8. Gilead Sciences
This is also a research-based company in California. It has a great past portfolio and has found a great breakthrough in HIV/AIDS research and also the treatment of Hepatitis infections. They are known for developing innovative drugs and therapies such as; virology, oncology, inflammation, respiratory among others. Their best-selling drug was Harvoni which is a Hepatitis C treatment drug. Others include Truvada and Epclusa; all these have boosted their revenue to about $25.65 Billion dollars.