Definition
Sharpe Ratio Optimisation
Sharpe ratio optimisation is the process of constructing or tuning a portfolio or strategy to maximise return per unit of risk, measured as excess return divided by volatility.
Quant portfolio construction in India often frames the goal as maximising the Sharpe ratio rather than raw return, since a strategy that earns more but with far higher volatility may be inferior on a risk-adjusted basis. Mean-variance optimisation explicitly searches for the highest-Sharpe allocation.
Naively maximising in-sample Sharpe is dangerous: it tends to overfit, loading on whatever looked best historically. Robust approaches use shrinkage of covariance estimates, constraints, and out-of-sample validation. The deflated Sharpe ratio further discounts results that were found after extensive searching.
Related terms
- OverfittingOverfitting, or curve-fitting, occurs when a strategy is tuned so closely to historical data that it captures random noise rather than a genuine pattern, and consequently fails on new data.
- Alpha vs Beta SeparationAlpha-beta separation is the framework of distinguishing returns earned from broad market exposure (beta) from returns earned through skill or unique strategies (alpha), and managing each independently.
- Risk ParityRisk parity is a portfolio construction approach that allocates capital so that each asset or asset class contributes equally to total portfolio risk, rather than weighting by capital invested.
- Kelly CriterionThe Kelly criterion is a position-sizing formula that determines the fraction of capital to risk on a bet or trade to maximise the long-run growth rate of wealth, given the edge and odds.
Plain-English explainer from The Dispatch Investors Encyclopedia. General information, not financial advice.