Robert Nelsen is a cofounder and managing director of ARCH Venture Partners. He joined ARCH at its founding and played a significant role in the early sourcing, financing, and development of more than 100 companies, including 27 that have reached valuations exceeding $1 billion. His seed and early-stage investments include Illumina (ILMN); Alnylam Pharmaceuticals (ALNY); Juno Therapeutics (JUNO); Beam Therapeutics (BEAM); Karuna Therapeutics (KRTX); Lyell Immunopharma; Array BioPharma (ARRY); Unity Biotechnology (UBX); Hua Medicine (2552:HK); Vir Biotechnology (VIR); Agios Pharmaceuticals (AGIO); Sage Therapeutics (SAGE); GRAIL; Gossamer Bio (GOSS); Ikaria; Kythera Biopharmaceuticals (KYTH); Receptos (RCPT); Aviron (AVIR); Denali Therapeutics (DNLI); Rubius Therapeutics (RUBY); Syros Pharmaceuticals (SYRS); Sana Biotechnology; KSQ Therapeutics; NetBot; Bluebird Bio (BLUE); R2 Technology; XenoPort (XNPT); Fate Therapeutics (FATE); Caliper Life Sciences (CALP); Trubion Pharmaceuticals (TRBN); Adolor (ADLR); deCODE Genetics; Editas (EDIT); 10x Genomics; Semma Therapeutics; IDUN Pharmaceuticals; Classmates.com; Sienna Biopharmaceuticals (SNNA); and Everyday Learning Corporation.

Nelsen is a director of Vir Bio, GRAIL, Sana Biotechnology, Beam Therapeutics, Unity Biotechnology, and Denali Therapeutics, and serves as chairman of Hua Medicine, among others. He previously served as a trustee of the Fred Hutchinson Cancer Research Institute and the Institute for Systems Biology, and was a director of the National Venture Capital Association. Nelsen holds a BS from the University of Puget Sound with majors in economics and biology and an MBA from Chicago Booth.