U.S. AI Startups Raising $100M+ Funding in 2025: A Year of Mega-Rounds

The U.S. AI sector continues to attract massive investor interest in 2025. Already, the number of AI startups raising $100 million or more matches the total from 2024, with several companies securing multiple mega-rounds this year. Seven companies have raised rounds of $1 billion or more, signaling strong investor confidence in AI innovation across healthcare, enterprise, infrastructure, and generative AI.

Table of Contents

Notable Funding Highlights by Month

November

Anysphere (Cursor platform) – $2.3B round, valuation $29.3B (second round this year)
Parallel – $100M Series A, co-led by Index Ventures & Kleiner Perkins
Hippocratic AI – $126M Series C, valuation $3.5B

October

Fireworks AI – $250M Series C, valuation $4B
Uniphore – $260M Series F, valuation $2.5B
Sesame – $250M Series B, co-led by Sequoia & Spark Capital
OpenEvidence – $200M Series C, valuation $6B (second round this year)
Lila Sciences – $350M Series A (second round)
Reflection AI – $2B Series B (second mega-round)
EvenUp – $150M Series E, valuation $2B

September

Periodic Labs – $300M seed round
Cerebras Systems – $1.1B Series G, valuation $8.1B
Modular – $250M funding round
Distyl AI – $175M Series B, valuation $1.8B
Upscale AI – $100M seed round
Groq – $750M Series E, valuation $6.9B
Invisible Technologies – $100M fundraise, valuation $2B
Cognition AI – $400M Series C, valuation $10.2B
Baseten – $150M Series D, valuation $2.1B
Sierra – $350M, valuation $10B
You.com – $100M Series C, valuation $1.5B
Anthropic – $13B Series F, valuation $183B (second round this year)

August

EliseAI – $250M Series E, valuation $2.2B
Decart – $100M, valuation $3.1B

July

Fal – $125M Series C, valuation $1.5B
Ambience Healthcare – $243M Series C
Reka AI – $110M Series B, valuation $1B
Thinking Machines Lab – $2B seed round, valuation $12B
OpenEvidence – $210M Series B, valuation $3.5B
Harmonic – $100M Series B, valuation $875M

June

Abridge – $300M Series E, valuation $5.3B (second round this year)
Harvey – $300M Series E, valuation $5B (second round this year)
Tennr – $101M Series C, valuation $605M
Glean – $150M Series F, valuation $7.25B
Anysphere – $900M Series C, valuation $10B

May

Snorkel AI – $100M Series D, valuation $1.3B
LMArena – $100M seed, valuation $600M
TensorWave – $100M Series A

April

SandboxAQ – $450M Series E, valuation $5.7B
Runway – $308M Series D, valuation $3B

March

OpenAI – $40B funding, valuation $300B
Nexthop AI – $110M Series A
Insilico Medicine – $110M Series E, valuation $1B
Celestial AI – $250M Series C, valuation $2.5B
Lila Sciences – $200M seed round
Reflection.AI – $130M Series A, valuation $580M
Turing – $111M Series E, valuation $2.2B
Shield AI – $240M Series F, valuation $5.3B
Anthropic – $3.5B Series E, valuation $61.5B

February

Together AI – $305M Series B, valuation $3.3B
Lambda – $480M Series D, valuation $2.5B
Abridge – $250M Series D, valuation $2.75B
Eudia – $105M Series A
EnCharge AI – $100M Series B
Harvey – $300M Series D, valuation $3B

January

ElevenLabs – $180M Series C, valuation $3B
Hippocratic AI – $141M Series B, valuation $1.6B

💡 Summary:
2025 has emerged as a banner year for AI startups in the U.S., with multiple companies securing mega-rounds of $1 billion+, record-breaking valuations, and investors showing strong confidence across sectors from generative AI to healthcare, enterprise solutions, and AI infrastructure. Several companies, including Anthropic, Reflection AI, and Anysphere, have raised multiple rounds, demonstrating accelerating momentum in AI investment.