Mahony, who had been with Edelman for four years, was previously head of comms at Sapient and has worked on financial comms for brewer Ambev.
McBride was corporate affairs executive at Bank of America's asset management group before joining Edelman in 2000. Donsky joined the agency in the same year from Morgan-Walke, where he was a director and senior V-P.
Edelman financial comms and IR global MD Andrew Merrill insisted the agency would not lose clients as a result of the departures and that Mahony's former position could be scrapped.
He said the firm would 'add senior talent'.