Incumbent WPP first won the business in 2021, and formed a bespoke unit called WPP Open X dedicated to the beverage brand client.
After 23 years as part of IPG, the sale will return the creative innovation agency to independence as a privately owned company.
Lawson is promoted from global chief client officer.
Moves follow departures of Sue Higgs and Caroline Pay.
Spending related to the US election shored up ad revenue for YouTube which grew by 14% globally.
Toby Southgate had left Forsman & Bodenfors last October as global chief executive.
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