Because rapid growth tends to favor boutiques, we again looked at the fastest-growing larger PR firms, with revenues of more than $30m. UK firms, which were the three highest performers in the category on our 2017 list, are notably absent from this year’s top 10 — with two of them, Newgate and Hotwire, having recalibrated after major acquisitions. Japan’s Vector was the fastest-growing firm among this year’s biggest players, with fee incoming rising an impressive 38% to $146m – by far the biggest number registered by any firm on the list.

US firms, of which there were just two last year, rose up the ranks. Prosek Partners, which had the second-largest growth of the group, saw its fee income lift 32% to nearly $42m. Reflecting the hallmark year for midsize firms, the others are a diverse mix serving the breadth of industries —GCI Health, Marina Maher Communications, SKDKnickerbocker, Carmichael Lynch Relate, M Booth, W2O Group and Allison+Partners. Sweden’s H&H Group, in third spot, rounds out the group.