From aerospace to biotech
Castle Fund is dedicated to advancing groundbreaking solutions in biotech, energy, aerospace, robotics, and chips. We seek founders securing patents, trade secrets and partnerships that create lasting impact.
The team has worked together before.
Ex-founder, prior Venture Partner at Asymmetry Ventures (deep tech fund), manages 5k LP AngelList syndicate (100+ deals, $20M+ AUM), and has two decades of legal and BD experience in IP licensing and distribution.
Ex-Blackstone, fractional CFO for biotech startups, and venture partner for multiple deep tech funds; raised $10M for 20+ AngelList deals at Jolt VC.
15+ years in private practice in Los Angeles, representing emerging fund managers exclusively. Author of the Law of VC Substack.
Two decades in software engineering, venture innovation, and patent portfolio development, including at Intellectual Ventures and Xinova. Technical advisor to Perkins Coie.
Patent prosecutor and litigator running his own IP consultancy. Ran IP departments at Fortune 500 companies and licensed billions of dollars in IP. Previously ExxonMobil, Cabot, Chemtura, Celanese, and Ulterra.
Biophysicist who worked on CRISPR and cellular engineering at Caltech and Imperial College. Asimov Press reaches 500k monthly readers. Fellow at Arc Institute and former fellow at Astera Institute.
Band of Angels is the oldest angel group in California, with 400+ investments and a 28% exit rate since 1994, including 17 IPOs. Ph.D. in Aerospace Engineering from Stanford.
Fund I, first closings.
Picks and shovels for orbital data centers. Strong IP around thermal management and distributed compute. Founded by JPL veteran and GP of Mandala Space Ventures.
Aerospace ↗
A novel material with 10X the power density of silicon photovoltaics. Valuable when weight matters (e.g. space, defense).
Energy
Gene therapy for dry AMD blindness, targeting a blockbuster market with no approved full cures.
BiotechWarehoused investments
Two mature verticals with active M&A, plus the enabling tech that serves them.
The bridge between invention and monetization
At seed, revenue is volatile or absent. IP is one of the few things you can actually underwrite: it signals focus, sets margin potential, and tells you whether a company can hold a position once incumbents notice.
Patent strategy exposes what a team believes is defensible. It shows focus and margin potential at a stage when the financials cannot.
IP drives enterprise partnerships and changes the shape of negotiations. It is a commercial instrument well before it is a legal shield.
IP is a key factor in deep tech M&A. The focus can capture the decacorn outliers that drive fund returns and shorten time to exit.
Recent IP-driven exits
Three careers most investors have only one of. The overlap is where the pattern recognition lives.
Three exits as founder and early operator. 100+ personal investments across deep tech.
IP attorney at Greenberg Traurig, then nine-figure licensing at Intel, Sony, and Amazon.
Venture Partner at Asymmetry Ventures and manager of a 5,000-LP AngelList syndicate.
Figures reflect Daniel Gould's personal angel portfolio (2006–2020) and the Asymmetry Ventures AngelList syndicate (2021–2023), not Castle Fund I. Past performance is not indicative of future results. Full portfolio filterable by sector available here.
