Layoffs have begun at Interpublic's Commonwealth/McCann in Detroit in the wake of the agency losing sizeable General Motors work. The agency gave notice to the state of Michigan that it would lay off 56 employees in a memo dated July 31.

The layoffs are anticipated to be permanent, the filing says. They will go into effect on Oct. 1.

A representative for Interpublic Group declined to comment on the layoffs, but they come after a June announcement that General Motors Co. would scale back work with the ad agency, long known for its work on the Chevrolet brand.

GM's agency overhaul, which was finalized on June 21, included moving Chevrolet creative from Commonwealth/McCann to Stagwell’s Anomaly, which has offices in New York and Los Angeles. Creative for GMC, Buick and Cadillac is being moved from Leo Burnett Detroit to agencies that do not have Detroit offices, including Austin, Texas-based Preacher, as well as Mother and 72andSunny, which both operate from the coasts.

Commonwealth/McCann currently employs about 450 people in its Detroit office. The layoffs are detailed in a so-called WARN notice to the state. The cuts appear to largely target creative roles at the agency, including seven of 12 creative directors at Commonwealth/McCann’s Detroit office. Two of the office’s four executive creative directors, its executive creative producer, three of five of its senior digital artists and more positions were included among the layoffs.

Commonwealth/McCann is expected to retain some work, including Chevrolet campaigns in several markets outside the U.S. The agency has handled Chevrolet since 2012, when Commonwealth was originally formed in March 2012 as a joint venture between Omnicom’s Goodby Silverstein & Partners and IPG’s McCann to handle Chevrolet. Goodby later split from the venture.

“IPG remains focused on delivering world-class creativity, capabilities and marketing effectiveness to General Motors and its brands across the many areas of the business that our agencies continue to serve, as well as to working with the partners being added as part of this agency model,” a spokesperson for IPG, said in a statement to Ad Age in June.

The GM agency overhaul sparked concern amongst metro Detroit creatives, and led to Southfield, Michigan-based ad agency Doner to pledge $1 million to hire talent in the Detroit area and manage a database of metro Detroit-based advertising talent. As of Thursday afternoon, 223 people have put their names in the database, a Doner representative told Ad Age.

Read more about Doner’s program

Anna Fifelski is a reporter for Crain's Detroit Business. Ad Age contributed to this report.