Mannatech Incorporated, Coppell, TX, has appointed three veteran company executives to the newly created Senior Executive Office, following the resignation of president and CEO Wayne Badovinus. Steve Fenstermacher, CFO, and Rob Sinnott, chief science officer, have been named co-CEOs, while Randy Bancino, senior vice president, has been named president of global business operations and expansion. Top management responsibilities will be shared between these three officers.