Write about the efficient portfolio.

An efficient portfolio is a combination of assets that provides the highest expected return for a given level of risk (or the lowest risk for a given level of return). It lies on the efficient frontier, a curve representing portfolios that optimally balance risk and return.

Key characteristics:

• No dominated portfolios: No other portfolio offers higher returns for the same risk or lower risk for the same return.
• Diversification: Reduces unsystematic risk (company-specific risk) by combining assets with low or negative correlations.
• Mean-variance optimization: Based on Harry Markowitz’s theory, where investors choose portfolios based on expected return and variance (risk).

The efficient frontier is derived by plotting portfolios with varying risk-return combinations, excluding those that are inferior. Investors then select a portfolio based on their risk tolerance.