SA国际传媒

Want to keep track of the largest startup funding deals in 2025 with our curated list of $100 million-plus venture deals to U.S.-based companies? Check out The SA国际传媒 Megadeals Board.

This is a weekly feature that runs down the week鈥檚 top 10 announced funding rounds in the U.S. Check out last week鈥檚 biggest funding rounds here.

Hoping to be the first company to commercialize fusion power, led the pack by a long shot for funding this week, pulling in $863 million for its latest round. Beyond that deal, however, it was a rather slow week for large startup funding rounds, although we did see some good-sized financings for the fintech, biotech and vertical AI sectors.

1. , $863M, fusion energy:聽 Devens, Massachusetts-based Commonwealth Fusion Systems, a developer of commercial fusion energy systems, that it raised $863 million in what it described as Series B2 financing from a long list of investors including 鈥檚 . Commonwealth said it is moving closer to being the first in the world to commercialize fusion power.

2. , $115M, oncology: St. Louis-based Wugen, a developer of CAR-T cell therapies to treat T-cell cancers, picked up $115 million in equity financing led by . Seven-year-old Wugen plans to use the financing in part to fund clinical trials.

3. , $58M, fintech: Rain, a developer of infrastructure for stablecoin payments, announced that it secured $58 million in a Series B funding round led by . The raise comes five months after New York-based Rain鈥檚 Series A and brings total funding to $88.5 million.

4. , $50M, autonomous ships: Boston-based Blue Water Autonomy, a startup designing and building unmanned ships for the , closed on $50 million in Series A funding led by 鈥檚 Blue Water said it plans to use the funding to build and deploy its first long-range, full-sized autonomous ship next year.

5. , $50M, health care AI: Assort Health, a San Francisco-based provider of AI patient communication tools for specialty healthcare providers, reportedly about $50 million in a Series B round at a valuation of $750 million.

6. , $34M, photonics: OpenLight, based in Goleta, California, is a developer of a silicon photonics platform for semiconductor design which landed $34 million in a Series A co-led by and .

7. (tied) , $30M, fintech: New York-based Atomic, provider of an embedded investing platform for fintechs and financial institutions, snagged $30 million in a growth round led by and .

7. (tied) , $30M, vertical AI: San Mateo, California-based Aurasell, developer of an AI-native CRM platform, locked up $20 million in seed funding backed by , and .

7. (tied)聽, $30M, biotech: Leal Therapeutics, a Massachusetts-based developer of therapeutics for patients living with neuropsychiatric or neurodegenerative disorders, a $30 million Series A financing led by ‘ .

10. , $28M, appliances: Copper, a developer of appliances with integrated battery storage, scored $28 million in a Series A financing consisting of equity and debt that was led by . The Berkeley, California-based startup鈥檚 first product offering is a stainless steel range and oven called 鈥淐harlie.鈥�

Methodology

We tracked the largest announced rounds in the SA国际传媒 database that were raised by U.S.-based companies for the period of Aug. 23-29. Although most announced rounds are represented in the database, there could be a small time lag as some rounds are reported late in the week.