Investor appetite for large, late-stage bets remained strong this week, with security, energy and deep-tech companies drawing some of the biggest venture checks of the year. Leading the funding charts was identity security firm Saviynt, followed closely by a cluster of capital-intensive startups operating at the intersection of AI and energy infrastructure.
From geothermal power to supersonic aviation and space systems, this week’s top funding rounds highlight where investors see long-term, defensible growth opportunities.
Here are the 10 largest U.S. funding rounds announced this week:
1. Saviynt — $700 million (AI Identity Security)
El Segundo–based Saviynt raised $700 million in a Series B round led by KKR, valuing the 15-year-old company at approximately $3 billion. The company provides AI-driven identity governance and security solutions for enterprises.
2. Unconventional AI — $475 million (AI Energy Efficiency)
Unconventional AI secured $475 million in seed funding to develop computing systems designed to improve energy efficiency for AI workloads. Andreessen Horowitz and Lightspeed Venture Partners led the round for the Bay Area startup.
3. Fervo Energy — $462 million (Geothermal Energy)
Houston-based Fervo Energy closed a $462 million Series E led by B Capital. The funding will support the development of large-scale geothermal projects, including a major initiative in western Utah.
4. Boom Supersonic — $300 million (Aerospace and Energy Systems)
Boom Supersonic raised $300 million in financing led by Darsana Capital Partners. While best known for its work on high-speed commercial aircraft, the company is also gaining attention for its natural gas turbine technology aimed at powering AI data centers.
5. K2 Space — $250 million (Space Technology)
Satellite platform developer K2 Space secured $250 million in Series C funding led by Redpoint. Founded in 2022, the Torrance, California–based company is now valued at $3 billion.
6. Harness — $240 million (Software Development)
Software delivery automation firm Harness raised $200 million in Series E funding, along with an additional $40 million earmarked for employee liquidity. Goldman Sachs led the round, valuing the company at $5.5 billion.
7. Impulse Dynamics — $158 million (Medical Devices)
Impulse Dynamics, which develops heart failure treatment devices, raised over $158 million in a round led by Sands Capital Ventures and Braidwell. The financing follows expanded Medicare coverage for its core product.
8. Fal — $140 million (Generative AI Platforms)
Generative AI startup Fal closed a $140 million Series D led by Sequoia Capital. This marks the company’s third funding round in 2025, reflecting strong investor interest in real-time AI content infrastructure.
9. Sanegene Bio — $110 million (Biotechnology)
RNAi therapeutics company Sanegene Bio raised more than $110 million in Series B funding. Founded in 2021, the Boston-headquartered startup also maintains significant operations in China.
10. BlossomHill Therapeutics — $84 million (Cancer Therapeutics)
BlossomHill Therapeutics secured $84 million in a Series B extension round led by Janus Henderson Investors, Brahma Capital and BioTrack Capital to advance its oncology drug pipeline.
