The argument we often hear is that by only investing sustainably you are closing down potential sources of return. This is true. In reality it’s impossible to invest without some sort of constraint. Simply put, the time and resources required to keep track of everything that it’s possible to invest in are too great, and most investors naturally apply some constraints. But surely it all comes down to the type of constraint and whether that’s viewed as a risk management measure or as an opportunity enhancer? Our paper explores this through the lens of our investment philosophy.