This is according to research from Results International, a provider of finance advice to various sectors. The firm's results are based upon all corporate data in the public domain, and tracks all deals where more than 40 per cent of shares in an entity are traded.
The research recorded 75 PR M&A deals globally in 2015, one fewer than in 2014.
In two fifths (31) of those deals, the firm being acquired was North American – a slight drop from the 33 North American firms acquired in 2014, Results found.
There were no major shifts in regional trends; 19 UK firms were acquired (18 in 2014), nine acquisitions were made in Western Europe (10 in 2014) and 10 in APAC (11 in 2014).
2014's most acquisitive agency was Toronto Stock Exchange-listed MDC Partners. The biggest buyers this year were US firms Finn Partners and Teneo Holdings, with three each. Of 2014's 76 acquisitions, 52 were made by firms that only made a single acquisition in the year – the same is true for 59 of 2015's 75 acquisitions.
Results managing partner Keith Hunt commented that tech-enabled and specialist agencies "remained highly prized assets as the traditional PR world expands across social, content and technology".
He also said: "Private equity interest in the sector remains relatively quiet, with three deals in 2015 compared to five deals in 2014. As always, PR is one of the more challenging areas for PE investment with a few scaled exceptions in the UK including Four Communications and Instinctif Partners alongside US acquirers."
Across the marcoms sector as a whole, Results found there were 979 deals globally in 2015. PR companies were the third-biggest target; there were 101 of full-service digital firms and 76 of digital agencies. The biggest buyers were WPP (38 deals), Dentsu Aegis (36), Publicis (21) and Havas (seven).
Note: this story was corrected after publication. It initially said Ruder Finn Group was the most acquisitive agency in 2015 with four acquisitions. The report authors had arrived at that figure by erroneously counting three acquisitions made by Finn Partners and the one acquisition made by Ruder Finn Group together. In fact, Finn Partners separated from Ruder Finn Group in 2014.