Synergy’s 40-strong team will continue to operate out of Bristol and London under the name McCann Synergy, the company stated.
Synergy Creative was founded in 2006 by Gemma McGrattan, Giles Hicks and Nicky Clark. They will remain in the same roles as directors, reporting to Dean Lovett, chief executive of McCann Central.
Synergy Creative's clients have included Lidl, Aviva, Vodafone and Odeon.
Mark Lund, UK chief executive of McCann Worldgroup, which is part of Interpublic Group, said: “As we continue to go deeper and further in supporting clients to deliver best-in-class brand and customer experiences, we recognise the crucial role organisational culture and the employee experience plays in enabling it.
"Synergy was the clear partner for us to boost our offering to clients. Not only are they market leaders in the employee engagement sector, they’re a strategic and creative group with a deep passion for what they do, and we’re looking forward to growing together even further.”
McGrattan said: “As experts in an industry that continues to grow globally at a rapid pace, the opportunity to partner with McCann and share its global footprint is the perfect springboard to take us to the next level.”