Why it matters most
A famous 1986 study by Brinson and colleagues found that over 90% of the variation in pension fund returns came from asset allocation, not stock picking. Mixing assets that don't move in lockstep lowers risk for a given return, the core idea of modern portfolio theory.
Common strategies
The 60/40 portfolio is the classic. Ray Dalio's All Weather spreads risk across growth and inflation scenarios. Target-date funds shift from stocks to bonds as retirement nears. When markets knock your mix off target, rebalancing brings it back.
FAQ
- What's the right stock percentage?
- It depends on age, goals, and risk tolerance; "110 minus your age" is a rough starting point.
- Does diversification prevent losses?
- No, it reduces them but doesn't eliminate them.
Sources reviewed: 2026-10-26
References
- Brinson, G. P., Hood, L. R., & Beebower, G. L. (1986). Determinants of portfolio performance. Financial Analysts Journal, 42(4), 39–44.
- Markowitz, H. (1952). Portfolio selection. Journal of Finance, 7(1), 77–91.
