Gilead Sciences, Inc. is a US biopharmaceutical company founded on June 22, 1987 by Michael L. Riordan and headquartered in Foster City, California. It trades on Nasdaq under the ticker GILD and is a component of the S&P 500 and Nasdaq-100. The company describes its mission as discovering, developing and delivering innovative therapeutics for people with life threatening diseases.
The business is built around three therapeutic areas: virology, oncology and inflammation. Gilead is best known for its HIV franchise, which includes Biktarvy and Descovy, and it has expanded into cell therapy through Kite and into antibody drug conjugates with Trodelvy. In June 2026 the FDA approved Trodelvy for first line treatment of metastatic triple negative breast cancer, and Gilead and Merck reported positive Phase 3 data in July 2026 for a once weekly oral HIV regimen combining lenacapavir and islatravir.
Gilead employs more than 17,000 people and operates in over 35 countries. Reported revenue was $29.44 billion for fiscal 2025, and market capitalization stood at about $161.8 billion in late July 2026. First quarter 2026 revenue reached $7.0 billion, up 4% year over year, with total HIV sales up 10% to $5.0 billion. The company has been actively acquiring, closing the $7.8 billion Arcellx deal in April 2026 and agreeing to buy German ADC developer Tubulis for $3.15 billion upfront.