In July, the American pharmaceutical giant AbbVie, maker of the world’s top-selling drug – the arthritis treatment Humira – reached a blockbuster deal to acquire European rival Shire, best known for the attention-deficit medication Adderall. The merger was cheered by Wall Street, not for what the deal will do to advance pharmaceutical science, but because it will empower the bigger firm, AbbVie, to renounce its U.S. citizenship.
At $55 billion, the AbbVie deal is the largest in a cavalcade of corporate “inversions.” A loophole in American tax law permits companies with just 20 percent foreign ownership to reincorporate abroad, which means that if a big U.S. firm acquires a smaller company located in a tax haven, it can then “invert” – that is, become a subsidiary of its foreign-based affiliate – and kiss a huge share of its IRS obligations goodbye.
