15. GlaxoSmithKline

The year 2015 was one of restructuring for GlaxoSmithKline. First the British drugmaker took over the Novartis consumer brands and vaccines business in a $20 billion deal. Then, in the wake of a full-on business consolidation, GSK cut 350 jobs in its Parsippany, New Jersey, office. On the other hand, the drugmaker's allergy medication Flonase received OTC approval in February and generated almost $100 million in sales during its first 16 weeks on the market, according to marketing firm IRI. That isn't to say that the launch proceeded without incident: Johnson & Johnson sued GSK for making unsupported claims in its Flonase advertising, ones that came at the expense of J&J drugs Benadryl and Zyrtec. The companies settled the dispute in April. Up next? A big change on the personnel front, with CEO Andrew Witty set to retire on March 31, 2017, following nearly a decade with the company. GSK is in the process of identifying a replacement.