Shifting IP, rather than headquarters, is also a strategic political move, said Robert Willens, an independent tax consultant. A true inversion entails merging with a foreign firm and generally requires disclosures -- but shifting IP doesn’t involve the same scrutiny, and can happen quietly, shielded from finger-wagging by U.S. lawmakers or the president.

Both parties have railed against inversions, and ending the practice is probably one of the few things former President Barack Obama and Trump agree on. Obama called the moves “unpatriotic,” and Trump has said he’s “disgusted” with them.

Many other countries with lower corporate rates have an additional source of tax revenue, such as a value added tax, so they can afford to keep rates low. The U.S. doesn’t have a VAT, and likely won’t as long as Republicans control Congress because it’s viewed as a tax increase.

Unless tax writers can get the corporate rate into the mid-to-low teens (which would require finding additional revenue or adding trillions more dollars to the budget deficit), companies will continue to shift their easiest-to-move assets like IP to countries where it’s the least expensive to keep them, tax experts said.

Unknown IP Locations
Researchers at the U.S. Commerce Department’s Bureau of Economic Analysis seem to agree. “Although the ultimate effects of the 2017 changes to U.S. tax law remain to be seen, there is reason to believe that the incentives for this behavior have not disappeared,” they said in an August report, referring to putting IP overseas.

It’s hard to know just how much intellectual property U.S.-based companies hold overseas. Corporate filings show few details about where such property is located, and companies are hesitant to disclose the information for public relations reasons.

For example, Apple Inc.’s filings show where about 3.6 percent of its profits are earned, according to analysis from researchers at the University of Copenhagen and University of California Berkeley. For Alphabet Inc.’s Google, the location of about 1.4 percent of profits is visible, the data shows. And less than 1 percent of Facebook Inc. and Nike Inc.’s profits were tied to a specific jurisdiction in their public disclosures.

Lure of Ireland
Apple and Google have said in recent filings that any change in Ireland’s tax rates could be material to their financial statements, a sign that they intend to maintain their employee presence and assets there. Apple, Alphabet, Facebook and Nike declined to comment.

Ireland’s National Treasury Management Agency said its own IP numbers have been distorted in recent years because of “onshoring” by U.S. companies. About 65 percent of the value of the technology produced in Ireland in 2015 was from U.S. owned-companies, a figure that the country said it expects to continue to expand even in the wake of the tax law.

Corporate inversions, like those conducted by Burger King Worldwide Inc., Johnson Controls International Plc and Medtronic Plc, were a driving force behind the tax overhaul. Under Obama, the Treasury Department issued rules to deter inversions, but the tax law was intended to be the final blow for switching headquarters and IP shifting.