Having recently taken on tax-related engagements for Yahoo! Inc. and Darden Restaurants Inc., lawyers from Skadden, Arps, Slate, Meagher & Flom have also scored a role on Pfizer Inc.’s controversial $152 billion pharmaceutical industry union with Allergan Inc.

The Am Law Daily recently reported on the dozen or so firms behind the mega-deal, whose inversion structure could save Pfizer roughly $2.1 billion in taxes. Skadden is serving as corporate and tax counsel to the New York-based acquirer, which would move its headquarters to tax-friendly Ireland if it succeeds in sidestepping regulatory and political scrutiny and absorbs Dublin-based Allergan in early 2016.