If Donald Trump really is auditioning Newt Gingrich for a role in his administration, one job Trump should definitely give to someone else is Treasury secretary. Although Gingrich has long been a deficit hawk when it comes to the country’s balance sheet, several of Gingrich’s own organizations have ended mired in debt.

The most recent is Gingrich’s own presidential campaign, Newt 2012, which continues to owe millions of dollars to former staff, vendors, and even Gingrich himself. Gingrich did not return several requests for comment about the money his campaign still owes.

According to the latest FEC filings, Gingrich’s official campaign committee, still has $4.63 million dollars in unpaid bills. Among all major party presidential candidates from 2012, only Gingrich and Rick Santorum’s campaigns remain in debt, with Santorum owing less than one-eighth of the amount of the debt Gingrich racked up.

The Gingrich campaign’s IOU’s are spread across the county and owed to organizations large and small. The biggest chunk of the debt, nearly $1 million, is owed for Gingrich’s use of private jets to fly from event to event through charter travel company Moby Dick Airways. The campaign also owes more than $400,000 for Gingrich’s personal security to the Patriot Group, and $128,000 to the Winston Group, a top Republican polling company based in Washington.

Several other well-known names are also among Gingrich’s creditors, including former Rep. J.C. Watts and Herman Cain for “strategic consulting” and travel, as well as Kellyanne Conway’s The Polling Company, which conducted polls for the Gingrich campaign and is owed more than $20,000.

The campaign’s former manager is still out $27,000 in salary, while the landlord for an office space in Columbia, South Carolinea, is looking for $1,136 in outstanding rent. The last Comcast bill in New Hampshire never got paid, nor did a $718 tab for catering in Sarasota, Florida. Fed-Ex is looking for $33,732 from the campaign, while Twitter was never paid for a $9,000 media buy.

Former Rep. John Sweeney, who is owed more than $24,000 for paying ballot access fees for the campaign, said he still hasn’t been paid and hasn’t heard from the campaign for about six months.

But the Gingrich campaign isn’t the first Gingrich organization to run into serious money problems.

In 2011, Gingrich’s political non-profit organization, American Solutions for Winning the Future, dissolved in debt and was sued for unpaid rent after Gingrich stepped away to focus full time on his presidential run. It cratered despite the fact that it had raised more than $50 million in the previous four years.

In 2012, Gingrich’s for-profit health care think tank, the Center for Health Transformation, declared bankruptcy. Once a health-industry darling focused on “patient-centered” health reform, the group went from riches to rags after Gingrich launched his presidential campaign. The Washington Post reported the think tank raised $59 million between 2003 and 2011, but declared liabilities between $1 million and $10 million when it filed for Chapter 7 protection.

Later that year, WellStar Health System bought the center’s name and website for $20,000.

Bankruptcy isn’t an option for Newt 2012, though. According to Larry Noble, general counsel for the Campaign Legal Center, candidates like Gingrich must either raise additional campaign funds to retire what their campaign owes or work with debtors on an agreement to partially pay or forgive the debt, which must be approved by the FEC. There’s no deadline for paying it off, Noble said, but eventually both the campaign and the people owed the money are in danger of breaking campaign finance laws.

“Eventually, if a company leaves debts outstanding it becomes an illegal contribution,” Noble said. “So the companies have to show they are making normal and usual efforts to collect the debt.”

So far, Gingrich isn’t making much progress on his end. Although he launched a joint fundraising committee in 2013 to retire the debt called the Committee for America, there hasn’t exactly been a stampede of donors. The Committee for America raised $95 in 2015 and $57 so far in 2016.

Gingrich isn’t personally liable for the debts, but he could always pay some or all of it off himself, as Carly Fiorina did to pay off her 2012 Senate run. The last time Gingrich filed a personal financial disclosure in 2011, he was worth at least $6.7 million through his network of books, speeches, and TV contracts.

The good news for the people still looking to get paid is that Gingrich joining a presidential ticket would make it much easier for him to raise campaign cash. The bad news is that there’s no law that says Gingrich has to pay off his old campaign debts before he launches an entirely new campaign. Gingrich can pay who he wants when he wants.

“Nobody said it was fair,” Noble said.