Matheson has advised Allergan on a definitive merger agreement under which Actavis will acquire Allergan in a $66 billion cash and stock transaction. The merger will create one of the top 10 global pharmaceutical companies by revenue, with combined annual pro forma revenues of over $23 billion expected in 2015.

The Matheson team advising Allergan included corporate partners Patrick Spicer and George Brady, tax partner Shane Hogan and Head of US Offices, John Ryan. This continues Matheson’s track record of advising on high profile international M&A transactions. Matheson recently advised Auxilium Pharmaceuticals Inc. on its $2.6 billion merger with Endo International plc. Matheson also advised Questcor Pharmaceuticals on its $5.6 billion merger with Mallinckrodt and is advising Perella Weinberg Partners as financial adviser to Medtronic on its $42.9 billion acquisition of Covidien. Matheson advised Actavis on its $8.5 billion acquisition of Dublin-based Warner Chilcott as well as advising Royalty Pharma on its $6.5 billion hostile bid for Elan Corporation, the Irish biotechnology company in 2013.

The transaction has been unanimously approved by the Boards of Directors of both companies. Subject to shareholder and regulatory approval, the transaction is expected to close in the second quarter of 2015.