Asset management with an ESG mandate

We investigate the portfolio frontier and risk premia in equilibrium when institutional investors aim to minimize the tracking error variance and to attain a certain ESG score (ESG mandate). Provided that a negative ESG premium is priced by the market, we show that an ESG mandate can reduce the mean–variance inefficiency of the portfolio frontier when the asset manager targets a limited over-performance return with respect to the benchmark. In equilibrium, with mean–variance investors and asset managers endowed with an ESG mandate, a negative ESG premium arises if the mandate is binding for asset managers. The negative ESG premium is due to the ESG constraint (institutional investors over-invest in virtuous ESG stocks). We find empirical evidence of such a negative premium in the US market.