While equal-weighting avoids concentration risk, it's not a perfect solution. When applied to an index like the S&P 500, it still only includes companies that have already grown large enough to qualify, inheriting a bias towards higher-multiple stocks and excluding deep value opportunities.

Instead of reacting to stock prices, track the combined "owner's earnings" growth of your portfolio companies. This creates a private-equity mindset, focusing on underlying business performance. Over decades, this metric shows strong correlation with portfolio returns and helps maintain long-term discipline.

Instead of using current market-cap weightings, a "forward cap" strategy allocates capital based on extrapolated macroeconomic trends. This means overweighting a sector like tech based on its projected future dominance, essentially "skating to where the puck is going."

A fundamental index (RAFI) naturally creates a value tilt by reweighting companies to their economic footprint. Therefore, its performance should be measured against cap-weighted value indexes, not the total market. Against this proper benchmark, it has added over 2% per year in live performance.

Despite their market dominance, Amazon and Microsoft are excluded from the RAFI Growth Index. Their percentage growth in sales, profits, and R&D is no longer fast enough to rank in the top quartile of U.S. companies, challenging the assumption that all mega-cap tech stocks are automatically high-growth.

When markets are top-heavy and expensive, like in 2000, the concentration risk of market-cap weighting is severe. In the 13 years after the dot-com peak, while the S&P 500 went nowhere, its equal-weighted version doubled, highlighting a powerful de-risking strategy.

Research by Bessenbinder shows that a tiny fraction of "superstar" companies drive all market gains. Since identifying these winners in advance is nearly impossible, indexing ensures you own them by default, capturing the market's overall growth without the risk of picking the wrong stocks.

Financial models struggle to project sustained high growth rates (>30% YoY). Analysts naturally revert to the mean, causing them to undervalue companies that defy this and maintain high growth for years, creating an opportunity for investors who spot this persistence.

Market cap indexing acts like a basic trend-following system by buying more of what's rising. However, its Achilles' heel is the lack of a valuation anchor, causing investors to over-concentrate in expensive assets at market peaks. In high-valuation environments, almost any other weighting method, like equal-weight or value, is likely to outperform over the long term.