In this paper we study the model risk of Expected Shortfall (ES), extending the results of Boucher et al. (2014) on model risk of Value-at-Risk (VaR). We propose a correction formula for ES based on passing three backtests. Our results show that for the DJIA index, the smallest corrections are required for the ES estimates built using GARCH models. Furthermore, the 2.5% ES requires smaller corr...