9. Irwin Jacobs (Co-founder and former chairman of Qualcomm)

Estimated worth: $1.4 billion 

Estimated donations: $627 million 

Charity: None 

He's also provided large contributions for education, engineering, hospital, and civil-liberty manners. His has given donations towards fellowships and scholarships for deserving students in the fields of engineering and computer science, as well as the arts. In 2010 he funded an engineering study on how to remove automobiles from the Plaza de Panama in San Diego's Balboa Park and agreed to chair a committee to study the proposal and develop private funding for it.

Irwin Jacobs has pledged $120 million for the San Diego Symphony, the largest ever to a symphony orchestra. In 2005 the Joan and Irwin Jacobs Center for La Jolla Playhouse was named after Jacobs and his wife in honor of their philanthropic contributions towards the institution's development.

In August 2010, Irwin and Joan Jacobs joined the Giving Pledge, pledging to give away most of their fortune to philanthropy.