Besides Koerner, who spent over a decade at UBS before returning to Credit Suisse in 2021, UBS CEO Sergio Ermotti largely leaned on UBS executives in pulling together his new team.
Commenting on Koerner's future role, UBS said Koerner would be responsible for Credit Suisse's operational continuity and client focus, while supporting its integration.
Credit Suisse executive board members will report to both their relevant UBS executive board member and Koerner.
Reuters reported last week that options under consideration for that business include a sale or an initial public offering of Credit Suisse's domestic unit.
“This is a pivotal moment for UBS, Credit Suisse and the entire banking industry," Ermotti said in the statement.