Sir Martin Sorrell has been an expert on M&A for almost half a century. He founded WPP through reverse acquisition in 1985, and built it up into a towering ad giant that snapped up major agency brands like J. Walter Thompson, Ogilvy & Mather, and Young & Rubicam.
Following an ignominious departure in 2018—WPP accused him of misusing company assets—Sorrell plotted a comeback, founding S4 Capital just weeks later.
S4 built itself up through acquisition, notably production agency MediaMonks and performance agency MightyHive, positioning itself as a digital-first holdco. Lately, that thesis has been severely tested as many tech clients, where S4 has heavy exposure, pulled back on marketing spend to invest in AI.
Revenue contracted, and shares fell about 38% over the course of last year, though its early 2026 results have indicated improvement. S4 currently views itself as being in a period of stabilizing its business before revisiting growth-by-acquisition.
ADWEEK sat down with Sorrell to get his read on the market, who should buy whom, his competitors (whom he’s never been shy to criticize), and S4’s next steps.
This interview has been edited for length and clarity. It was conducted before Publicis said it would buy LiveRamp, and Accenture said it would buy Whalar.
ADWEEK: The ad agency holdcos have gone from the biggest industry acquirers to acquisition targets. What’s the outlook?
SIR MARTIN SORRELL: There are very few, if any, exits. No activists have stepped in. There are no takers. Most of the big deals would involve syndicates. One PE firm couldn’t write the check for WPP or Dentsu. Maybe Bain Capital could have done it on their own.
Besides Publicis, is any big holdco a buyer at this point?
Omnicom probably isn’t. Dentsu is not going to be in buying mode. Stagwell will try. The irony may be, this is the time to take the risk because valuations are so battered. But I don’t think people would take a risk.
If anyone was going to take a risk, who do you think it would be?
Well, Havas. Maybe not of scale. But [Havas CEO Yannick] Bolloré always sends you in the wrong direction. Always. Keeps you guessing.
And I think Accenture. If I was [Accenture CEO] Julia [Sweet], I would go for WPP. With them, they could get significantly better. I think the media piece in their hands would be very valuable. But whether they’ve got the balls though… It would be messy. But you’ve got David Droga there.
