Interpublic Group’s UM previously handled media planning and buying in Europe, while the business was with Publicis Groupe Starcom MediaVest Group in Microsoft's largest market, the US.
Media planning will now be handled by a cross-discipline team from Dentsu Aegis agencies, lead by its agency Carat.
Although IPG has lost the media business, its creative agencies have won the advertising business. Creative work and deployment will be handled by various agency teams throughout its global network, led by McCann Worldgroup.
The creative advertising account was held by various agencies, including MDC’s Crispin Porter & Bogusky, which was one of Microsoft’s lead creative agencies globally.
Chris Capossela, the executive vice president and chief marketing officer at Microsoft, said: "We are thrilled to work with the teams at IPG and Dentsu Aegis. We believe both groups will help us communicate more strategically and efficiently in a rapidly evolving marketplace."
In statement confirming the appointments the company said: "Microsoft periodically evaluates its agency mix as a best practice to ensure it retains the services that best fit the needs of its evolving business."