But if it’s a loss for taxpayers, it’s a great deal for Pfizer. As with other companies that have “inverted,” the only thing it has to lose is its tax obligations. Inverted companies almost invariably keep their headquarters and top executives in the United States. They remain listed on United States-based stock exchanges, where they raise capital under the protection of American securities’ laws. The newly combined Pfizer Inc. and Allergan P.L.C., for instance, will be renamed Pfizer P.L.C. and trade under the ticker symbol PFE, Pfizer’s current symbol, on the New York Stock Exchange, according to The Wall Street Journal.

In addition, inverted companies continue to enjoy the protection of patent laws in the United States, as well as their connections, official and unofficial, with federal research agencies — all of which are crucial to drug-company profits. Contrary to popular belief, much high-risk, pathbreaking research and development can be traced not to the big drug companies but to taxpayer-funded research at the National Institutes of Health.

Traditionally, corporate taxation was a way to repay the public for benefits companies received from federal support. But in recent decades, corporate taxes as a share of federal revenue have shriveled. Inversions will only worsen that trend, effectively bolstering corporate profits at the expense of the public.

Pfizer executives, and the executives of inverted companies, don’t put it that way. They say they cannot remain competitive if they have to pay tax on profits at the relatively high United States top rate of 35 percent.

That claim does not stand up. American multinationals routinely take advantage of write-offs that reduce the top rate to a much lower level. Moreover, even an inverted company is supposed to pay tax on earnings generated in the United States at American rates. But by having a foreign parent company in one country — Ireland in this case — while remaining headquartered in the United States, a company can lower its tax bill through an accounting gimmick known as “earnings stripping,” in which profits from the United States are shifted to the foreign parent in the lower-taxed country, thus reducing the American tax bill.