A good Sharpe ratio reflects attractive excess returns relative to return variability, but there is no universal number that makes a strategy safe or suitable. The ratio compares average excess return with its standard deviation over a defined period.
What does the number mean?
In a simplified annual illustration, 12% excess return divided by 12% volatility gives a Sharpe ratio of 1. A ratio of 2 means twice as much excess return per unit of volatility under the same measurement convention. These examples explain the scale; they are not promises or required targets.
Why context changes the interpretation
Comparisons require consistent sampling, annualization and benchmark assumptions. Fees should be treated consistently too. A ratio estimated from a brief favourable period has much less evidence behind it than one observed through varied conditions. Serial correlation and unusual return distributions also complicate interpretation.
A high ratio can coexist with rare large losses, concentrated exposure or a poorly tested model. Sharpe summarizes one aspect of a return series; it does not describe every risk.
AlphaNet displays Sharpe alongside other strategy information. The useful reading is comparative: consider return, drawdowns and track-record length together, rather than treating the largest displayed Sharpe as a complete verdict.