Now we know how much Mehmet Oz and David McCormick are personally spending on their Pa. Senate campaigns

It’s good to be a front-runner. Or just incredibly wealthy.

New financial reports filed Friday reveal in detail how Mehmet Oz and David McCormick, the leading Republican candidates in Pennsylvania’s U.S. Senate race, have spent a combined $18 million from their own personal fortunes to fuel their campaigns and make it the most expensive primary election in the country.

The reports, showing campaign finances through March 31, offer the first in-depth look at Oz’s campaign funding, and the first look of any kind at McCormick’s because he joined the race in January and didn’t have to file previous disclosures.

Their immense riches, and willingness to spend, will make it even harder for any of their rivals to catch them as the race enters an expensive homestretch before the May 17 primary.

Here are some key points the reports reveal:

The Republican race has been defined by the eye-popping wealth of Oz and McCormick.

The two candidates and their allies have already spent $33.8 million on TV through Sunday, with much more slated for the coming weeks, pushing most of their rivals into the background.

Oz’s report shows that the celebrity surgeon known as “Dr. Oz” has given his campaign more than $11 million since joining the race in November. That accounts for the vast majority of the $13.4 million his campaign has received overall. Of that, the campaign has spent $10.9 million.

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Oz raised $1.7 million from donors in the first three months of this year, the fourth most among all Pennsylvania Senate candidates. That was all before he won former President Donald Trump’s endorsement earlier this month, providing a potential boost in the closing weeks.

McCormick, who was until recently CEO of the world’s largest hedge fund, Bridgewater Associates, put almost $7 million of his own money into his campaign.

He also raised $4.3 million in his first three months in the race — the largest amount any candidate, Democrat or Republican, has raised in a single quarter. The haul largely came through top-dollar contributions from an array of friends and supporters in the world of banking and investing. (Along with McCormick’s hedge fund experience, his wife is a Goldman Sachs executive.)

But candidate spending is only part of the gusher of GOP cash.

McCormick has also been boosted by an astounding level of spending from independent super PACs backed by his wealthy friends and supporters. Two groups behind him had spent $13 million as of March 31.

The main one, Honor Pennsylvania, raised $15.3 million since forming in late December, more than any candidate or other PAC focused on the Pennsylvania race — including Fetterman, who has been in the race for more than a year and has been a fund-raising juggernaut.

» READ MORE: Mehmet Oz knows TV. Now his GOP opponents are turning Pennsylvania’s airwaves against him.

Close to half of the group’s money — $7.5 million — is from one fellow hedge fund leader: Kenneth Griffin of Citadel. And $1.25 million more came from Walter W. Buckley, the founder of the Bethlehem firm Buckley Muething Capital Management. Other donors routinely wrote six- and seven-figure checks to fund the barrage of attack ads that reshaped the race, helping McCormick cut down Oz’s initial lead and leave them as the two clear front-runners.

A new group attacking Oz, the Pennsylvania Conservative Fund, raised $3.5 million and spent $3.2 million of it. Almost all its money, $3 million, came from an entity called Defending America Together, for which there is little public information aside from a mailing address in Phoenix.

Super PACs can accept donations above the federal limits for donations to candidates, but by law they can’t coordinate with those campaigns. They also pay higher rates for TV time, making their spending less efficient.

Oz has his own super PAC, but is has much less financial power. The group, American Leadership Action, raised $3.1 million since forming late last year and has spent most all of that, leaving it with just $478,000 as of March 31.

The largest donors include Oz’s father-in-law, fellow heart-surgeon Gerald Lemole Sr., who gave $1 million, and former Morgan Stanley CEO John J. Mack, who gave $600,000.

Oz, citing reporting by The Inquirer, has criticized McCormick’s allies for taking money from donors he calls “never Trumpers” and Democratic supporters. But Mack in 2016 gave more than $130,000 combined to Hillary Clinton, the Democratic National Committee, and Democratic group American Bridge as they worked to defeat Trump. Mack has also given to Trump critics such as U.S. Rep. Liz Cheney (R., Wyo.) and donated $5,800 last year to his home-state senator, Majority Leader Chuck Schumer (D., N.Y.).

If Oz wins, his victory could cost Schumer his leadership of the Senate.

Oz and Mack have professional ties: Mack has sat on the board of New York Presbyterian Hospital, where Oz has been a cardiothoracic surgeon.

The GOP field has three ultra-wealthy candidates who moved back to Pennsylvania relatively recently, and their donations reflect that.

Of the money Oz raised from donors, the largest share, about 27%, came from Florida, where he owns a home in Palm Beach. He’s raised 19% within Pennsylvania, according to an Inquirer analysis.

Oz, who has lived for decades in North Jersey, has faced questions about his ties to Pennsylvania. He recently purchased a home in Montgomery County and, according to his campaign, had been living at his in-laws’ house in that county since late 2020.

» READ MORE: Does Mehmet Oz live in Pennsylvania?

McCormick — who grew up in Pennsylvania but lived for years in Connecticut before moving recently to Pittsburgh — collected about 24% of his donor money from Pennsylvania, the most of any single state, and 23% from New York. Still, he had the third-smallest share of donor money from within Pennsylvania among candidates in both parties.

Nearly all of the money for both candidates’ super PACs is coming from outside Pennsylvania.

Republican Carla Sands has the largest percentage of money coming from out of state. Sands, the former ambassador to Denmark, grew up in Pennsylvania but lived for years in Southern California. Almost half of her money from donors is from California.

With so much attention on Oz and McCormick, other Republicans found it hard to get traction.

Conservative commentator Kathy Barnette had the third-largest haul in the GOP, $346,000, far below the stratospheric totals for Oz and McCormick.

Her latest round of fund-raising was still more than the combined amount raised by Sands ($103,000) and Montgomery County real estate developer Jeff Bartos ($118,000).

Bartos had $2.4 million left in his campaign fund, having previously kicked in $1.2 million of his own money.

Sands, who previously led a major real estate investment company — yet is only the third-wealthiest Republican in the field — had $603,000 left in her campaign fund, after giving it $3.9 million, including $300,000 in the latest quarter.

Barnette had just $261,000 left.