Isobar, Aegis Group's global digital network, said it has acquired Ammo Marketing, a word-of-mouth marketing agency - Isobar's third acquisition in the U.S. in the past 15 months. Terms of the agreement were not disclosed. Ammo was founded in 1999; its current clients include Volvo, Cadbury Schweppes, Remy-Cointreau, Miller Brewing and Brown-Forman. The Isobar U.S. network includes Freestyle Interactive, Carat Fusion, iProspect and web shop Molecular.

Ammo's Julian Aldridge will become president of both Freestyle and Ammo; partners Kerry Lange and Andrew Strickman will retain their roles managing the growth and clients of Ammo.

"Word-of-mouth marketing truly will be the next big battleground for marketers who understand that with key Peer Influencers you can reach hundreds of people in a very significant way," David Verklin, chief executive of Aegis Media America and Asia, said in a statement.

"What Isobar gives us is the opportunity to continue to expand our service offerings to our clients both in the U.S. and internationally. Even though 90 percent of Influencer conversations are offline, the digital medium is becoming an increasingly critical communication channel, both online and through mobile," Aldridge is quoted as having said.