The acquisition follows speculation last week that the Arnell Group had been in discussions with several potential buyers, including Omnicom and WPP Group.
Arnell was founded in 1980 by chairman and chief creative officer Peter Arnell, and specialises in youth and urban marketing, entertainment marketing, and multicultural marketing respectively. Arnell also offers corporate identity, design, and traditional and interactive advertising services.
The acquisition sees Arnell Group hopping almost from one advertising group to another. In May, Arnell bought back his firm from the Interpublic Group of Companies. Interpublic acquired a 55% stake in the consultancy last year.
John Wren, Omnicom group president and CEO, said, "Arnell Group gives Omnicom a significant competitive advantage in branded content and programming, which is what so many clients are seeking to complement their advertising, direct marketing and sales promotion activities."
The Arnell Group is based in New York and has around 120 staff and is best known for fashion work on clients including Esprit de Corp and Coca-Cola's Sprite brand.
br>Last week, DaimlerChrysler appointed Arnell Group to work with Chrysler's lead advertising agency, PentaMark, to develop marketing programmes. PentaMark is an Omnicom unit.