Martin Sorrell’s S4 Capital, a media investment company, agreed to buy San Francisco-based programmatic ad firm MightyHive for an enterprise value of $150 million, funded by the issue of new shares worth 74 million pounds ($94 million). Sorrell said the deal marked an important second strategic step for his new company. “The peanut has now morphed into a coconut, and is growing and ripening,” he said. Adding MightyHive’s programmatic capabilities to MediaMonk’s creative offer would enable S4 to offer clients fully integrated purely digital marketing, he said. The new capital raising is led by Stanhope Capital, which will be a long-term strategic partner, S4 said. Daniel Pinto, Stanhope Capital’s founder and chief executive, will join the board.