Tax for the CFO: Should Pfizer Acquire Allergan?

On November 20, 2015, the chief financial officer of Pfizer Inc. (Pfizer) was preparing to make a recommendation about whether to proceed with or stop merger talks between Pfizer and Allergan plc (Allergan), a pharmaceutical company with headquarters in New Jersey but tax residence in Ireland. Informal talks had been going on for almost a month, but both sides were rapidly approaching the pre-arranged deadline. The two teams had less than a week to either formally agree to proceed with a merger or walk away. Formalizing the agreement meant activating a US$400 million breakup clause that would make it costlier to call the deal off at a later date. Allergan’s Irish tax residency made this merger both attractive and concerning. While it provided the opportunity to lower Pfizer’s worldwide tax rate, the U.S. Treasury Department had recently announced regulatory changes targeting mergers that relocated a company’s tax residence to a low-tax country (called “tax inversions”). Pfizer’s legal team members were confident that the announced changes would not affect the proposed merger with Allergan. However, they were less certain about if—and when—the U.S. Treasury Department might make changes again.