UPDATE 1-Ad man Sorrell eyes roaring recovery, more deals

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LONDON, March 16 (Reuters) - Martin Sorrell, the world's most famous advertising executive, expects global economies to roar back to life as they recover from the pandemic over the next two years, but is worried about what comes after that.

"The drum beat in our daily meetings is getting louder and louder and louder, things are flying," the executive chairman of digital advertising company S4 Capital SFOR.L told Reuters, adding the tech and healthcare sectors were leading the charge.

He said he expected his firm to be at the "north end" of the market's estimates of 15 to 20% like-for-like gross profit growth for last year, and is eyeing more deals, including a small content one.

He also said that ideally S4 would one day agree a transformational deal where it inserts itself into a bigger company that is then run together. He suggested the digital transformation company Globant GLOB.N as an ideal partner.

The almost three-year-old S4 counts Google, Facebook and another undisclosed global tech firm as clients and is purely focused on digital advertising, which has continued to grow in the pandemic and now accounts for more than half of ad spend.

"I think we're a royalty on the growth of digital transformation," Sorrell said. "We will be at the north end of the market's estimates of 15 to 20% like-for-like growth during COVID," he said.

He said he was "extremely bullish" about 2021 and 2022 as consumers and companies resume spending, but longer term he is worried about soaring government debt.

"The consumer has been saving like crazy, and I think companies have been saving like crazy and I think they're going to open the spigots in Q2," he said.

"It'll be great for '21 and '22, but then how do we figure out who's going to pay for this?"

(Reporting by Paul Sandle and Kate Holton. Editing by Louise Heavens and Mark Potter)

((kate.holton@thomsonreuters.com; 0044 207 542 8560; Reuters Messaging: kate.holton.thomsonreuters.com@reuters.net))