Natural Marketing Institute will continue to operate as an independent brand within the Research America group of companies following the merger, the terms of which were not disclosed.

Headquartered in Pennsylvania, Natural Marketing Institute was founded in 1990 and conducts consumer research specialising in health and sustainability. 

Research America’s agencies include Sigma Group, Repass & Partners and Viewpoint Consulting. The company has 14 offices and over 300 employees in the US.

Robert Porter, chief executive, Research America, said: "Research America and the Institute have been collaborative partners for the past few years. This announcement is a natural evolution of that strong alignment. By bringing together innovative leaders in market research and consumer insights and solutions, we are better positioned than ever to help business-to-business and consumer packaged goods marketers acquire, grow and retain customers."

Maryellen Molyneaux, managing partner at Natural Marketing Institute, said: "Our Institute team members will further complement RAI’s capabilities with the Institute’s, additional strategic consulting services, custom methodologies, syndicated databases and more."