# Ah Bio
Ah Bio is the family of dedicated bio and healthcare venture funds raised and managed by AH Capital Management, L.L.C., the Delaware-registered investment adviser known publicly as [Andreessen Horowitz](https://www.edgepedia.org/andreessen-horowitz) (a16z). It is a fund series within a multi-stage venture firm rather than a standalone firm: the AH Bio funds are Delaware pooled venture capital vehicles whose general partners are managed by AH Capital Management, whose principal owners are [Marc Andreessen](https://www.edgepedia.org/marc-andreessen) and [Ben Horowitz](https://www.edgepedia.org/ben-horowitz) and which has been in business since 2009.[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt) • [2](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing) Across funds filed between 2015 and 2022, verified Form D filings for Funds III and IV disclose USD 2.25 billion sold, with an additional unverified USD 200 million attributed to Fund I by an aggregator profile; a new vehicle, the AH Bio Ecosystem Fund, L.P., was filed in December 2024.[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt) • [3](https://www.sec.gov/Archives/edgar/data/2048225/000110465924128017/0001104659-24-128017-index.html)
| Fact | Detail |
|---|---|
| Manager | AH Capital Management, L.L.C. (Andreessen Horowitz), in business since 2009[2](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing) |
| Headquarters | 2865 Sand Hill Road, Suite 101, Menlo Park, California[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt) |
| Principals | Marc Andreessen and Ben Horowitz, principal owners of the adviser and managing members of the general partner of Fund III and of the Ecosystem Fund[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt) • [3](https://www.sec.gov/Archives/edgar/data/2048225/000110465924128017/0001104659-24-128017-index.html) • [2](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing) |
| Sector | Bio and healthcare venture capital |
| Disclosed fund capital | USD 2.25 billion verified on Form D (Funds III–IV, 2020 and 2022 vintages); an unverified USD 200 million is attributed to Fund I (2015 vintage)[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt) • [4](https://capedge.com/company/1889476/filings) • [5](https://data.kando.tech/company/ah-bio-fund-i-lp) |
| Adviser's total AUM | USD 74,739,846,609.77 discretionary regulatory AUM as of December 31, 2024[2](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing) |
| Status (September 2026) | Active; Fund IV still filing into August 2026; new Ecosystem Fund vehicle filed December 2024[3](https://www.sec.gov/Archives/edgar/data/2048225/000110465924128017/0001104659-24-128017-index.html) • [4](https://capedge.com/company/1889476/filings) |
## History and people
The series began with AH Bio Fund I, L.P., a 2015-vintage fund that an unverified aggregator profile reports as closing USD 200,000,000 from 67 investors on 12 November 2015.[5](https://data.kando.tech/company/ah-bio-fund-i-lp)
Each fund's Form D names the same leadership. The Fund III filing, signed on 4 February 2020 by [Scott Kupor](https://www.edgepedia.org/scott-kupor) as Chief Operating Officer of AH Bio Fund III, L.P., lists Marc Andreessen and Ben Horowitz as executive officers and managing members of the general partner.[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt) Day-to-day investing is run by the firm's Bio + Health partners: in the February 2020 announcement of Bio Fund III, the firm named [Vineeta Agarwala](https://www.edgepedia.org/vineeta-agarwala), Jorge Conde, Vijay Pande, and [Julie Yoo](https://www.edgepedia.org/julie-yoo) as the fund's general partners, with Pande described as the founder of the Bio + Health team.[6](https://a16z.com/bio-fund-iii/) The composition of the team after 2020 is not established by the sources kept for this article.
## Strategy
The firm's stated bio thesis is biology as engineering: backing founders using AI to discover new drugs, using data to give a real-world view of how patients move through healthcare, and programming cells to fight disease.[6](https://a16z.com/bio-fund-iii/) This framing differs from traditional life-science VC in that it treats biology as a computational and engineering discipline, though the firm's own marketing is the source of this characterization.
The adviser's Form ADV describes its funds independently as investing in early- and later-stage private companies at the intersection of biology, computer science engineering, AI, games, and healthcare, and also in cryptocurrencies, application tokens, protocol tokens, blockchain-based assets, and other digital assets.[2](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing) The bio funds therefore sit inside a multi-strategy adviser whose mandates extend well beyond healthcare.
