WWE co-founder Linda McMahon was the third biggest backer of President-elect Donald Trump's White House bid. (Mike Segar/Reuters)

With his choice of restaurant executive Andrew Puzder to serve as his Labor secretary, President-elect Donald Trump has now tapped six big donors and fundraisers to serve in his administration, lining up an unprecedented concentration of wealthy backers for top posts.

Together with their families, Trump's nominees gave $11.6 million to support his presidential bid, his allied super PACs and the Republican National Committee, according to a Washington Post analysis of federal campaign filings.

One single appointee — WWE co-founder Linda McMahon — contributed $7.5 million to back his White House run before Trump selected her to run the Small Business Administration this week. She and her husband Vince were also the top outside donors to Trump's private foundation.

It’s not unusual for top presidential donors and bundlers to land plum assignments after an election. Ambassadorships to sought-after locales, such as London and Paris, are usually reserved for big money players. In recent administrations, senior campaign fundraisers have been chosen for Commerce secretary: Penny Pritzker under President Obama, Don Evans under President George W. Bush, Ronald Brown under President Bill Clinton, and Robert Mosbacher under President George H.W. Bush.

The Post's Matea Gold looks at how President-elect Donald Trump's campaign pledge to "drain the swamp" of special interests and big donors compares with his Cabinet picks so far. (Bastien Inzaurralde/The Washington Post)

But longtime watchers of money in politics cannot recall any president in recent history who has filled a Cabinet with so many major donors.

“In the past, they were a little hidden — they were sent overseas to be ambassadors,” said David Donnelly, president of Every Voice, an advocacy group that seeks to reduce the influence of wealthy donors on politics. “In this administration, they are going to be front and center making policy.”

Fred Wertheimer, president of the watchdog group Democracy 21, said Trump's choices raise questions about his pledge to “drain the swamp.”

“This is bound to result in all kinds of conflict and appearances of conflicts in terms of the financial interests of the people being appointed to high positions,” he said.

The president-elect's decision to put his major political backers in senior Cabinet positions is a jarring contrast with Trump's rhetoric through this year's campaign. He repeatedly declared himself independent of wealthy donors and predicted Democratic nominee Hillary Clinton's benefactors would “have total control over everything she does.”

“Donald Trump gave his Foundation's largest donor a CABINET spot yesterday,” Clinton adviser Ronald Klain tweeted Thursday. “Did you see blaring headlines? Imagine if HRC had done that??”

Trump transition officials did not respond to requests for comment.

The president-elect has defended the backgrounds of his Cabinet picks, saying he is choosing “killers” who know how to win. “I want people that made a fortune,” he told supporters at a rally in Des Moines Thursday night. “Because now they are negotiating with you, okay?”

Here's a breakdown of the donors Trump has nominated to serve in his administration and how much they gave:

Small Business administrator: Linda McMahon, $7.5 million

McMahon, co-founder of the professional wrestling franchise WWE and a former Republican Senate candidate from Connecticut, was the third biggest financial backer of Trump’s presidential bid, giving $7.5 million to pro-Trump super PACs, the RNC and his campaign. Between 2007 and 2009, she and her husband Vince gave $5 million to Trump's charitable foundation.

Education secretary: Betsy DeVos, $1.8 million (contributed by the DeVos family)

The Michigan billionaire philanthropist and her husband, Richard, whose father was the co-founder of Amway, are major conservative donors and GOP contributors. The couple gave nearly $317,000 to the Republican National Committee this cycle. Altogether, the DeVos family contributed a total of $1.8 million this cycle to the party and Trump's campaign.

Deputy Commerce secretary: Todd Ricketts, $1.3 million (contributed by his parents)

TD Ameritrade founder Joe Ricketts — the father of Todd, a co-owner of the Chicago Cubs — helped finance Future45, a super PAC that spent lavishly for Trump in the final weeks of the campaign. Joe Ricketts gave the group $1 million. He and his wife, Marlene, also contributed nearly $343,000 to support Trump's campaign and the Republican Party.

Treasury secretary: Steven Mnuchin, $425,000

Mnuchin served as Trump's national finance chairman, helping organize dozens of high-dollar campaign fundraisers across the country. The former Goldman Sachs executive and hedge fund manager also personally contributed $425,000 to the campaign and party.

Labor secretary: Andrew Puzder, $332,000

Puzder, who runs CKE Restaurants, the parent company of Hardee’s and Carl’s Jr., served on the Trump Victory committee as one of his top fundraisers in California. He and his wife together contributed $332,200.

Commerce secretary: Wilbur Ross, $200,000

The billionaire investor was an early financial supporter of Trump's campaign. Ross opened his Southampton, N.Y., estate for one of the campaign's first fundraisers, which cost $25,000 a head. Ross personally contributed $200,000.

It remains to be seen whether Trump will draw any other major contributors into his administration. New federal filings show his billionaire supporters poured millions more into pro-Trump super PACs in the final stretch of the race. His biggest supporters: casino magnate Sheldon Adelson and his wife, Miriam, who gave a total of $21.2 million to support his run. They were followed by Home Depot co-founder Bernard Marcus ($7.6 million), McMahon ($7.5 million), Dallas banker Andy Beal ($4.4 million) and hedge fund executive Robert Mercer ($3.4 million).

One of Mercer's daughters, Rebekah Mercer, is close to three of Trump's top advisers: Stephen K. Bannon, Kellyanne Conway and David Bossie. She and her father are expected to be major boosters of a new group Conway is likely to lead that will serve as an outside political operation to support his agenda.