KES provides strategic consultancy through to sponsorship activation and only works for sponsors, not for rights owners. The agency, which was named Marketing magazine Sponsorship Agency of the Year in 2005, has clients including Aviva, British Airways, Coca-Cola, Guinness and RBS.
The deal is the third investment made by the group this year. It follows on from the acquisition of a majority stake in digital media consultancy Brand New Entertainment in October. Following the acquisition, the agency was rebranded as Huge Entertainment.
In July, the Engine Group acquired a majority stake in Eyefall (), the search engine optimisation and marketing agency.
According to Engine, which also owns Personal and Meme, this new acquisition continues to expand the group's breadth of marketing and consultancy services, which are designed to provide both standalone and integrated communications services.
Peter Scott, chief executive of Engine, said: "KES is an ideal business to be working alongside the Engine Group's partner companies. This will create tremendous synergies with several of our businesses in digital, public affairs, events and direct marketing."
Karen Earl, founder of KES, said: "As part of the Engine Group, we will be ideally placed to take advantage of sponsorship's appeal to an increasing number of clients."
Engine Group has experienced a number of restructuring changes this year with WCRS veteran Stephen Woodford quitting as its chief executive, having announced his departure to DDB in July.
Scott took over Woodford's role, while Robin Wight became the non-executive chairman.
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