Wealthy individuals and the corporations they run account for $346 million of the amount raised by mega-donors. Unions donating $500,000 and more have given $75.2 million, and other groups like candidate committees, party committees, super PACs, PACs, non-profits and trade associations giving $500,000 or more have given $22.7 million.

Read full article: Sheldon Adelson Leads Super PAC Mega-Donors To Dominance In 2012