Annexon, Inc.
formerly Annexon BiosciencesIPOUnlocking the next generation of complement therapies
Public · South San Francisco, United States · Founded 2016 · $278.0M raised
- Headquarters
- South San Francisco, California
- Employees
- 1–10
- Founded
- 2016
- Business Model
- B2B
- Website
- annexonbio.com
- Total Funding
- $278.0M
- Last Round
- Series ENov 2025
- Rounds
- 9
- Type
- Public
Totals include recorded grants and other qualifying funding, not just equity. What counts toward funding.
Indexed holds 11 funding rounds and 16 investors for this company. The full record is or through the API.
About
Annexon Biosciences (Nasdaq: ANNX) is a clinical-stage biopharmaceutical company developing a new class of complement medicines targeting the classical complement pathway via C1q inhibition. Its pipeline addresses autoimmune, neurodegenerative, and ophthalmic disorders, with candidates including ANX005, ANX007, and ANX009 in clinical development. The company was founded in 2011 by Arnon Rosenthal and Ben Barres.
Summary
Annexon, Inc. is a Biotech company based in South San Francisco, United States, founded in 2016. It has raised $278.0M in total across 9 rounds, most recently a Series E round in Nov 2025. Investors include GV, Alta Partners and Satter Investment.
Tech & App Stack
6 technologies & apps tracked
Every product and vendor across these categories, with where each signal came from.
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Funding & Exit History
Nov 2025
Sign up to see all 11 events
Funding: Series A through Series E. Amounts, valuations, and investors where available.
Investors
GV
1 round
Alta Partners
1 round
Satter Investment
1 round
Bain Capital Life Sciences
1 round
Correlation Ventures
1 round
Goldman Sachs
1 round
Wells Fargo
1 round
Omega Funds
1 round
Cowen Healthcare Investments
1 round
BlackRock
1 round
Deerfield Management
1 round
Eventide Asset Management
1 round
Farallon Capital
1 round
Janus Fund
1 round
Surveyor Capital
1 round
Adage Capital
1 round
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