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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 ½ûÂþÌìÌà Megadeals Board.

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

We took a break from covering the largest U.S. startup investments over Thanksgiving week, which was just as well, given that it was a predictably slow period for big deal announcements. Now, with just a few weeks left in 2025, things are picking up again.

Predictions market led the list after confirming its already widely reported $1 billion fresh financing. Other big rounds came from sectors including defense tech, AI infrastructure, cybersecurity and biotech.

1. , $1B, predictions market: A couple weeks ago, we included Kalshi in our Top 10 after the company reportedly secured $1 billion in fresh funding. Well, now it’s official, with from the fast-growing New York-based predictions marketplace. Crypto-focused investor led the financing, with participation from a long list of venture firms.

2. , $350M, defense tech: Castelion, a developer of hypersonic munitions, it raised $350 million in Series B financing led by and . The Torrance, California-based company was founded by alum in 2022.

3. , $300M, cloud data: New York-based Eon, a provider of cloud data backup technology for enterprise AI, $300 million in a Series D led by of . The round brings Eon’s total funding to $500 million since its founding less than two years ago and increases its valuation to $4 billion.

4. , $150M, health insurance: Curative, a startup that markets a free out-of-pocket health plan, picked up $150 million in a Series B round led by . The financing values the Austin-based company at $1.27 billion.

5. , $134M, health insurance: San Francisco-based Angle Health, an AI platform for healthcare benefits, closed on $134 million in Series B funding led by . The round included a combination of debt and equity, bringing total funding to nearly $200 million, according to the company.

6. (tied) , $130M, cybersecurity: 7AI, a developer of tools for scaling AI agents to do security work, pulled in $130 million in a Series A led by . The funding round comes just 10 months after the Boston-based company launched out of stealth mode.

6. (tied) , $130M, biotech: Protego Biopharma, a startup therapeutics that aims to reprogram protein folding to address multiple diseases and disorders, raised $130 million in Series B funding. and led the financing for the San Diego-based company.

8. , $120M, biotech: Lexington, Massachusetts-based Triana Biomedicines, developer of a molecular glue discovery platform, $120 million in Series B financing. and co-led the round.

9. , $105M, simulation testing: Antithesis, a developer of simulation testing tools for software systems, raised $105 million in Series A funding. led the financing for the Tysons Corner, Virginia-based startup.

10. , $100M, AI server chips: Axiado, developer of a chip designed to save space and power in artificial intelligence servers, secured $100 million in a Series C+ round. led the investment for the San Jose, California-based company.

Methodology

We tracked the largest announced rounds in the ½ûÂþÌìÌà database that were raised by U.S.-based companies for the period of Nov. 28-Dec. 5. 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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