GSK is a British multinational pharmaceutical company that specializes in researching, developing, and manufacturing a wide range of prescription drugs and vaccines. The company was founded in 2000 through the merger of Glaxo Wellcome and SmithKline Beecham. GSK's products are used to treat a variety of conditions including respiratory diseases, HIV/AIDS, and cancer. The company operates in over 150 countries and has a workforce of over 99,000 employees. GSK is headquartered in Brentford, England and is listed on the London Stock Exchange and the New York Stock Exchange.