The Week’s 10 Biggest Funding Rounds: Largest Financings Went To Defense, Wearables, Energy And Security

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 Crunchbase Megadeals Board.

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 deal roundup here.

Startup investors kept up the busy dealmaking pace this week with a number of big rounds. Top among them was a $1.75 billion Series D for Saronic, developer of autonomous vessels. Other big funding recipients hailed from sectors including fitness wearables, energy tech, cybersecurity and AI infrastructure, among others.

1. Saronic, $1.75B, autonomous ships: Austin-based Saronic, a defense tech startup focused on autonomous sea vessels, raised $1.75 billion in Series D funding, bringing total funding to around $2.6 billion. Kleiner Perkins led the round, which set a $9.25 billion valuation for the  company, more than double its Series C level in 2025.

2. Whoop, $575M, fitness wearables: Whoop, a provider of wearable fitness technology and a subscription platform that tracks physiological data, secured $575 million in Series G funding. Collaborative Fund led the financing,which set a $10.1 billion valuation for the Boston-based company.

3. Valar Atomics, $450M, nuclear energy: El Segundo, California-based nuclear energy startup Valar Atomics, raised fresh capital at a valuation of $2 billion, according to a Bloomberg article citing unnamed sources. The financing reportedly included $340 million in equity funding and $110 million in debt.

4. EnerVenue, $300M, battery technology: EnerVenue, a developer of grid-scale energy storage technology, says it closed on a $300 million extension of its Series B preferred round led by Full Vision Capital. The Fremont, California-based company also appointed a new chief executive officer, Henning Rath.

5. Tenex.AI, $250M, cybersecurity: Sarasota, Florida-based AI-enabled cybersecurity startup Tenex picked up $250 million in Series B funding led by Crosspoint Capital Partners. The company said it plans to use the funds to hire more than 250 people and supplying them with AI technology that makes them “ten times more efficient.”

6. Also, $200M, micromobility: Also, an electric mobility company spun out of Rivian, raised $200 million in a Series C round ​backed by Greenoaks, DoorDash, and Prysm Capital. The Palo Alto, California-based startup’s product lineup includes bikes, small autonomous EVs for deliveries, and associated gear.

7. Starcloud, $170M, space tech: Starcloud, a space infrastructure startup focused on building orbital data centers, secured $170 million in Series A funding led by Benchmark and EQT. The financing sets a $1.1 billion valuation for the Redmond, Washington-based company, making it the fastest Y Combinator alum to achieve unicorn status after demo day, which was 17 months ago.

8. ScaleOps, $130M, cloud infrastructure: New York-based cloud and AI infrastructure startup ScaleOps landed $130 million in Series C funding. Insight Partners led the financing, which set  a valuation of over $800 million for the 4-year-old company.

9. Ambrosia Biosciences, $100M, biotech: Boulder, Colorado-based Ambrosia Biosciences, a developer of next-generation oral therapeutics for obesity and related cardiometabolic diseases, picked up $100 million in Series B funding led by Blue Owl, Redmile Group and Deep Track Capital.

10. OpenFX, $94M, money transfer: OpenFX, provider of a platform to move money across borders, secured $94 million in Series A funding from backers including Accel, Atomico, M13, Northzone and Pantera Capital.

Methodology

We tracked the largest announced rounds in the Crunchbase database that were raised by U.S.-based companies for the period of March 28-April 3. 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.

Illustration: Dom Guzman