Hacked emails contain documents revealing hundreds of donors to the Center for American Progress and Media Matters for America, liberal nonprofits that have resisted efforts to disclose their funders.
Most of the emails were sent to CAP founder John Podesta by Mary Pat Bonner, a prominent Democratic fundraiser who has worked for both groups to raise money from the wealthiest donors on the Democratic side of the aisle.
Others were sent to Podesta in his capacity as a member of CAP's board. He led the think tank from its founding in 2003 until he joined the White House in 2014. Since leaving that post to chair Hillary Clinton's presidential campaign, he has rejoined CAP's board of directors.
CAP's general counsel attached a copy of its annual tax filing for 2014 in an email to CAP's board in August 2015. Though 501(c)(3) "social welfare" nonprofits such as CAP are required to disclose their top donors to the IRS in that annual filing, they are not required to make that information public.
"Please note that Schedule B, listing contributors to CAP, is not redacted in the attached, and should be kept confidential," the email advised.
The email was one of thousands released by the group Wikileaks after hackers believed to be acting in concert with the Russian government breached Podesta's email account.
The unredacted filing lists nine donors, all of which are charitable foundations, that together gave CAP more than $23 million in 2014. They represent all donors that gave more than two percent of its total contributions for that year, the threshold for schedule B reporting.
The contributions include $7 million from a foundation run by controversial banker Herb Sandler, who later hired Podesta as a consultant; $1.6 million from billionaire Democrat Tom Steyer's TomKat Foundation; and $1 million from the Sea Change Foundation, led by Bay Area financier and green energy investor Nat Simons.
Another table in the tax filing lists running tallies of major donors to the group for the purposes of calculating "excess contributions," or contributions that have exceeded the two percent threshold, over five years.
Donors on that list also include the Sandler Foundation, which is listed as a $24.4 million donor. The Wyss Foundation, a group run by Swiss billionaire Hansjorg Wyss, has given $17.4 million. Insurance magnate Peter Lewis has donated $8.3 million personally. Steyer's TomKat and George Soros' Open Society Foundation have each given $5.1 million.
CAP began publicly posting lists of its corporate and foundation donors on its website in 2014. However, due to the lack of legal disclosure requirements, it is impossible to know whether those lists, which did not include individual donors, were accurate or complete.
Steyer, Sandler, and Simons all appear on lists of individual donors sent to Podesta by Bonner since 2008. In various spreadsheets and one-off notes, Bonner revealed the names of 224 CAP contributors, and in many cases a general range of their support.
Bonner has fundraised for CAP for years. Another of her clients is Media Matters. In additional emails to Podesta, she revealed the names of 91 donors to that group, which is even more resistant to donor disclosure than CAP.
A spreadsheet of donors to both groups can be found here.
Though some of the donations listed in Bonner's emails are nearly a decade old, they provide the most complete accounting to date of contributors to both groups.
A CAP spokeswoman declined to comment on the hacked donor information. Media Matters did not respond to a request for comment.