There is no love lost between the U.S. Treasury and U.S. companies seeking offshore tax homes. Absent congressional action to stem the inversion tide, the Treasury and IRS are left to flex their regulatory and administrative authority. In November, the Treasury and IRS issued Notice 2015-79, the second notice in as many years pronouncing new antiinversion measures. The recent notice describes guidance alluded to in last year’s Notice 2014-52—namely, rules that further attack Section 7874 avoidance transactions and reduce the benefits of certain post-inversion transactions.