Shareholder activism worked in 2025. The surge will continue this year.

A notable development in activist M&A initiatives last year was the teaming up of activists with private-equity firms and traditional fund managers, Rossman said. After Corvex Management disclosed its 4.9% position in the recruiting firm Heidrick & Struggles, the recruiter agreed to an October buyout by Corvex’s private equity unit and Advent International. In December, mutual fund manager Janus Henderson agreed to be bought by General Catalyst, after a Trian Partners campaign resulted in the departure of Janus’ CEO.