The Dentsu Aegis shop has been tasked with developing a digital platform for Western Union’s campaign around Chain of Betters.
The pitches took place in February and there was no intermediary involved.
In November last year it began a campaign to "kick-start a chain of selfless good deeds around the world" by donating $1,000 for project ideas.
Mcgarrybowen handles above the line work for Western Union. In 2012 the company had worked with 180 Amsterdam to create a global campaign featuring Patrick Vieira, the former Arsenal footballer.
Muriel Lotto, the vice president for global marketing strategy and brand management at Western Union, said: "Isobar’s strong strategic thinking and collaborative culture, combined with its digital capabilities, will be key to helping us evolve the Chain of Betters programme."