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How to double a Sharpe ratio

Alternative investments have proved their worth. Witness the estimated $1 trillion under management in alternative assets, or the recent decision by major pension funds such as Calpers or British Telecomto to allocate up to 5% of their portfolio to alternative assets. And yet, standard risk-adjusted performance indicators often prove unsuitable for hedge funds, which rely on highly specific tec...

Sharpe Ratio Practice Note

The Sharpe Ratio Efficient Frontier

We evaluate the probability that an estimated Sharpe ratio exceeds a given threshold in presence of non-Normal returns. We show that this new uncertainty-adjusted investment skill metric (called Probabilistic Sharpe ratio, or PSR) has a number of important applications: First, it allows us to establish the track record length needed for rejecting the hypothesis that a measured Sharpe ratio is b...

The Statistics of Sharpe Ratios

The building blocks of the Sharpe ratio—expected returns and volatilities— are unknown quantities that must be estimated statistically and are, therefore, subject to estimation error. This raises the natural question: How accurately are Sharpe ratios measured? To address this question, I derive explicit expressions for the statistical distribution of the Sharpe ratio using standard asymptotic t...

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