Martin Sorrell beats WPP in $350 million takeover in his first acquisition since leaving ad giant

Sir Martin Sorrell has completed his first acquisition since leaving advertising agency conglomerate WPP in April.

His new venture, S4 Capital, has bought Dutch digital production company MediaMonks in a deal reported to be valued at 300 million euros ($352 million).

Other bidders were WPP and Accenture Interactive, according to a Financial Times report.

MediaMonks has revenues of around 110 million euros, with 11 offices and 750 staff, according to a statement emailed to CNBC on Tuesday. It was founded in 2001 and its clients include Amazon, Google, Johnson & Johnson and Netflix.

The acquisition comes amid WPP claims that Sorrell has breached confidentiality clauses in his contract, which he denies, with Chairman Roberto Quarta trying to prevent him from getting a £20 million exit payout. Sorrell left WPP abruptly in April amid allegations of personal misconduct, which he also denies. He has since said leaving the firm was like being “hit by the bus.”

MediaMonks produces digital content, including ad campaigns, short films, web content and apps, and Sorrell said the company would add data analytics and media buying to its services.

“With this merger, I’m privileged to be shaping the future of the creative industry alongside a man with an unprecedented reputation for building successful businesses. We’re not selling out, we’re buying in,” MediaMonks’ CEO Victor Knaap said in an emailed statement.

Sorrell, who is listed as the company’s “Senior Monk,” added: “We're delighted to join forces with MediaMonks. This represents a significant step in building a new age, new era, digital agency platform for clients. MediaMonks' roots are totally in new media, and data, content and technology. Our next moves will be to build this platform further and to add meaningful data analytics and digital media buying. The company will be a unitary one with MediaMonks as its core.”

MediaMonks’ work includes a 360-degree video for luxury Dubai hotel the Burj Al Arab, an interactive Ikea catalog and a Nestle app to encourage children to drink more water.