In recent years, bondholders have encountered a changing investment landscape that increasingly emphasises sustainability. This article discusses how we apply Fidelity Optimus, our award-winning platform, to respond to client needs in high yield multifactor strategies. Governments worldwide, including the EU, are implementing more stringent policies on carbon emissions to better align with the goals of the Paris Agreement. As a result, more portfolios aim to limit average global temperature rise below 2°C and ideally 1.5°C relative to pre-industrial levels.