Just as lawyers with Chicago pharmaceutical company AbbVie prep the company for its tax-saving flight overseas to the newly-acquired Irish headquarters of Shire, whose U.S. presence is based in Exton and Wayne, Air Force One has shown up in the rear view mirror.

A sudden nervous streak hit Shire shareholders this week when “the Obama administration and Treasury Department said it was exploring ways to deter the growing numbers of tax inversion deals being used by corporations seeking to lower their tax bills,” the Philadelphia Business Journal reported.

Last month’s deal not only drew widespread attention from its status as one of the largest tax inversion moves ever made but also from the aggressive public volley of five escalating takeover offers that peaked at $54.8 billion.

Read more about the latest development and Shire’s stock slump in the Philadelphia Business Journal here, read up on Chesco Business Today’s coverage of last month’s deal here, then check out The Daily Show host Jon Stewart’s amusing take on the trend he calls the “Inversion of the Money Snatchers” in a video clip here.