Sortino ratio
Like Sharpe, but uses downside-only volatility in the denominator. Penalises losses without penalising upside moves. >2 is exceptional. Often a fairer measure than Sharpe.
The Sortino ratio is a way of looking at how much extra return you get for the extra risk you take on in an investment, but it focuses only on the downside risk. Imagine you're running a small business like a popular local snack shop in Lagos. You want to know how much profit you're making compared to the risks you're taking, but you only want to worry about the times you lose money, not the times you make money. The Sortino ratio helps you do just that by measuring the returns you get while considering only the days when you actually lose money.
In the Nigerian context, think about the Nigerian Exchange (NGX) where many retail investors buy shares. If you're investing in stocks, the Sortino ratio will tell you how much return you're getting for the bad days when the market dips, like when the Central Bank of Nigeria (CBN) raises the Monetary Policy Rate (MPR). Currently, the MPR is around 27.50%, which can make investors nervous. The Sortino ratio helps you understand your returns without being overly influenced by these bad days, which is particularly useful for Nigerian investors navigating the often volatile NGX.
To put it in a more relatable way, imagine you're putting your money in Treasury bills (T-bills) issued by the Nigerian government. If you want to know how well these T-bills are performing without worrying about the good days skewing your results, the Sortino ratio is your go-to metric. It's like having a personal financial coach who only focuses on the days you lose ₦ instead of all the days you make ₦.
When comparing different investments, a higher Sortino ratio is better. A ratio above 2 is generally considered exceptional because it means you're getting a lot of return for the downside risk you’re taking on. For Nigerian investors, this could mean choosing between different investment options like real estate, fixed deposits, or stocks, and the Sortino ratio helps you make that decision based on downside risk alone.
Why it matters: Understanding the Sortino ratio can help Nigerian retail investors make smarter decisions. By focusing on downside risk, it provides a clearer picture of what you're truly risking when you invest. This can be particularly useful in a market like Nigeria's, where economic conditions can change rapidly, making it essential to know how much you’re truly at risk of losing.