Sovereign ESG ratings from MSCI, Sustainalytics, and ISS diverge by more than two letter grades for 34% of the sovereign issuers we analysed. This is not a rounding error — it reflects fundamental methodological differences in how governance quality, social development, and environmental risk are weighted and measured.
Why the divergence matters
For EM fixed income managers, the choice of ESG rating provider is not neutral. A manager using MSCI ratings will have systematically different country allocations from one using Sustainalytics, even holding all other investment criteria constant. The directional effects are predictable: MSCI weights governance more heavily, which advantages developed-market institutions. Sustainalytics weights environmental vulnerability, which penalises low-income countries in climate-exposed regions.