UniCredit declined to comment. It was not immediately possible to reach Passera for comment.

The bank's current chief executive, Federico Ghizzoni, has faced growing investor discontent with the bank's poor share price performance and stretched capital base. He agreed last month to step down when a successor is found.

Il Fatto said UniCredit would name Passera, who has also served as chief of the bank's biggest domestic rival Intesa Sanpaolo , on Friday, a day after Britain is due to vote on whether to remain a member of the European Union.

Sources close to UniCredit shareholders said the question of the new chief executive was still up in the air.

(Reporting by Isla Binnie, Gianluca Semeraro and Silvia Aloisi; Editing by Crispian Balmer)