A small core of super-rich individuals is responsible for the record sums cascading into the coffers of super PACs for the 2016 elections, a dynamic that harks back to the financing of presidential campaigns in the Gilded Age. Close to half the money - 41 percent - raised by the groups by the end of February came from just 50 mega-donors and their relatives, according to a Washington Post analysis. Donors this cycle have given more than $607 million to 2,300 super PACs, which can accept unlimited contributions from individuals and corporations. That means super PAC money is on track to surpass the $828 million that the Center for Responsive Politics found was raised by such groups for the 2012 elections. The top 50 contributors together donated $248 million personally and through their privately held companies, or more than $4 out of every $10 raised by all super PACs. The last time political wealth was so concentrated was in 1896, when corporations and banking moguls helped McKinley, the Republican candidate, outspend Democratic rival William Jennings Bryan. Populist anger over how presidential races were financed led to a 1907 ban on corporations donating to federal campaigns. Forty years later, Congress prohibited unions and corporations from making independent expenditures in federal races. The picture dramatically changed in 2010, when the Supreme Court said in Citizens United v. Federal Election Commission that corporations and unions could spend unlimited sums on politics.