Monthly roundup · AI · September 2026

AI startup funding, September 2026: Crusoe's $3.9B Series F leads 195 rounds

By Millionrounds ResearchPublished 1 October 2026Updated 5 November 2026

We read 195 equity rounds in AI announced in September 2026, raising $27B between them: 55% of all the rounds we read that month and 70% of the money. The largest was Crusoe's $3.9B Series F, led by Valor Equity Partners and Atreides Management. The median seed round was $5.3M, against $7.0M over the last twelve months in AI; at Series A it was $20M. General Catalyst led the most rounds, with 5.

Equity rounds195in AI, 186 with an amount
Raised$27Bacross those rounds
Lead named87%of rounds say who led
Share of the month55%of rounds; 70% of the money

The biggest rounds

  1. 1CrusoeSeries F · United States · led by Valor Equity Partners, Atreides Management$3.9B
  2. 2Mistral AISeries D · France · led by Samsung Electronics$3.5B
  3. 3CognitionSeries E · United States · led by Andreessen Horowitz, Accel$2.0B
  4. 4InstinctSeries C · United States$1.0B
  5. 5Positron AISeries C · led by New Enterprise Associates, Valor Equity Partners$875M
  6. 6GroqGrowth · United States · led by Disruptive$750M
  7. 7Angle HealthSeries C · United States · led by Vitruvian Partners$600M
  8. 8TTEKEVERSeries D · United Kingdom · led by Baillie Gifford, UC Investments$580M
  9. 9HarveyGrowth · United States · led by Lightspeed Venture Partners, Diffusion$550M
  10. 10TemporalSeries E · United States · led by Lightspeed Venture Partners, Tiger Global Management$550M

Day by day

Equity rounds in AI announced each day of September. The busiest day was 15 September, with 19.

1 September30 September

By stage, against the year

Each stage's median this month beside its twelve-month median: the sector's own where we hold enough rounds for a benchmark, otherwise the one across all sectors.

Pre-seed34$2.0Mthis month$2.1M12 months here
Seed49$5.3Mthis month$7.0M12 months here
Series A38$20Mthis month$21M12 months here
Series B27$55Mthis month$55M12 months here
Series C20$150Mthis month$110M12 months here
Series D7$115Mthis month$147M12 months here
Growth14$300Mthis month$150M12 months here

The most active leads

Firms that led two or more of the month's rounds in AI.

Where

United States had the most AI rounds this month.

Against the month

  • Rounds, AI195
  • Rounds, all sectors357
  • Raised, AI$27B
  • Raised, all sectors$39B

The whole of September 2026

Other sectors in September

51 roundsFintech→39 roundsHealthcare→30 roundsBig Data & Analytics→27 roundsBiotech→25 roundsRobotics→24 roundsCybersecurity→23 roundsHardware & Electronics→22 roundsEnterprise Software→21 roundsSoftware→21 roundsEnergy→21 roundsConstruction→20 roundsHealthtech→20 roundsSaaS→19 roundsLogistics→17 roundsManufacturing→16 roundsCleantech→14 roundsAerospace & Space→14 roundsDefence Tech→13 roundsTelecoms→13 roundsSemiconductors→13 roundsClimate Tech→11 roundsAutomotive & EVs→10 roundsCloud→