Publicis said the move, which will unite Saatchi & Saatchi and Fallon in a new alliance, will keep the agencies as separate and standalone brands. It will operate under the leadership of Kevin Roberts, Saatchi & Saatchi Worldwide chief executive.
As part of the formation of the SSF Group, Fallon will become chairman emeritus of Fallon Worldwide. Fallon will step down from day-to-day affairs but will continue to advise on the group's direction, while Fallon's Minneapolis headquarters will now report to the SSF Group.
Publicis also confirmed a number of appointments; Robert Senior, one of the founding partners of Fallon London, will become CEO for the SSF Group in the UK, and report to Roberts.
Simon Francis, previously EMEA managing director at media buying network OMD, will replace Jim O'Mahony as Saatchi's EMEA chief executive.
O'Mahony has been appointed CEO of the China, Russia, India and Brazil regions. O'Mahony and Francis will each report to Roberts.
Maurice Levy, Publicis Groupe chairman and CEO, said the new group would enable Saatchi & Saatchi and Fallon "to maximise the potential of their creative resources at a global level".
He said: "With this alliance, the Fallon network is entering into a new exciting phase of its history. Under Kevin Roberts, Saatchi & Saatchi is recording unprecedented growth and is now one of the fastest growing and most creative networks in the world. I am confident that the new structure will usher in a new era of powerful growth for Fallon and Saatchi & Saatchi."
Fallon said: "A closer relationship between the two agencies will help our growth, provide development opportunities for our people, and ensure a bright future for Fallon as a standalone brand, while continuing to deliver the best to our clients."