How important is the dispersion of ratings?
In the space of just a few years, ESG metrics have established themselves as an essential third pillar of financial analysis in the construction of investment strategies, complementing return and risk. The notion of “conviction” with regard to ESG criteria is no longer important, as institutional investors must respond both to the demands of their clients and to the constraints of current and future regulations.
The integration of ESG data into models, analyses and strategies is thus reshuffling the cards of a well-established system, the urgency of which is accentuated by a heightened competitive context. Although necessarily incorporated in the same way as other portfolio management indicators , their use may nevertheless call for some very specific considerations.
This contribution addresses the problem of the dispersion of ESG ratings around the average rating of an investment portfolio, first with a detailed intuitive approach, then illustrating the evolution of this phenomenon using clustering algorithms and transition matrices linked to Markov chains, and finally proposing possible solutions for integrating this bias into portfolio monitoring indicators.
Under no circumstances will this contribution be able to determine which ESG rating allocation structure should be considered optimal for the investor; rather, its aim is to highlight the importance to be attached to this structure.
