Jargon Buster


Sharpe Ratio

  • Investors should always be thinking about the risk-adjusted returns from individual assets (and their whole portfolio)
  • The Sharpe Ratio can be incredibly useful in comparing investments to determine if the risk premia that apply really are (or have been) worth taking on
  • Wealth managers will readily provide Sharpe Ratio calculations and you can look at the figures at either a very high level or really get granular, depending on your preferences

There are lots of metrics that we can use to understand the performance of our investments and one which you may hear your wealth managers frequently talk about, or see in reports, is the Sharpe ratio.

This eponymously named metric was developed by Nobel prize-winning American economist William F Sharpe back in the 1960s so that investors could better appreciate the risk-adjusted return on investments or, to put it more simply, whether the rewards (i.e. gains) from holding a particular asset merit the level of additional risk taken on in buying it.

The “additional” part is crucial here as the Sharpe ratio compares holding a risk asset like a stock to a relatively risk-free asset like a short-term government bond. This way, the investor can zero in on whether the additional risk was, in fact, worth it.

The Sharpe ratio is calculated by taking the risk-free rate of return away from that of the risk asset – or indeed a whole portfolio – and then dividing this figure by the standard deviation of that security or portfolio’s additional return (don’t worry, this calculation will be presented by a wealth manager to you in your investment reporting; you don’t have to crunch the numbers yourself). Typically, the higher the resulting figure, the more attractive the investment is.

You can use the Sharpe ratio to assess investments on a forward-looking basis using expected returns to help decide whether they are a good idea compared to something safer, or it can be used on a backwards-looking basis to unpack what exactly has driven your returns and whether too much risk has been taken to secure only a modest result, for instance. It is not, however, necessarily applicable to all investments as it relies heavily on volatility being a measure of risk, and the picture might be more complex than that for some elements of your portfolio.

You should not be intimidated by any of the metrics that might be applied to help assess potential (and actual) portfolio performance. While the calculation of the Sharpe ratio may slightly complex without specialist software which runs these numbers instantly, the bare numbers comparing one asset to another such as you would find in an investment report can be a very useful at-a-glance guide. In any case, your wealth management adviser will be happy to explain further what the parameters are that they are using and how your investments stack up against alternatives.

The Sharpe ratio is one of the most commonly used metrics for assessing risk-adjusted returns and it is always good to bear in mind as a reminder that investments need to be carefully calibrated to suit your risk profile and time horizon. If you would like to learn more about what sophisticated advice could do for your returns get in touch with our friendly team to learn more about your options. Or, if you already feel ready to start maximising your returns, take just a few minutes to carry out your wealth manager search today.