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
• 11.3k employees
• Founded 2015

Maze Therapeutics is a clinical-stage biopharmaceutical company harnessing the power of human genetics to develop novel, small molecule precision medicines for patients living with renal, cardiovascular and related metabolic diseases, including obesity. The company is advancing a pipeline using its Compass platform, which allows it to identify and characterize genetic variants in disease and then link those variants to the biological pathways that drive disease in specific patient groups through a process it refers to as variant functionalization. The company’s pipeline is led by two wholly owned lead programs, MZE829 and MZE782, each of which represents a novel precision medicine-based approach for chronic kidney disease. Maze is based in South San Francisco.

• Post-IPO equity
• 161 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 B
• 102 employees
• Founded 2025

Cartography Biosciences is advancing a differentiated oncology pipeline of antibody-based therapies designed to target tumors with unprecedented precision. The company’s ATLAS and SUMMIT discovery platforms are powered by an industry-leading, fully integrated dataset spanning hundreds of thousands of cell states across healthy tissues alongside large-scale single-cell profiling of patient tumors. By combining petabyte-scale proprietary data, machine learning, and AI-driven biological insights, Cartography is identifying highly specific tumor targets and logic-gated target combinations to generate therapies engineered for maximal tumor selectivity and meaningful patient impact. The company’s lead program, CBI-1214, is a T-cell engager in development for colorectal cancer. CBI-1214 entered the clinic in early 2026 and is currently enrolling and treating patients in a phase 1 trial.

• Series unknown
• 67 employees
• Founded 2020

We are an ingredient innovation company pioneering new forms of purification and biomanufacturing to liberate ingredients from legacy constraints across functionality, flavor, bioactivity, and sustainability.

• non equity assistance
• 53 employees
• Founded 2016