We know that corporations use offshore tax havens to dodge their fair share of taxes. According to Gabriel Zucman, an economist at UC Berkeley and author of The Hidden Wealth of Nations: The Scourge of Tax Havens, American companies avoid paying $70 billion in taxes every year by parking their profits in low- or no-tax countries.

But the release of the Paradise Papers—thousands of documents leaked from Appleby, an offshore law firm that advises companies and the wealthy on using the tax code to their advantage and is a major player in this market—has shed some new light on the network of financial firms, lawyers, and accountants that make the system work. They’ve also exposed how some of the wealthiest people in the world use various trusts and shell companies to not only make a killing but also to keep their positions from the public’s view.

The most prominent example of this is probably Commerce Secretary Wilbur Ross’s holdings in a shipping company called Navigator, which is closely tied to an energy firm controlled by members of Vladimir Putin’s inner circle, including his son-in-law. Another member of that inner circle controlling the energy firm is Gennady Timchenko, a Russian billionaire on the Treasury Department’s sanctions list. Experts told NBC News that the relationship should have raised red flags, but it wasn’t fully disclosed during Ross’s confirmation process. Senator Richard Blumenthal said members of Congress “were under the impression that Ross had divested all of his interests in Navigator. Furthermore, he said, they were unaware of Navigator’s close ties to Russia.”

But Ross is only one of many within Trump’s circle of advisers and donors whose offshore investments were unveiled in the Paradise Papers. They include Steve Bannon, his erstwhile backer Robert Mercer—who used untaxed money from his offshore holdings to finance Clinton Cash, a book accusing Hillary Clinton of corruption—the Koch brothers, Sheldon Adelson, Secretary of State Rex Tillerson, chief economic adviser Gary Cohn, casino magnate Steve Wynn, and Carl Icahn, among others. Their holdings may not violate any laws—when properly disclosed—but they certainly fly in the face of the “America first” rhetoric their president embraces.

A search of the International Consortium of Investigative Journalists database of the leaks finds two prominent Democrats in the Panama Papers. A holding company tied to former presidential candidate Wes Clark used Appleby to register a new subsidiary on the Isle of Man, where all of its intellectual property now resides. And Penny Pritzker, who served as Commerce Secretary under Barack Obama, appears to have used Appleby to transfer holdings to her children that she claimed on her ethics disclosures to have sold.

Avoiding disclosure—including disclosure of potential conflicts of interest or schemes that might be politically damaging if made public—may be secondary to minimizing those tax bills, but it’s clearly a factor for those whose holdings have been revealed by the Paradise Papers.

The Queen of England’s private estate invested in an offshore trust and, according to the BBC, some of those funds “ended up in the company behind BrightHouse, a chain accused of irresponsible lending, and Threshers, which went bust owing £17.5m in UK tax.” The BBC also reported Prince Charles tripled his money in an offshore investment after he lobbied for changes to international climate agreements that would have benefited the firm. According to The Guardian, Jean-Claude Bastos de Morais, a wealthy businessman who administers Angola’s sovereign-wealth fund, made five investments in his own companies using cash from the struggling country’s “people’s fund.” Stephen Bronfman, an heir to the Seagram family fortune and a key fundraiser for Canadian Prime Minister Justin Trudeau, whose Liberal Party made “a promise to make sure that people were paying their fair share of taxes,” as Trudeau said shortly after being elected, was a key player in “a $60-million US offshore trust in the Cayman Islands that may have cost Canadians millions in unpaid taxes,” according to the Canadian Broadcasting Company. Even U2 frontman Bono, who has long campaigned for debt relief for developing countries, “is under investigation for potential tax avoidance” via a sketchy Lithuanian shopping mall, which was exposed by the Paradise Papers.

Obscuring one’s investments is just one feature of a much larger scam. For corporate America, offshore tax havens aren’t just a means of shifting the tax burden onto the rest of us—they actually serve as profit centers. In 2015, Americans for Tax Fairness estimated that American companies were holding $2.1 trillion in profits in various tax havens around the world, and under current law, they don’t have to pay taxes on them until they “repatriate” those dollars. In theory, that means that all of those profits represent an interest-free, or at least very low-interest, loan from the federal government, which they can then invest as they’d like and pocket the returns. It’s easy to make money with free money from Uncle Sam.

But Gabriel Zucman says “it’s even more than an interest-free loan, because all these profits that are parked offshore are supposed to be taxed upon repatriation in the US at the rate of 35 percent—but they will never be taxed at this rate.” That’s because corporations hold those dollars hostage, demanding occasional “tax holidays” to bring them back to the United States at a fraction of what they owe.

Zucman notes that in 2004 “these behemoth international companies were able to repatriate their offshore earnings at a rate of 5.25 percent. So in practice all these profits that they manage to book in places like Ireland, Jersey, the Cayman Islands, and so on face really tiny tax rates, and that’s the reason why the artificial shifting of profits to low or zero tax places has kept growing over the last years and decades.” Companies promise that they’ll bring those profits back to invest here at home—that’s their leverage for demanding these “holidays”—but, according to William Galston, writing for The Wall Street Journal, “the 15 companies that repatriated the most” profits during the 2004 tax holiday “raised salaries for senior executives, cut more than 20,000 jobs, decreased investment in research, and expanded dividends and stock buybacks. All this happened despite the letter of the law, which specified that the funds be used for investing in research and the workforce and prohibited their use for compensating executives and repurchasing stock.”

Zucman says that according to the latest available data, 63 percent of all the foreign profits made by US firms last year were recorded in just six low- or zero-tax jurisdictions. “Year after year they manage to book a bigger fraction of their global profits in these tiny Caribbean or European islands.”

It’s not like Apple or Microsoft are making a lot of sales in these jurisdictions. There aren’t that many customers in Bermuda or Jersey. The way the scam works, says Zucman, “is that they manipulate the price of their intra-group transactions. So, for example, they might export goods from the US at artificially low prices to Ireland and then import from Ireland at artificially high prices.” The other way they shift their profits overseas is by locating intangible assets, like algorithms or logos or trademarks with their subsidiaries in low tax countries. He offers an example: “Google moved its IT, its intellectual property in 2003 before even being listed as a public company to its Bermuda subsidiary and since then all the profits that are generated by these search technologies accrue to its Bermuda operation. In 2015, Google made $15.5 billion dollars in profits in Bermuda, where the corporate tax rate is 0 percent.” That’s almost three times the island nation’s entire economic output.

Zucman says that it would be exceptionally easy to put an end to this kind of systemic tax evasion. “We could start from the global consolidated profits of firms, and just apportion those profits to each country where sales are made. Think about Apple for instance. If they make 100 billion dollars in profits globally, and 50 percent of their sales in the US, then we could say ‘Okay, 50 percent of their global profits are going to be taxed in the US.’ And you immediately see the beauty of this system. It would put an end to this tax avoidance because right now Apple can move its profits to Jersey but cannot move its customers to Jersey. The customers are in the US, they are in Germany, they are in France. With the system that I describe, we would put an end to corporate tax avoidance.”

Ideally, that would be done on an international basis, but Zucman adds that “any country could adopt it unilaterally. The US could next year say, ‘That’s going to be the way we tax multinational corporations.’ We don’t need international cooperation.”

Instead, Washington lawmakers are going in the opposite direction, pushing for companies and their investors to enjoy yet another “tax holiday” that would allow them to bring their profits back to the US for pennies on the tax dollar that they owe. If history is any guide, they’d pay that cash to their investors through stock buy-backs and dividends, and start the whole process over again next year.