More than two dozen M&A deals have taken place between US PR firms since the beginning of the year, with more than half of those occurring from June on. These include high-profile deals such as Next Fifteen's August purchase of M Booth and Associates to this week's merger of two Las Vegas agencies.

As expected, the number of deals is much lower than M&A activity in boom years such as 1999 when PRWeek reported more than 80 US deals, and at least ...