## Funds, by the numbers
The fund-by-fund record from Form D filings:
- **AH Bio Fund I, L.P.** (2015 vintage): USD 200,000,000 from 67 investors, per an unverified aggregator profile only.[5](https://data.kando.tech/company/ah-bio-fund-i-lp)
- **AH Bio Fund III, L.P.** (2020 vintage): USD 750,000,000 sold, equal to its total offering, with first sale 31 January 2020 and 94 investors; the filing was made 4 February 2020.[1](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt)
- **AH Bio Fund IV, L.P.** (2022 vintage): a Form D filed 21 January 2022 reported a USD 1.5 billion offering with USD 1.5 billion sold to 149 investors.[4](https://capedge.com/company/1889476/filings)
The firm announced Bio Fund III as a new $750M bio fund, its third dedicated bio vehicle, on 4 February 2020, matching the Form D amount.[6](https://a16z.com/bio-fund-iii/) Summed across the verified filings, the disclosed Form D capital for Funds III and IV is about USD 2.25 billion; adding the unverified Fund I figure brings the series to about USD 2.45 billion. For scale, the bio series is a minority of the adviser's book: AH Capital Management reported USD 74.7 billion in discretionary regulatory assets under management as of 31 December 2024.[2](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing) How this total compares with other dedicated bio venture firms such as [Flagship Pioneering](https://www.edgepedia.org/flagship-pioneering), Third Rock Ventures, or [ARCH Venture Partners](https://www.edgepedia.org/arch-venture-partners) cannot be established from the sources kept here.
## Recent developments
Two post-2023 developments are on the record. First, a new vehicle, the AH Bio Ecosystem Fund, L.P. (CIK 0002048225), a Delaware entity at the same 2865 Sand Hill Road address, filed a Form D notice of exempt offering on 12 December 2024; its final size is not disclosed in the kept sources.[3](https://www.sec.gov/Archives/edgar/data/2048225/000110465924128017/0001104659-24-128017-index.html) Second, AH Bio Fund IV remained active into 2026, with Forms 3, and 4 and a Schedule 13D filed in August 2026, and Marc Andreessen filed a Form 4 dated 17 October 2024 relating to the fund.[4](https://capedge.com/company/1889476/filings) The firm's Bio + Health page, retrieved in 2026, markets an ongoing franchise with "five full operating teams" of MDs, PhDs, scientists, and technologists, indicating the bio and healthcare practice continued after Fund IV.[7](https://a16z.com/bio-health/) No Fund V vehicle is confirmed in the sources kept here.
## References
1. [AH Bio Fund III, L.P. — Form D (full text), SEC EDGAR](https://www.sec.gov/Archives/edgar/data/1799477/0001799477-20-000001.txt)
2. [AH Capital Management, L.L.C. — 2025 Form ADV Brochure, SEC Investment Adviser Public Disclosure](https://files.adviserinfo.sec.gov/IAPD/Content/Common/crd_iapd_Brochure.aspx?BRCHR_VRSN_ID=968053&tpcc=NL_Marketing)
3. [SEC EDGAR Form D filing index — AH Bio Ecosystem Fund, L.P. (Accession 0001104659-24-128017)](https://www.sec.gov/Archives/edgar/data/2048225/000110465924128017/0001104659-24-128017-index.html)
4. [AH Bio Fund IV, L.P. SEC Filings — CapEdge](https://capedge.com/company/1889476/filings)
5. [AH Bio Fund I LP — VC DATALAB profile (unverified directory)](https://data.kando.tech/company/ah-bio-fund-i-lp)
6. [Bio Fund III | Andreessen Horowitz](https://a16z.com/bio-fund-iii/)
7. [a16z Bio + Health (firm's own team page)](https://a16z.com/bio-health/)
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*Topic: Encyclopedia › Society and history › Economics and business › Finance › Venture capital and private equity › Venture capital firms of the Americas › Healthcare and life sciences investors › Biopharma and biotech investors*
*Initially written Sep 17, 2026 · Edited: Oct 11, 2026; Oct 15, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license