December 10 (SeeNews) - Croatia's Hrvatski Telekom (HT) [ZSE:HT-R-A] and Zagrebacka Banka (ZABA) [ZSE:ZABA] have jointly hired Credit Suisse Deutschland to lead the process for the sale of their stakes in Zagreb-based Optima Telekom [ZSE:OPTE-R-A], HT said.