Efficient frontier
Also: efficient frontier, Markowitz frontier, mean-variance frontier
The set of portfolios offering the highest expected return for each level of risk, derived from mean-variance optimization. Portfolios below the frontier are inefficient; portfolios above it are unattainable with the input assumptions.
The efficient frontier, from Harry Markowitz’s mean-variance framework, is the curve of portfolios that maximize expected return for each level of risk (standard deviation). The calculation requires expected returns, volatilities, and pairwise correlations for every asset class. The lowest-risk point is the minimum variance portfolio, typically heavy in bonds. The highest-return point is 100% in the highest-return asset, typically small-cap equity. Practical portfolios aim for a point on the curve that matches the investor’s risk tolerance.
Example: a 40-year-old tech employee sits on an advisor-built frontier with asset classes: US stocks, international stocks, bonds, REITs, and cash. The 75% stock / 25% bond portfolio sits on the frontier at 12% expected return and 14% volatility. Shifting to 90% stock raises expected return to 13% but raises volatility to 16.5%, a 3-point increase in risk for only 1 point of return.
Common mistake: treating the frontier as precise. Small changes in expected return assumptions shift allocations dramatically, which is why professional portfolios use sensitivity testing rather than single-point optimization.
The efficient frontier matters at long-term asset allocation decisions, at post-IPO portfolio restructuring, and at evaluating advisor-recommended portfolios.