Mustier, a Frenchman, is due to unveil the bank's new 2020-2023 plan to investors on Dec. 3 in the British capital.
But with Prime Minister Boris Johnson vowing to pull Britain out of the European Union without a deal on Oct. 31 if Brussels refuses to renegotiate the terms of the divorce, Mustier was keen to show his European credentials.
"If we have a no deal Brexit, maybe we will have a financial communication in Milan because we want to remain in Europe. We are a very happy pan-European bank headquartered in Milan," he told reporters after the bank released first-half results.
(Reporting by Silvia Aloisi; Editing by Keith Weir)