#7 Pierre and Pam OmidyarAmount donated in 2013: $225 million
Net worth: $8.5 billion
Beneficiary: Omidyar Network, Humanity United, Ulupono Initiative and HopeLab in Palo Alto, Calif.
Background: Pierre is an entrepreneur and philanthropist best known as the founder of online auction portal eBay. Pierre created eBay in 1995 and continues to serve as chairman of the board. Today, eBay enables more than 90 million buyers and sellers to connect and prosper over shared interests. His wife Pam is chairwoman of HopeLab, a Redwood City, Calif., nonprofit that develops technology to help critically ill children.