Treasury Secretary Steven Mnuchin was a Goldman Sachs banker before joining Donald Trump's administration. Here's what you need to know about him. (Deirdra O'Regan/The Washington Post)

The three latest nominees tapped by President-elect Donald Trump were major financial backers of his White House campaign.

Their selection deepens the role that wealthy donors are playing in shaping the new administration, despite Trump's oft-repeated pledge to “drain the swamp” of special interests.

Steven Mnuchin, Trump's pick for treasury secretary, served as his national finance chairman, helping organize dozens of high-dollar campaign fundraisers held across the country. The former Goldman Sachs executive and hedge fund manager also personally contributed at least $425,000 to support Trump’s presidential bid, through donations to the campaign, the Republican National Committee and state parties, according to Federal Election Commission data.

Billionaire investor Wilbur Ross, who Trump selected as his commerce secretary, was an early financial supporter of Trump's campaign. He opened his Southampton, N.Y., estate for one of the campaign's first fundraisers, which cost $25,000 a head. Ross personally contributed at least $200,000 to support Trump's run, finance records show.

Wilbur Ross is President Trump's new commerce secretary. Here's what you need to know about the billionaire investor. (Monica Akhtar,Osman Malik,Thomas Johnson/The Washington Post)

Trump selected Chicago Cubs co-owner Todd Ricketts to serve as deputy commerce secretary. His father helped finance Future45, a super PAC that spent lavishly for Trump in the final weeks of the campaign. TD Ameritrade founder Joe Ricketts gave the group at least $1 million through the end of September, FEC filings show. Joe Ricketts and his wife, Marlene, also contributed nearly $344,000 to support Trump's campaign and the Republican Party.

The Ricketts' financial support for Trump was a dramatic reversal from the primaries, when Joe and Marlene Ricketts gave more than $5.5 million to Our Principles PAC, a super PAC that ran a slew of hard-hitting ads against Trump. Their financial backing for the group prompted Trump to threaten to expose secrets about the family, which owns the Chicago Cubs, tweeting that they “better be careful, they have a lot to hide!”

On Wednesday, Trump praised Todd Ricketts as “an immensely successful businessman.”

“The incredible job he and the Ricketts family did in the purchase and turnaround of the Chicago Cubs — one perfect step after another, leading to the World Championship, is what I want representing our people,” the president-elect said in a statement. “I am very proud to have him on our team.”