Warren Buffett has said he's willing to "put money" on Hillary Clinton winning the 2016 presidential race. Turns out, he really meant it.

The Oracle of Omaha gave the maximum donation allowed to Ready for Hillary last quarter, his first-ever check to the sort of independent political groups that he's scorned in the past. Buffett, who is the third richest man in the world, gave $25,000, the most any individual can donate under the committee's self-imposed cap, according to a person familiar with Ready for Hillary's post-election financial disclosure report. The group has raised more than $11 million to finance its efforts to lay the groundwork for a Clinton presidential campaign. Their latest report is due to be filed with the Federal Election Commission by midnight Thursday.

The contribution marks a major shift for one of the country's most famous business leaders, who's long been known in Democratic circles as a bit of a political tightwad. Though he's given hundreds of thousands to party committees and candidates, Buffett has shunned super-political action committees and other groups that can take unlimited sums. Last cycle, he headlined fundraisers for Obama’s re-election, though he rebuffed solicitations by Priorities USA Action, a super-PAC supporting the president. “I don’t want to see democracy go in that direction,” he said in May 2012 when asked at his company's annual shareholder meeting about his position on giving to outside groups. “You have to take a stand some place.”

Though he supported both Democratic candidates during the 2008 race, Buffett has long been an outspoken Clinton supporter, starting with his backing for her Senate campaign in 2000. Just days after President Barack Obama's re-election, Buffett told CNN that there wasn't anyone better qualified than Clinton for the job in 2016. He also said donating to super-PACs was simply "wrong,"  an opinion that he apparently no longer holds. "Hillary is going to win, yeah," he said at Fortune's Most Powerful Women Summit in October. "I will bet money on it. And I don't do that easily."

Other notable donors to the group, which operates in a similar fashion as a super-PAC, include Irene Hirano, the widow of late Hawaiian Senator Daniel Inouye; former New York Representative Ed Towns; and John Zaccaro, the widower of Geraldine Ferraro, the first woman to run on a major presidential ticket.