In a statement, Aegis Media North America CEO Sarah Fay said she and Sorokin "mutually agreed that he will leave his post at Carat." She added that he was "instrumental in creating the new Carat model of delivering integrated communications strategies," but offered no explicit explanation for his departure.
In his own statement, Sorokin said he was proud of his work at Carat, but said he is, "considering other opportunities focusing on digital marketing innovation."
Cass, meanwhile, assumes control of a slightly demoralized Carat U.S. operation, following an ignominious announcement last month that the agency would suffer a sizeable round of layoffs this year due to belt-tightening related to weak new business and client retention.
As executive vice president of Carat, Cass has overseen one of the agency's biggest clients, Procter & Gamble's global communication planning account. He has also served as head of communications planning for Carat in the U.S.