Pfizer Inc. And Allergan Plc Offices As They Combine In $160 Billion Deal [Getty Images]

Signage is displayed at an Allergan Plc office in Medford, Massachusetts, U.S., on Monday, Nov. 23, 2015. Pfizer Inc. and Allergan Plc agreed to combine in a record $160 billion deal, creating a drugmaking behemoth called Pfizer Plc with products from Viagra to Botox and a low-cost tax base. Photographer: Scott Eisen/Bloomberg via Getty Images

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