This Week’s 10 Biggest U.S. Startup Funding Rounds: Three $1B+ Deals

The week’s largest announced U.S. startup rounds were led by Hadrian, Base Power and Valar Atomics, each securing financings of $1 billion or more. Hadrian raised $1.37 billion in Series D funding for highly automated factories, with the financing setting a $7.87 billion valuation. Base Power secured $1 billion for residential battery energy storage systems at a $13 billion post-money valuation, while Valar Atomics closed $1 billion in Series B funding for nuclear energy technology and infrastructure.

AI-related infrastructure remained prominent among the largest rounds. Lumilens emerged from stealth with more than $700 million in new funding for its AI infrastructure connectivity platform. Volta, a developer of AI cloud infrastructure, also emerged from stealth and said it raised a Series A at a $2.4 billion valuation, while HappyRobot raised $150 million for an agentic AI platform geared toward enterprises in logistics, financial services, utilities and manufacturing.

The week’s biggest financings were not limited to AI and energy. Whatnot raised $545 million in Series G funding for its live shopping marketplace, while Mariana Minerals picked up $310 million in Series B funding for software-focused critical minerals projects. Horizon3 announced a $250 million Series E in cybersecurity, and LifeMine Therapeutics secured $188 million in Series E funding for drug discovery work tied to transplantation and immunology therapies.

Crunchbase News tracked the largest announced rounds in the Crunchbase database raised by U.S.-based companies for the period of Aug. 1-7. The roundup notes that most announced rounds are represented in the database, though some may appear with a small time lag if reported late in the week. Readers tracking large venture deals can use the list as a snapshot of where major private-market checks are concentrating across sectors.