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 deal roundup here.

Venture investors’ thirst for AI isn鈥檛 close to quenched yet. That鈥檚 the takeaway from this week鈥檚 lineup of large U.S. funding rounds, which was mostly a mix of AI pure-plays and companies with a heavy focus on the technology.

The week鈥檚 largest round however, a $600 million financing for drone delivery provider Zipline, offered evidence that investors are also keen on platforms and technologies with applications in the physical world. The second-largest round, a $480 million seed deal for upstart AI lab Humans&, meanwhile, showed there鈥檚 also still appetite for ultra-ambitious newcomers.

1. , $600M, drones: Drone delivery unicorn Zipline it closed on over $600 million at a $7.6 billion valuation from investors including , , and . South San Francisco, California-based Zipline also says it expects to expand into at least four new states this year, with initial plans to begin service in Houston and Phoenix.

2. , $480M, AI: Humans&, an AI lab working to apply the technology in ways that are centered 鈥渁round people and their relationships with each other,鈥� secured $480 million in seed funding. The company was founded in September by top researchers from , , , and .

3. , $300M, AI infrastructure: AI infrastructure startup Baseten reportedly $300 million with backing from , and . The financing set a $5 billion valuation for the 7-year-old, San Francisco-based company.

4. , $250M, medical AI: OpenEvidence, an AI platform for doctors, announced that it picked up $250 million in a Series D funding round that doubled its valuation to $12 billion. and co-led the round, which marks the fourth fundraise for the Miami-based startup in less than a year.

5. , $215M, rare earth magnets: San Marcos, Texas-based Noveon Magnetics, a manufacturer of sintered rare earth permanent magnets, it secured $215 million in Series C funding, including $200 million from . The money will go toward expanding the company鈥檚 rare earth magnet manufacturing capacity.

6. , $200M, AI infrastructure: AI networking infrastructure startup Upscale AI $200 million in Series A funding led by , and . The financing set a valuation of more than $1 billion for the Santa Clara, California-based company, which was founded less than two years ago.

7. (tied) , $150M, online tutoring: Language learning marketplace Preply raised $150 million in Series D funding led by . The financing reportedly sets a $1.2 billion valuation for the 14-year-old, Brookline, Massachusetts-based company.

7. (tied) , $150M, AI inference: Inferact, a startup founded by creators and maintainers of open-source LLM inference engine vLLM, announced its launch along with $150 million in initial funding. and led the financing, which set an聽 $800 million valuation for the company.

7. (tied) , $150M, cybersecurity: Security provider Claroty picked up $150 million in Series F funding led by . The 11-year-old company, founded in Israel and now headquartered in New York, has raised close to $900 million in equity funding to date, per 附近上门 data.

10. , $115M, geothermal energy: Salt Lake City-based Zanskar, a startup applying AI to geothermal exploration, raised $115 million in Series C funding led by and joined by a long list of new and existing investors.

Methodology

We tracked the largest announced rounds in the 附近上门 database that were raised by U.S.-based companies for the period of Jan. 17-23. 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.

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For starters, global investment in clean technologies is running high. Spending on the category, which includes renewables, grids, low-emissions power sources, and energy efficiency, is on course to hit $2.2 trillion this year, . That鈥檚 twice what is invested in fossil fuels.

Venture capital is pretty flush as well. Global venture funding in the first three quarters of the year topped $300 billion, the highest level in years. Moreover, a record share of this funding is going to companies focused on AI, a technology whose immense power demands will require massive new energy infrastructure.

The environmental case for cleantech is also only getting more urgent. Concentrations of greenhouse gases and ocean heat content both reached record levels this year, the World Meteorological Organization, with the past three years being the warmest on record.

All this is to say that the macro picture, a bullish one for cleantech investment, contrasts sharply with the actual numbers, which show this was an unusually weak year for the space.

Lowest funding in years

How weak? This year, investors put just over $24 billion across all stages into startups in 附近上门’s cleantech-, electric vehicle- and sustainability-related categories. That鈥檚 by far the lowest annual total in five years.

Quarter over quarter, the picture looks sunnier. Cleantech investment actually hit a low in Q1 and has since been moving higher.

One interpretation is that U.S. investors paused on some dealmaking around Q1. With the incoming administration taking a hostile stance to the administration鈥檚 cleantech- and climate-friendly subsidies and policies, startups and their backers needed to recalibrate strategy for an altered political environment. Once that happened, the pace picked up some.

Some of the year鈥檚 largest rounds, meanwhile, are for companies in sectors with fairly broad support across the political spectrum. In this category is nuclear 鈥� both fusion and fission聽1 鈥� which was a particularly popular investment theme. We also saw good-sized deals around geothermal power, energy storage and electric aircraft.

Largest rounds

For a broader sense of where big-ticket investment was going, we put together a list of 12 of the largest cleantech-, EV- and sustainability-related funding rounds of 2025.

Clearly, investors were still enthused about backing jumbo-sized rounds in some cases.

Case in point: The leading funding recipient this year was Austin鈥檚 , which provides battery backup power for residential properties. The 3-year-old company landed $1.2 billion across two rounds this year, with as a repeat lead backer.

The next three biggest rounds, notably, were all for startups focused on nuclear power. Among them, the standout for funding was , which raised $863 million in an August Series B2 round. The Devens, Massachusetts-based company also said it is moving closer to being the first in the world to commercialize fusion power.

Nuclear fission is also a popular category for venture investors of late. In this cohort, , which develops small modular nuclear reactors and nuclear fuels, was another power fundraiser. The Rockville, Maryland, company secured a $700 million Series D in late November led by . And nuclear startup also landed a huge follow-on financing this summer, picking up $650 million, with 鈥檚 as a backer.

Battery investment, on the other hand, has been less robust. Investors braced for a heavy loss last year when Swedish EV battery maker , one of the most heavily funded companies in the space, initially filed for bankruptcy.

Still, deals were getting done. Besides Base Power, there were three other battery-related companies on our top rounds list for 2025. These were Dutch battery storage startup , Woodinville, Washington-based silicon battery material producer , and battery recycling company .

Perking up at year鈥檚 end

Probably the most encouraging signal for cleantech investment is it closed 2025 in a much stronger position than when it began the year. Given that drivers of demand are only strengthening, it looks reasonable to be optimistic about a continued rise.

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Related reading:

• 附近上门 Sector Snapshot: Cleantech Isn鈥檛 Having A Great Year

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