James Simons: $7 million
Mathematician James Simons founded Renaissance Technologies, the same Long Island hedge fund that made the fortune of conservative donor Robert Mercer. Renaissance Technologies lobbies Congress on tax issues affecting hedge funds; it spent $460,000 in 2015 on a pair of K Street firms. In the wake of the 2008 financial crisis, Simons argued against greater regulation of hedge funds before Congress. Simons, who's worth of $15.5 billion, and his wife Marilyn have given $33.7 million to federal candidates and committees since 2003.
Fred Eychaner: $5 million
Fred Eychaner has made his fortune with his company Newsweb, which publishes alternative and ethnic newspapers and owns television and radio stations in Illinois and Indiana. Newsweb has never registered to lobby in Washington, but Eychaner has given $42.8 million since 2003 to party committees, candidates and outside spending groups. Eychaner is a major supporter of marriage equality, LGBT rights and AIDS prevention and awareness, and supports them through his Alphawood Foundation. The Clinton Foundation is among the charitable organizations he supports. He's given it more than $25 million.