After more than 80 years in business and scores of iconic advertising campaigns, the Mithun name is being replaced.

Global marketing firm McCann Worldgroup announced Wednesday that it is consolidating its Twin Cities offices and rebranding them McCann Minneapolis.

McCann plans to reduce its staff by about 15 to 20 percent as a result of the move. Also, Mithun CEO Rob Buchner and Chief Creative Officer David Carter have decided to leave the firm as part of a "mutually done decision," said McCann spokesman Jeremy Miller.

Mithun's media planning subsidiary Compass Point Media and McCann's Minneapolis-based General Mills account team also will be part of the consolidated firm.

"The rebranding formalizes the closer working relationship between McCann and Mithun that has evolved in connection with growth and integration of the shared General Mills business," the statement said.

It further said: "We have enormous respect for the heritage and accomplishments of the Mithun agency. However, the opportunity to connect the Minneapolis operation more closely to McCann and our integrated disciplines is the best way to meet the needs of our clients in the region."

Known for years as Campbell Mithun, the agency — founded by advertising legend Ray Mithun and Ralph Campbell — has been in operation since 1933, making it one of the Twin Cities' oldest ad agencies.

The firm's clients have ranged from Land O'Lakes and Hamm's beer to, more recently, fried chicken fast food restaurant Popeyes and Mexican food chain Chipotle. In 2014, the firm simplified its agency name to just Mithun as it worked to reinvigorate its image.

Mithun became part of the advertising holding company Interpublic Group 20 years ago and began operating soon after as an independently branded North American unit within McCann Worldgroup.

Despite its legacy, Mithun has been challenged during the digital age, said Steven Wehrenberg, former Campbell Mithun CEO, who left the agency after more than 30 years to teach at the University of Minnesota.

"I think in today's competitive agency marketplace," he said, "an agency like [Mithun] was struggling to find its competitive positioning."

Clients have been more thrifty postrecession, wanting to pay less for advertising, have agencies assume more risk and even have them create content sometimes before getting paid, Wehrenberg said. Many of the agencies that are doing well are independent and don't have to worry about corporate overhead costs like those in a network.

Large, global clients like General Mills are looking for global advertising agency networks to work with, Wehrenberg said. In addition, McCann has offices across the world and it may have been difficult to manage an independent brand like Mithun.

"I think the marketplace, both employees and clients, were proud of the fact that we can have an agency that had that venerable history of doing super smart work for global brands. I think it's very, very sad," Wehrenberg said.

McCann Minneapolis will report to McCann Worldgroup President Luca Lindner. With the departures of Buchner and Carter, the agency will now be led by an executive board that includes John Campbell, McCann's executive vice president worldwide account director; Melissa Schoenke, Compass Point's managing director; and Scott Savarese, agency chief financial officer and director of North America financial operations at McCann Worldgroup.

Nicole Norfleet • 612-673-4495

Twitter: @nicolenorfleet