Colin Kinsella, CEO at Mindshare, North America, is leaving the GroupM media agency and being replaced by Ernie Simon, president of GroupM Consulting.
It's not clear if Kinsella has another job lined up; Mindshare wouldn't comment.
The agency also said Adam Gerhart, Mindshare's West Coast lead, was promoted to CEO for the U.S., and Cindy Gustafson, managing director of the agency's Invention Studio in North America, was named chief strategy officer in the U.S.
Gerhart's role is new at Mindshare, while Gustafson replaces Jordan Bitterman, who was chief strategy officer, North America, and is departing the agency.
Both Kinsella and Bitterman joined the WPP network from Publicis Groupe where Kinsella had been CEO of Digitas, North America, and Bitterman was head of social, mobile and content at Digitas. Kinsella has been the North American chief at Mindshare for less than three years, replacing Antony Young, who had the job for 22 months, in 2013.
At GroupM Consulting, Simon worked across the group on new and existing business to sell clients on the range of GroupM's and WPP's resources. He launched the consulting practice in 2013, joining Mindshare from OMD where he had been chief strategy officer. Simon previously had more than 10 years' experience at GroupM, seven of which he spent as part of the Mindshare team, first as global strategic planner and later as chief strategy officer, North America.
Mindshare said a search is on to find a replacement for Simon at GroupM Consulting.
Before leading Mindshare's West Coast operations, Gerhart, as an agency managing partner based in London, helped lead growth with multinational clients including Nestlé and BP.
At Invention Studio, Gustafson launched the new division to develop original ideas that "weave brands into culture by using media as creative," the agency said. She previously led business for Mindshare clients like Unilever and American Express.