For the latest addition to its shareholder activism practice, Sidley Austin has brought on a lawyer from a locally headquartered shareholder relations advising firm that merged into a larger operation last year.

Derek Zaba, the former head of contested situations at advisory firm PJT Camberview Partners, joined Sidley Austin’s Palo Alto office on Monday as a partner in the firm’s global M&A and private equity group and co-leader of the shareholder activism practice. He is running the activism defense group together with Kai Liekefett, who joined Sidley Austin last year from Vinson & Elkins.