Should new prudential regulation discriminate green credit risk ? A macrofinancial study for the Output Floor case

Differentiated treatment of green credit risk in banks’ capital requirements to favor green transition generates lot of debates among European prudential regulators. The aim of this paper is to examine whether the key Basel 3 finalization instrument - the Output Floor - should be applied to green credit risk in order to ensure stability of banking system and promote green finance. To do so, we assess macrofinancial and environmental benefits of such green policy for the Euro Area through the lens of a general equilibrium model. We get three main results. First, when banks get transitory ’environmental awareness’, an Output Floor (OF) applied to brown credits only (i.e. a brown OF) faces a trade-off between limiting environmental aftermaths and reaching OF objectives (i.e reducing volatility of banks’ capital adequacy ratio). Second, to mitigate the prudential cost of this trade-off, brown OF should be joined with additional green financial policies such as green Quantitative Easing. Third, pollutant emissions tax erodes brown OF efficiency along financial and economic cycles but limits the welfare cost implied by pollution in the long run.