LONDON (Reuters) - Martin Sorrell's new advertising vehicle S4 Capital has acquired an influencer marketing company, IMA, for 10 million euros (£9.31 million), combining it with its content arm MediaMonks to bolster production output.

Founded in 2010, IMA and its 85 staff select people on social media with large followings, known as influencers, to create tailored online campaigns for brands including Pernod Ricard, Under Armour, Heineken and Samsonite.

Sorrell established S4 Capital in 2018 after he left WPP , the world's biggest advertising agency, following a complaint about misconduct which he denied. It is designed to deliver digital advertising and marketing quickly for clients.

"This merger is yet another example of our focus on top line growth," Sorrell said. "Influencer marketing is an important sub-set of the digital content marketing industry and is predicted to double in size over the next three years."

(Reporting by Kate Holton, Editing by Paul Sandle)