Thanks both @topher and @RLX for sharing your thoughts. I wanted to pick up on a comment from @RLX about the Sharpe ratio, and how I tend to do it, which is slightly different.
So, I will try to explain my point using some examples I found online and I will use cars as I am a bit of a petrolhead .
Imagine we are comparing two rally cars. One of the drivers is fast but inconsistent, sprinting and slowing down unpredictably. The other driver is steadier, maintaining a consistent pace. If we were to look at their overall times, we might miss that one driver had a choppy drive while the other was more reliable.
The Sharpe Ratio is like judging those drivers and their cars purely by their overall speed relative to how erratic they were. It tells us how much return we got for every unit of risk we took on. However, sometimes, that might not be the whole story.
Now, let’s think about how we might prefer to watch a race. We might want to see how these runners would perform if they were running on the same track at the same pace. That is where the Modigliani-Modigliani (M2) measure comes in. It adjusts the race so both runners are running with the same level of risk (or volatility), and then shows us how much better (or worse) one did than the other.
The M2 measure translates everything into the same language and as a result provides an easier comparison. Returns are adjusted for a common risk level, making it super easy to compare our portfolio with a benchmark like the S&P 500 or FTSE 100, because it puts them on a level playing field.
Moreover, what we often want to know (I am speaking for myself at least): “Am I doing better than the market?” The M2 measure tells us this in a straightforward way. By adjusting our portfolio’s risk to match the market’s, it answers: “If my portfolio had the same risk as the market, how much would I have earned?” This is much closer to how I personally think about investment success.
Another interesting point is that the Sharpe Ratio might penalize a portfolio for having more volatility, even if that volatility comes with higher returns that we might be happy with. Conversely, The M2 measure shows how that risk translates into actual, tangible performance against the market, which in my case is what I care about.
I am getting there, I promise…the M2 measure can be seen as a better method because it converts abstract risk-adjusted performance into a simple return percentage, making it easier to see how our portfolio or single ETF stack up against the market. So in essence, the Sharpe Ratio is like judging a pizza by how cheesy it tastes compared to the amount of cheese used, which still gives us a score but perhaps not the whole picture. The M2 measure is like tasting two pizzas made with the same amount of cheese, and it directly shows which one is tastier.
I will provide some figures about one of the ETFs in the portfolio I posted to show what I am talking about.
Does this make sense at all? Please let me know and feel free to chip in. I am genuinely here to help as much as to learn!