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

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

2. Wugen, $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 Fidelity. Seven-year-old Wugen plans to use the financing in part to fund clinical trials.

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

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

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

6. OpenLight, $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 Xora Innovation and Capricorn Investment Group.

7. (tied) Atomic, $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 Aquiline Capital Partners and Brewer Lane Ventures.

7. (tied) Aurasell, $30M, vertical AI: San Mateo, California-based Aurasell, developer of an AI-native CRM platform, locked up $20 million in seed funding backed by N47, Menlo Ventures and Unusual Ventures.

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

10. Copper, $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 Prelude Ventures. The Berkeley, California-based startup’s first product offering is a stainless steel range and oven called “Charlie.”

Methodology

We tracked the largest announced rounds in the Crunchbase 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.