James Murdoch, one of billionaire media mogul Rupert Murdoch’s sons, quietly invested $100 million into his nonprofit foundation, which then used a large chunk of the money to fund political groups during the 2020 election cycle.

CNBC found the enormous contribution from James Murdoch and his spouse, Kathryn Murdoch, after reviewing the 501c3 group’s 990 tax return from 2019, which the foundation provided. The Murdochs launched the foundation, called Quadrivium, in 2014.

The $100 million donation marks the couple’s largest known contribution to their foundation or any political effort. It came as James and Kathryn Murdoch were building their own political operation. They have largely backed nonpartisan and Democratic-leaning causes. Kathryn Murdoch has previously criticized former President Donald Trump for his handling of the coronavirus pandemic.

The Murdoch family, headed by Rupert Murdoch, is worth over $22 billion, according to Forbes. The family controls Fox Corp. and News Corp. James’ brother Lachlan Murdoch is the CEO of Fox, which has multiple assets including the conservative Fox News cable network.

It was previously known that James and Kathryn Murdoch backed President Joe Biden’s 2020 campaign. But it was unknown until now just how much they were spending behind the scenes to impact the election. Combined with the millions they gave to campaigns and political action committees, the $100 million donation would make the couple one of the top donors in the last election cycle.

The 2019 tax document shows that of the $100 million given to the foundation, over $25 million went toward grants, including for several political causes. The $25 million also represents the most the Murdoch couple has spent through their foundation on political causes such as fighting climate change and helping people vote.

Yet, according to a person close to the family, that $25 million two years ago was only part of massive Murdoch investments through the 2020 election cycle. This person declined to be named in order to speak freely about the situation.

Since 2019, Quadrivium directed over $43 million to climate-related groups. Over $38 million, including $14 million in Quadrivium donations and $24 million in individual contributions from the couple, went toward election organizations, including those dedicated to protecting voting rights.

The Murdoch couple also donated over $20 million to both Biden’s campaign, groups supporting him and opposing Trump, and organizations dedicated to disrupting online threats and extremism. They also donated to groups dedicated to getting out the vote during the Georgia Senate runoff elections in January. Democrats won both of those seats.

A spokeswoman for James and Kathryn Murdoch declined to comment.

According to the 2019 tax document, the Quadrivium foundation had more than $100 million on hand going into 2020, just as the primary and caucus season was beginning.

The Murdochs’ $100 million donation came the same year James was the CEO of 21s Century Fox before Disney bought the bulk of the company for $71 billion. He was also on the board of the family-owned News Corp. at the time.

The $100 million contribution to the foundation came in the form of Disney stock, and it was made the same day that the Fox-Disney deal was completed. James Murdoch made a reported $2.1 billion from the transaction.

Murdoch would later step down from the News Corp. board citing “disagreements over certain editorial content published by the Company’s news outlets and certain other strategic decisions.” News Corp. includes The New York Post and Dow Jones, which publishes The Wall Street Journal. Both newspapers have conservative opinion sections.

The Murdochs’ foundation in 2019 donated to several organizations it had supported in the past, although nonprofits received significantly more funds that year than other groups. Quadrivium supports issue-based groups that fight against climate change and try to improve access to voting.

The Murdochs’ support for voting rights groups comes as Republicans in states such as Georgia and Texas are passing laws that critics say restrict people ability to vote. James Murdoch was one of hundreds of executives and corporations that signed a public statement opposing “any discriminatorylegislation or measures that restrict or prevent any eligible voter from having an equal and fair opportunity to cast a ballot.”

Democracy Works Inc., a nonprofit that promotes itself as having tools to help people register to vote, received $2.5 million from the Murdoch-run foundation.

The education fund for Represent.Us, which claims to be nonpartisan and says it works to “pass powerful state and local laws that fix our broken elections and stop political bribery,” saw $2 million from the Murdochs in 2019. The group includes a cultural council of celebrities, including J.J. Abrams, Michael Douglas and Jennifer Lawrence. The Represent.Us fund, according to its website, “made grants to Represent.Us to support public education activities and dedicated cross-partisan outreach activities.”

The Brennan Center for Justice, which also calls itself nonpartisan, saw $1 million from the Murdochs two years ago. The Brennan Center has become a resource for voters and reporters to keep up on various bills that the organization deems restrictive. The group’s website notes that state legislatures have introduced over 380 bills in 48 states that are considered restrictive.

As for fighting climate change, Kathryn Murdoch has been a trustee at the Environmental Defense Fund for years. That organization saw $11 million in 2019 from Quadrivium.