Sir Martin Sorrell’s S4 Capital ready to compete ‘at the highest levels’ after confirming Mightyhive takeover

Sir Martin Sorrell’s new company S4 Capital has completed a merger with US advertising group Mightyhive and is now “in a position to compete at the highest levels.”

The company announced the closing of the merger today and welcomed three new board members, Mightyhive principals Pete Kim and Chris Martin and Stanhope chief executive Daniel Pinto to the board.

S4 plans to integrate the US-based online advertising and marketing firm as part of its drive to form a new business combining media and technology.

It announced the $150m (£118m) earlier this month but today confirmed the merger and the admission of 8.9m ordinary shares to trading on the London Stock Exchange.

Sorrell said: “S4 Capital is now in a position to compete for comprehensive digital-first mandates at the highest level and is beginning to succeed meaningfully.”

The former WPP boss added that his new company was now “fully operational” in the areas digital content and programmatic media planning and buying.

Sorrell, who founded WPP, launched S4 Capital this year after leaving the advertising giant following an allegation of personal misconduct, which he has denied. Since then, he has been in close competition with his old company, including beating them in the race to buy Dutch digital agency Mediamonks for around €300m (£267m) in July.

Last month, S4 poached senior executive WPP executive, Michel de Rijk, as chief executive of its Asia-Pacific operations. It posted strong sales growth in the third quarter this year, delivering revenues of over €29m (£26.2m), a rise of almost 45 per cent.

The ad guru’s new business plans to bring together content, analytics and new technology to reach clients, based on a model which is focused on leveraging major tech platforms such as Twitter and Facebook.

Mightyhive specialises in programmatic advertising, and has worked with firms such as Opentable, Yamaha and Sephora.