From Open Secrets:
Twenty-four politically active nonprofits — including some of the biggest names in dark money — have devoted more than half their total spending to influencing elections in at least one year between 2008 and 2013, a Center for Responsive Politics analysis shows. At least three have done so more than once.
A new feature on OpenSecrets.org displays the percentage rankings. Because nonprofits file their annual tax returns, called Form 990s, long after the spending takes place, the data does not yet fully account for spending that took place in the 2014 midterms.
Most of the groups are 501(c)(4) organizations –– like public charities but organized under a section of the tax code that classifies them as “social welfare” nonprofits. That designation allows them to shield the identities of their donors from public view and to accept funds in any amount from almost any source. They can also spend unlimited amounts. Treasury Department and Internal Revenue Service regulations require that (c)(4) groups be “primarily operated” to promote social welfare, which, according to the IRS, means that their political activity must make up less than 50 percent of what they do.
As social welfare nonprofits, 18 of the groups — including Americans for Tax Reform, New Models and VoteVets.org in 2012 — spent millions of dollars on their own to influence candidates’ chances in elections just as super PACs or opposing campaigns might, but without revealing where they got their money. Some of the older groups, like Green Tech Action Fund in 2008 and West Virginia Conservative…