AI infrastructure and autonomous defense dominate March 2026’s biggest startup rounds
Investors poured money into the plumbing of artificial intelligence and autonomous defense in March 2026, with the two largest startup rounds topping a combined $3.8 billion. The month’s biggest checks included a $2 billion raise for battlefield AI and a $1.8 billion financing for autonomous warships, underscoring where late-stage capital is concentrating.
Data compiled for March shows a cohort led by AI infrastructure, defense autonomy and robotics, alongside sizable financings in mobility, enterprise software and health tech. Several notable rounds illustrate the spread. Palo Alto–based Also, which builds small electric vehicles for micromobility, including modular e-bikes, advanced with a Series C.
Founded by Chris Yu in 2025, the company has now raised $505 million in total equity funding. The latest round drew DoorDash, Greenoaks and Prysm Capital among its investors; the company also counts Eclipse as a backer. Another Bay Area entrant, Axiom, closed a Series A to develop AI tools for verifying proofs and supporting mathematical reasoning.
Founded by Carina Hong in 2025 and based in Palo Alto, Axiom has now raised $264 million in total equity funding. Investors in the round included B Capital, Greycroft, Madrona, Menlo Ventures, Toyota Ventures and Triatomic Capital. In health care, Miami-based eMed secured a Series A as it expands employer-sponsored population health programs that pair GLP-1 treatment with clinical support.
Founded in 2020 by Dr. Patrice A. Harris, eMed has now raised $200 million in total equity funding, with investors including Aon, Joe Lonsdale, Antonio Gracias, Tom Brady and Jeff Aronin, among others. On the infrastructure side of AI, Saratoga, California–based Eridu raised a Series A to build networking technology designed to improve performance and efficiency for large-scale AI systems.
Founded in 2024 by Drew Perkins, Mike Capuano and Omar Hassen, the company has now raised $200 million in total equity funding. Investors in the round included Bosch Ventures, Capricorn Investment Group, Eclipse, Fusion Fund, Hudson River Trading, Matter Venture Partners, MediaTek, Osage University Partners, SBVA, Socratic Partners, TDK Ventures, VentureTech Alliance and Zelda Ventures.
The concentration of capital in AI infrastructure and autonomous defense signals where investors see near-term demand and defensible moats, while the appearance of mobility and health tech among the month’s larger financings shows breadth beyond core AI.
With multi-billion-dollar checks already flowing into defense autonomy and compute, the next quarters will test how quickly these capital-intensive bets translate into scaled deployments.