Frank & Forrest Mars
The Mars family owns the candy making company of the same name. At the death of Forrest Mars, Sr. he and his two sons were ranked the 29th, 30th, and 31st richest people in America. The family is extremely protective of their privacy and refuse to give press interviews or be photographed, with the exception of Jacqueline Mars.
Mars, Inc. is ranked as the 6th largest privately held company in the U.S. They make confectionary, let food, and other food products. They had $33 billion in annual sales in 2013.