Matty Tong is believed to have left the agency, having only been appointed as strategic planning director in October 2009.
Tong was part of the firm's European management team, reporting to UK and European CEO Colin Byrne, and joined from global advertising group Lowe Worldwide.
The details of the other two redundancies are unknown, but are understood to be in the London office. Tong could not be reached for comment and Weber Shandwick refused to comment.
