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Hydrazine Capital
Hydrazine Capital was formed by Sam Altman, the former president of Y Combinator and current CEO of OpenAI.
Hydrazine Capital
Hydrazine Capital was formed by Sam Altman, the former president of Y Combinator and current CEO of OpenAI. The firm invests capital generated from Altman's career as a technology founder and executive, beginning with the sale of his location-based social networking company Loopt in 2012. Hydrazine represents the direct-investment engine for one of the most connected figures in artificial intelligence, functioning not as a structured venture fund but as a discretionary portfolio. The firm concentrates on early to growth-stage companies where Altman's own technical fluency and network provide an edge. Confirmed portfolio companies span nuclear fusion (Helion Energy), collaborative work platforms (Asana), and social media (Reddit), where Altman served as interim CEO in 2014. The strategy also extends to longevity biotechnology with Retro Biosciences, a company Altman personally seeded with a reported $180 million (per MIT Technology Review, 2023). Geography centers on the US West Coast, with positions in California-based hard-tech and software startups, reflecting a Silicon Valley-native deal-sourcing model. Hydrazine operates without the disclosure requirements of a registered investment adviser, and headcount remains undisclosed. Altman co-invests alongside leading venture firms, having participated in rounds for companies like Worldcoin, a cryptocurrency and digital identity project he co-founded. Philanthropic activity channels through Altman's personal giving rather than a named foundation, though commitments have included large pledges to universal basic income research. In April 2024, Altman joined the Giving Pledge, though the document outlines a structure involving a donor-advised fund rather than integrating with Hydrazine (per the Giving Pledge, April 2024). The structural differentiator is the operator-identity of the capital source. Unlike a family office managing inherited wealth, Hydrazine's investment thesis is inseparable from Altman's own active career; his board seats, advisory roles, and reputation for backing ambitious, unscalable science projects shape the portfolio access. The firm is a bet-on-the-jockey vehicle where the jockey is also the asset allocator — a concentrated exposure to one individual's judgment and network rather than a diversified institutional platform.
General information
Firm type
Single Family Office
Year founded
—
AUM
Undisclosed
Location
Region
North America
Country
United States
City
Mountain View
Corporate office
Mountain View, CA, United States
Principals
Sam Altman
Founder
Sector focus
Frequently asked questions
Who runs investment decisions at Hydrazine Capital?
Sam Altman is the controlling principal and sole publicly known investment decision-maker. The firm has not disclosed a professionalized investment committee or external advisors. Altman's personal network and technical judgment drive allocation choices, consistent with a founder-operated single-family office model.
Does Hydrazine Capital invest in venture funds or only directly into companies?
The firm primarily makes direct investments in private companies. Public portfolio disclosures do not show a pattern of fund-of-funds commitments common at institutional family offices. The few known positions are all direct equity stakes in startups where Altman has personal or professional proximity to the founders.
What is the relationship between Hydrazine Capital and OpenAI?
Hydrazine Capital is Sam Altman's personal investment firm and is operationally distinct from OpenAI, where he serves as CEO. Altman has publicly stated he holds no direct equity in OpenAI. The portfolio companies are independent entities, though some, like Worldcoin, share a founder in Altman.
Which sectors does Hydrazine Capital avoid?
There is no public investment policy identifying excluded sectors. However, based on the observable portfolio concentration in deep tech, enterprise software, and AI-adjacent businesses, the firm does not appear active in consumer packaged goods, traditional retail, or hydrocarbon-based energy. No positions in tobacco, defense contracting, or extractive industries have been identified.
How large is Hydrazine Capital?
Hydrazine Capital does not publicly disclose assets under management. Given the known sizes of individual bets — including a reported $180 million commitment to Retro Biosciences — the implied capitalization is substantial for a single-principal vehicle. Any precise figure remains an external estimate.
Does Sam Altman run any other investment vehicles alongside Hydrazine Capital?
Yes. In addition to Hydrazine, Altman has been associated with Apollo Projects, a vehicle for backing high-conviction science and energy companies. The boundaries between these entities are not publicly defined with precision. Hydrazine appears to be the older and more generalist vehicle, while Apollo consolidated later-stage, capital-intensive energy and biotech bets.
How does Hydrazine Capital source its deals?
Sourcing is predominantly network-driven through Altman's roles at Y Combinator and OpenAI. As a former Y Combinator president and a central node in the San Francisco AI ecosystem, Altman sees deal flow that is unavailable to most institutional investors. The firm does not advertise a formal origination team or open application process for founders.
Profile maintained by Altss using OSINT (open-source intelligence), regulatory filings, licensed data partners, and verified direct submissions. Read the methodology. Last updated: . Continuous refresh with full update cycles at least every 30 days.
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