Among those outside spenders, dark money organizations -- 501(c)(4) and 501(c)(6) nonprofits that don't have to disclose their donors -- have nearly quintupled their spending of two years ago. These groups have already spent $2.5 million in the early months of the 2014 cycle, compared to just $440,678 at this point in 2012. The increases are only part of the story, though. There's also a leftward ideological shift taking place when it comes to who's spending the money.
Liberal Dark Money Dominating 2014 Elections - OpenSecrets Blog
