Apple has received at least $6 per American taxpayer over the last five years in the form of interest payments on billions' worth of United States Treasury bonds, according to a Wednesday report by Bloomberg

Citing Apple’s regulatory filings and unnamed sources, the business publication found “the Treasury Department paid Apple at least $600 million and possibly much more over the past five years in the form of interest.” By taking advantage of a provision in the American tax code, Bloomberg says that Apple has “stashed much of its foreign earnings—tax-free—right here in the US, in part by purchasing government bonds.”

As The Wall Street Journal reported in September, American companies are believed to be holding approximately $2 trillion in cash overseas that is shielded from US taxes. Under American law, companies must pay a 35-percent corporate tax rate on global profits when that money is brought home—so there is an incentive to keep as much of that money overseas as possible.

Ars reported previously that Apple pays an effective 2.3 percent tax rate on overseas profits by using various legal tax shenanigans across several countries as a way to minimize its tax burden. Google, Microsoft, and many other large multinational corporations engage in similar behavior. (Ars has also detailed how such arrangements typically work.)

Earlier this year, the Department of Treasury announced that the White House would like to "impose a one-time transition toll charge of 14 percent on untaxed foreign earnings that US companies have accumulated overseas. The earnings subject to the one-time tax could then be repatriated without any further US tax." (During the presidential campaign, Donald Trump said he would like to see a tax holiday of 10 percent.)

Omri Marian, a tax law professor at the University of California, Irvine told Ars that this strange bond arrangement had been around for decades.

“Basically the US government is borrowing the offshore money, on which no tax was paid to the US (theoretically at 35 percent),” he e-mailed. “So the US government is ending up paying interest on borrowing money in which it theoretically has a 35 percent ownership interest. On the other hand, you could argue that if not for the exception [multinational corporations] would be discouraged from purchasing US debt, or at least disadvantaged in purchasing the debt compared to foreign MNCs who do not necessarily have to pay tax on foreign profits.”

Another tax law professor, Samuel Brunson, of Loyola University-Chicago, largely concurred, noting that the US government seems to be making the best of a questionable, albeit legal, situation.

“What to think of this probably depends on how much you think Apple is cheating by keeping money offshore,” he e-mailed. “If they're cheating—if their actions are unfair—it stands to reason that getting an investment return from the government is also unfair. If it's not cheating, though, that it can effectively repatriate some of its money without paying taxes (through carefully-defined investments that the government has approved) isn't necessarily a bad thing.”