The authors argue that a 100-year portfolio is defined more by governance and process than by a fixed allocation. They favor real assets and regime diversification as AI, climate, inflation, and geopolitics widen uncertainty, while estimating 4.5% long-run real US equity returns versus 6.7% over the past century.
The 100-Year Portfolio: A State of Mind Rather Than an Allocation
AllianceBernstein
Inigo Fraser Jenkins
Research
19 Pages
Key Takeaways
Time changes risk: Since 1900, one-year equity volatility was 20% versus 7.5% for 10-year government bonds, converging at 2.6% over 26-year holding periods.
Inflation tests 60/40: Across the past century, a 60/40 portfolio’s chance of beating inflation approaches a coin flip, despite unusually strong post-1980 performance.
Returns may normalize: AB estimates 4.5% long-run real US equity returns, versus 6.7% over the past century, before any valuation mean reversion.
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