437 bytes added
, 02:49, October 24, 2011
The '''Sharpe ratio''' is a financial measure of the compensation (called a "risk premium") an investor receives for bearing an additional unit of risk. It is defined as
: <math>S = \frac{E(r) - r_f}{\sigma} </math>
where <math>E(r)</math> is the asset's expected return, <math>r_f</math> is the risk-free rate (normally, the rate of return of a United States T-bill) and <math>\sigma</math> is the risk associated with the investment.