The infamous America Israel Public Affairs Committee, the most apparent face of the Zionist Lobby in the USA (and anywhere, excepting maybe the state of Israel) has declared (pdf) only two major donors, each one a person. One contributes $48.5 million and the other $13.5 million. All lesser contributors together add up to only $2.3 million.
Grant Smith deals with this issue at Global Research but he fails short of telling us who are those two super-donors, notably the main one, who, effectively control Zionism single-handedly.
I'm quite sure that it should not be too difficult to guess who are these two donors, however I will not pretend to know that as of yet (my knowledge of obscure Zionist conspirations and rankings in the Zionist mafia is admittedly very poor).