Pharmaceutical research and development company AbbVie Inc. (ABBV) acquired Ireland-based Shire Plc. (SHP)—a pharmaceutical company specializing in treatments for rare diseases—to the tune of $53 billion last Friday (July 18, 2014). Shire holders will get cash and stock valued at 52.48 pounds (89.52 dollars) a share.

The acquisition foreshadows the latest trend for companies, particularly in the pharmaceutical industry, to shift their corporate domiciles abroad to enjoy U.S. tax relief. Naturally, this has caused congressional unrest for the hit they will receive, now that their tax revenue from AbbVie has, literally, set sail.

The higher corporate tax rate in the states is pushing companies overseas, as AbbVie’s Chief Executive Officer Richard Gonzalez duly noted, “Today we’re at a disadvantage compared to our foreign competitors, and that’s the debate we should be having around inversions and our tax code.” By 2016, AbbVie’s acquisition deal and change of legal residency will have lowered their tax rate from 22 percent to 13 percent.

The favorable tax climate in Europe has U.S. lawmakers anxious to close the tax break loophole by making inversions difficult, if not impossible, in the future. Until then, U.S. companies will be rushing to set sails and sales offshore.