White Castle represents the fourth Zimmerman Advertising client to launch a review in the past eight months.
The other clients were Office Max, Papa John's and Ashley Furniture. Ashley landed at McCann Erickson and Papa John's, at Grey, though Zimmerman still handles media responsibilities and creates franchisee and co-operative ads for the pizza chain. Office Max's review has just begun, with Zimmerman defending.
The Fort Lauderdale, Fla.-based agency also is defending the White Castle account, which includes creative and media responsibilities. The chain, which is based in Columbus, Ohio, spent about $9 million in media last year, up from more than $6 million in 2012, according to Kantar Media.
Rojek Consulting Group in Cleveland is managing the search, which is expected to conclude in early October.
"[White Castle] is a beloved challenger brand," said Lorraine Lockhart, president and founder of Rojek Consulting. "They seek an agency partner to align with their idea-rich, entrepreneurial culture and evolve the brand’s cultural relevance, especially among the millennial target."
Among the key decision makers is Kim Bartley, vp of marketing and menu development at White Castle.
Zimmerman, a unit of Omnicom Group, has handled the business since 2009. Before that, WPP Group's Team Detroit was White Castle's lead agency.