Andreessen Horowitz AI portfolio in San Francisco

OpenAI is an AI research and deployment company dedicated to ensuring that general-purpose artificial intelligence benefits all of humanity. AI is an extremely powerful tool that must be created with safety and human needs at its core. OpenAI is dedicated to putting that alignment of interests first — ahead of profit.To achieve our mission, we must encompass and value the many different perspectives, voices, and experiences that form the full spectrum of humanity. Our investment in diversity, equity, and inclusion is ongoing, executed through a wide range of initiatives, and championed and supported by leadership.At OpenAI, we believe artificial intelligence has the potential to help people solve immense global challenges, and we want the upside of AI to be widely shared. Join us in shaping the future of technology.

• Series unknown
• 10.5k employees
• Founded 2015

insitro is the physical AI company unlocking causal human biology, founded and led by AI pioneer Daphne Koller. By generating the world’s largest integrated multi-modal corpus of human and cellular data, we’ve built the Virtual HumanTM – a genetically anchored causal AI engine that reveals how disease begins, progresses, and can be resolved. Our platform enables us to precisely identify causal genetic drivers and deploy our TherMLTM AI platform to design optimal medicines, advancing a broad pipeline of therapeutics for neuroscience and metabolic diseases. This industrialized architecture creates a self-learning loop: with every biology we onboard, our predictive models grow smarter, accelerating discovery across scales of biology.Join us in transforming the future of medicine!

• Series C
• 256 employees
• Founded 2018

Created by researchers from UC Berkeley, Arena (formerly LMArena) is a community-powered platform to measure and advance the frontier of AI for real-world use. Tens of millions of builders, researchers, and creative professionals come to Arena to use frontier models and give feedback on their responses, shaping a public leaderboard grounded in real-world use.

• Series A
• 70 employees
• Founded 2025

Building a smarter roadmap for precision therapeutics.

• Series unknown
• 66 employees
• Founded 2020

Rezo is a different kind of biopharma company. Our mission is to dramatically increase the success rate of drug development by building a disease-agnostic, fully-integrated, network biology platform that will redefine our understanding of human disease and ability to treat it. Our Founders and members of the Board are a group of esteemed, world-class scientists from the University of California, San Francisco: Nevan Krogan, Kevan Shokat, Sourav Bandyopadhyay, Natalia Jura, as well as renowned biotech executives George Scangos and Norbert Bischofberger. These leaders bring with them a strong track record of amazing discoveries and scientific breakthroughs, leading to very successful companies and many FDA approved drugs.

• Series A
• 45 employees
• Founded 2021