverse movements can rapidly increase a position's size and impact, maintaining stringent diversification and risk management protocols within short portfolios remains critical, regardless of conviction levels in individual short theses.