Big Money, Big Models: 55 U.S. AI Startups That Raised $100M+ in 2025

The AI industry kicked off 2025 with serious momentum and it never really let up.

In 2024, 49 U.S.-based AI startups raised funding rounds of $100 million or more, according to TechCrunch’s tracking. A handful of companies pulled in multiple mega-rounds, and seven startups crossed the $1 billion mark in a single raise.

Rather than cooling off, 2025 doubled down.

While fewer companies raised billion-dollar rounds compared to the year before, more startups raised multiple large rounds. Eight companies closed more than one mega-round in 2025, signaling sustained investor confidence across infrastructure, healthcare, developer tools, and foundational AI research.

And if the first weeks of 2026 are any indication, this wave isn’t slowing anytime soon. Elon Musk’s xAI announced a massive $20 billion Series E, and Sam Altman backed brain-computer interface startup Merge Labs closed a $250 million seed round with OpenAI leading the investment. It’s early, but all signs point to another blockbuster year ahead.

Below is a month by month look at every U.S. AI company that raised $100 million or more in 2025.

December 2025

December closed out the year with a surge of late-stage and eye-popping early-stage rounds.

• Mythic (Austin, TX), which builds power-efficient AI compute, raised a $125M venture round led by DCVC.
• Chai Discovery secured $130M in Series B funding, valuing the biotech AI startup at $1.2B.
• Fal, a generative media platform, raised a $140M Series D led by Sequoia, pushing its valuation past $4.5B.
• Unconventional AI stunned the market with a $475M seed round, valuing the one-year-old startup at nearly $4.5B.
• 7AI, a Boston-based cybersecurity AI company, raised $130M in a Series A led by Index Ventures.

November 2025

November was dominated by developer tools, media generation, and AI infrastructure.

• Genspark raised $275M in Series B funding at a $1.25B valuation.
• Luma AI closed a massive $900M Series C, valuing the company at $4B.
• Cursor, the viral AI coding platform, raised $2.3B, valuing the company at nearly $30B.
• Parallel, which builds web infrastructure for AI agents, raised $100M in Series A.
• Hippocratic AI added another $126M to its war chest in a Series C round, its second of the year.

October 2025

October saw some of the year’s largest rounds across enterprise, voice, and foundational AI.

• Fireworks AI raised $250M in Series C funding at a $4B valuation.
• Uniphore closed a $260M Series F, valuing the enterprise AI company at $2.5B.
• Sesame, a voice AI startup, raised $250M in Series B funding.
• OpenEvidence raised $200M in Series C, valuing the medical AI company at $6B.
• Lila Sciences raised $350M in Series A funding as it pursues science superintelligence.
• Reflection AI announced a $2B Series B led by Nvidia.
• EvenUp, which applies AI to personal injury law, raised $150M in Series E funding.

September 2025

September was one of the busiest months of the year, particularly for AI infrastructure and research labs.

Highlights included:

• Periodic Labs raising a $300M seed round
• Cerebras Systems closing a $1.1B Series G
• Groq raising $750M in Series D funding
• Cognition AI, creator of Devin, raising $400M at a $10.2B valuation
• Anthropic announcing a staggering $13B Series F, valuing the company at $183B

August January 2025 (Highlights)

The rest of the year featured steady mega-rounds across healthcare, legal tech, generative media, and AI infrastructure:

• OpenAI shattered records with a $40B round valuing the company at $300B
• Thinking Machines Lab raised $2B in seed funding
• Runway, SandboxAQ, Lambda, Together AI, Abridge, Harvey, and Eleven Labs all raised $100M+ rounds
• Multiple companies including Fal, Cursor, Anthropic, Abridge, and Harvey raised more than one mega-round during the year

The Big Picture

What stands out in 2025 isn’t just the size of the rounds it’s the breadth. Funding flowed not only to headline-grabbing foundation models, but also to infrastructure, healthcare automation, legal AI, voice, media generation, and developer tools.

If early 2026 deals are any signal, AI investment remains firmly in expansion mode. Whether the pace holds throughout the year remains to be seen but for now, the momentum is unmistakable.