ProPublica's study has found that since the Supreme Court ruling, Super PACs have seen not only a vast increase in big money donations, but also a skyrocketing in donations dominated by a single source. The group has found that in 2014, 59 Super PACs contributing a total of $113 million, or 16 percent of all Super PAC financing that year, were dominated by a single individual or group (to the tune of 80 percent or more). This amounts to over four times the $33 million such groups raised in 2012.
Faturechi and Stray argue that this worrying trend of political power being concentrated in the hands of the economic elite is only set to worsen in 2016, citing a recent report in the semi-monthly National Review, which noted that Texas Senator Ted Cruz's campaign for the Republican presidential nomination would be supported by at least four separate Super PACs, each of them controlled by a single donor.
The Super PAC system arising following the Supreme Court ruling on Citizens United in 2010 has been criticized by opponents of the overt fusion of big money with political influence ever since. Between 2011 and 2012, US political satirist Stephen Colbert won a Peabody Award for making an outright mockery of the Super PAC system with his "Americans for A Better Tomorrow, Tomorrow" Super PAC, pointing out the system's loopholes, and the fundamental threat the organizations pose to American democracy.
ProPublica's list of top single-donor PACs between 2012 and 2014 can be found here.