In December 2018, GlaxoSmithKline plc (GSK) and Pfizer Inc. agreed to combine their consumer healthcare businesses through a multi-billion dollar transaction. GSK markets common over the counter health care products such as Excedrin, TUMs, Prevacid, and Triaminic, while Pfizer markets Nexium, Advil, Robitussin, and Dimetapp. Compass Lexecon teams in the US and UK provided economic and econometric analyses in support of the transaction. In the US, the Compass Lexecon team presented detailed econometric results to the FTC showing little competition between the parties’ brands, and strong pricing constraints from generic medications. In the UK, the Compass Lexecon team supported the European Commission’s review along with other international filings. The deal received clearance without a second request in the US in March, 2019, and received approval in the EU in July 2019. The Washington, DC-based Compass Lexecon team was led by Loren Smith and included Chris Rybak, Ben Wagner, John Campbell, Rob Oandasan, Eric Yde, John Hassett, Carlos Paez, and Natalie Kronebusch. The non-US-based Compass Lexecon team included Kirsten Edwards-Warren, John Davies and Marion Chabrost. Compass Lexecon worked closely with a legal team from Kirkland and Ellis LLP that was led by Matthew J. Reilly, Paula Riedel, Marin Boney, Jeffrey Ayer, Stephanie Greco, Joel Gory, Lauren Taylor, Jordan Goater and Arjun Chandran, and with a team from Ropes & Gray LLP that was led by Michael S. McFalls and Jonathan S. Klarfeld.