CHICAGO — President Biden is spending a five-day vacation with his family at the $37 million estate of a billionaire donor whose appointment by Biden to a federal advisory board drew ethics concerns — with the White House describing the businessman as a “friend,” indicating he will stay for free.

Biden, 81, traveled to the Santa Ynez, Calif., ranch of Joe Kiani, CEO of medical technology company Masimo, after delivering an emotional, late-night farewell speech Monday at the Democratic National Convention.

Kiani, 59, poured cash into supporting Biden’s political campaigns and family foundation before scoring an appointment in September 2021 to the President’s Council of Advisors on Science and Technology, which advises the executive branch on policy areas involving Kiani’s business.

The 8,000-acre (12.5-square-mile) ranch features rolling hills, six bedrooms and a swimming pool.

First son Hunter Biden, 54, first daughter Ashley Biden, 43, their spouses and six of the president’s grandchildren accompanied the first couple on the trip.

An April 2022 letter by House Republicans to White House budget director Shalanda Young raised concerns about “the appearance that [Kiani] is benefiting from his political contributions.”

“Mr. Kiani is a prolific Democratic donor, contributing over $1 million to the Biden Foundation in 2017, $750,000 to the pro-Biden super PAC Unite the Country, and $1 million to the Biden Inaugural Committee,” said the letter signed by a dozen House Republicans, including organizer Rep. Ralph Norman (R-SC) and Oversight Committee Chairman James Comer (R-Ky.).

“In addition to receiving an appointment to PCAST, Mr. Kiani’s company Masimo has received nearly $3 million in federal government contracts since January 2021. Several agencies, including the U.S. Department of Defense, the U.S. Department of Health and Human Services, and the U.S. Department of Veterans Affairs have awarded contracts to Masimo.”

Masimo makes a variety of medical patient monitoring devices that measure blood oxygen saturation and pulse rate, as well as wearable watch-style health-tracking wristbands and home baby monitor cameras. The firm’s stock is traded on the Nasdaq and its annual revenue has topped $2 billion.

In addition to the advisory board appointment, Biden gave Kiani tickets to the December 2022 White House state dinner featuring French President Emmanuel Macron — granting him access to the gathering of trans-Atlantic business and cultural elites.

At a September 2023 event in San Francisco for the advisory board, Biden hailed Kiani for “finding and implementing solutions to reduce medical errors and other problems for patients’ experiences when hospitalized is going to improve health outcomes and protect our loved ones as well.”
 
“Joe Kiani knows a lot about that — been working with it a long, long time,” the president said.

Kiani’s net worth is estimated by Forbes to be $1.1 billion.

Biden has stayed for free at the homes of wealthy Democrats throughout his presidency — sparking concerns about the appearance of conflicts of interest and over the fact that he has neglected to list the vacations as gifts on annual disclosure forms, drawing parallels to Supreme Court Justice Clarence Thomas’ trips with billionaire Harlan Crow, who had no known business before the court.

“It’s the ethics double standard on display in all its glory as the last remaining days of Joe Biden’s grifting in public office come to a close,” said Mark Paoletta, the top lawyer at the White House budget office under former President Donald Trump.

“This donor ‘friend’ has been awarded millions in contracts by the Biden administration and is a Biden appointee. It’s open corruption in plain sight. And yet, Biden and his Democrat allies have the audacity to call for ethics reform at the Supreme Court. What a joke,” he added.

Paoletta, who is a personal friend of Thomas, said the latest vacation makes “at least 17 trips [as president and vice president] that ethics officials say Biden has unlawfully failed to disclose.”

ProPublic won a Pulitzer Prize in May for its reporting on Thomas’ vacations.

In at least one instance, Biden’s family stayed for free after asking for use of the home.

Biden has made two trips as president to the beachfront St. Croix home of Bill and Connie Neville, who also scored state dinner tickets — staying for free, even though the property typically is a paid VRBO rental.

He has stayed three times at the $38.9 million Nantucket compound of billionaire private equity leader David Rubenstein, presumably for free, and once for free at the $20 million Kiawah Island, SC, home of Maria Allwin, the widow of hedge fund founder James Allwin.

Biden spent a week last August at the $18 million Lake Tahoe mansion of billionaire environmental investor Tom Steyer. The White House claimed that vacation was paid for — prompting a short-lived local government investigation due to Steyer’s lack of a rental permit. The probe was called off without explanation.

Ethics experts have slammed Biden for not listing the trips on his annual disclosure forms.

“You can’t have the president just going around using people’s houses for free without disclosure. That’s no better than a Supreme Court justice staying on a yacht for free without disclosure,” Richard Painter, the top ethics lawyer in the George W. Bush White House, told The Post last year.

Kiani did not immediately offer comment, nor did the White House.