For the first time in a decade, European equities have broken out of their constantly widening valuation discount range compared to the US. Historically, such breakouts have signaled the beginning of a long-term upward trend where the valuation gap narrows significantly.

The S&P 500's historical earnings growth is ~6.7%. The ~9% growth of the last decade was an exception, driven by the unprecedented hyper-growth of a few mega-cap tech firms. As the law of large numbers catches up to these giants, investors should anticipate future index returns to revert to historical, lower norms.

Historical data shows no exceptions to the rule that an asset class reaching a two-standard-deviation (two sigma) valuation above its long-term trend will eventually return to that trend. This statistical certainty applies to stocks, bonds, commodities, and currencies, making severe drawdowns from such peaks inevitable.

Historically, small-cap companies grew earnings faster than large-caps, earning a valuation premium. Since the pandemic, this has flipped. Large-caps have seen astronomical earnings growth while small-caps have lagged, creating a rare valuation discount and a potential mean reversion opportunity for investors.

Emerging vs. developed market outperformance typically runs in 7-10 year cycles. The current 14-year cycle of EM underperformance is historically long, suggesting markets are approaching a key inflection point driven by a weakening dollar, cheaper currencies, and accelerating earnings growth off a low base.

Market-cap weighting turned the S&P 500 into a momentum fund for megacaps, leading to a decade of outperformance versus its equal-weight counterpart—a historical anomaly. Recent signs of equal-weight taking the lead suggest a potential market regime shift back towards value and smaller companies.

For the first time in a decade, European equities have broken out of their long-term trend of a widening valuation discount versus the US. Historically, such breakouts signal the beginning of a sustained, multi-year period where this valuation gap narrows significantly from its current 23%.

Contrary to a common myth, high equity valuations do not reliably revert to a historical mean. An analysis of 32 different valuation scenarios found only one case of statistically significant mean reversion. Structural economic shifts, like reduced GDP volatility since the 1990s, justify higher sustained valuation levels.

Across 200 years and 56 countries, the single most important factor for long-term investing success is the starting valuation. Buying portfolios with low P/E ratios or high dividend yields consistently outperforms buying expensive assets by 3-4% annually over the long run.