US Startup Funding Overview – September 2025
Key Insights – September 2025
September 2025 marked an extraordinary month for US venture capital with $30.91B invested across 533 companies, showing a 281.6% increase from August 2025’s $8.19B and a remarkable 311.9% year-over-year increase from September 2024’s $7.5B. The monthly total was dominated by Anthropic’s record-breaking $13B Series F round, alongside continued massive investments in AI infrastructure, quantum computing, and robotics.
Artificial Intelligence dominated funding with an estimated $23.2B across AI-related companies (75% of total funding).
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Top Industries by Investment
| Industry | Total Funding | Deal Count | Avg. Deal Size |
|---|---|---|---|
| Artificial Intelligence (AI) | $23.22B | 224 | $103.7M |
| Software | $4.85B | 147 | $33.0M |
| Health Care | $2.12B | 99 | $21.4M |
| Quantum Computing | $1.08B | 3 | $360.0M |
| Information Technology | $980M | 105 | $9.3M |
Funding by Round Type
| Round Type | Total Funding | Deal Count | Avg. Deal Size | Median Deal Size |
|---|---|---|---|---|
| Early-Stage | $1.88B | 298 | $6.3M | $3.0M |
| Series A | $2.16B | 112 | $19.3M | $13.0M |
| Series B | $2.89B | 70 | $41.3M | $33.8M |
| Late-Stage | $23.97B | 53 | $452.2M | $104.0M |
Overall median deal size: $7.0M across all 533 transactions
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Detailed Analysis
Market Context
Total US startup funding in September 2025 reached $30.91B across 533 companies, representing a remarkable 281.6% increase from August 2025’s $8.19B and an extraordinary 311.9% surge compared to September 2024’s $7.5B. This historic month was anchored by Anthropic’s record-breaking $13B Series F round, which alone accounted for 42% of the month’s total funding.
Key Metrics
- Average deal size: $58.0M (increased from August’s $20.9M)
- Median deal size: $7.0M (showing healthy mid-market activity)
- Largest deal: Anthropic at $13.0B
- Funded companies: 533 (35.6% increase from August)
- AI funding share: 75.1% of total funding ($23.22B)
- Series B + Late-stage concentration: 86.9% of total funding
Industry Insights
Artificial Intelligence Infrastructure dominated the funding landscape with Anthropic’s $13B Series F leading a wave of massive AI investments. Cerebras Systems ($1.1B for AI chips), Databricks ($1.0B for data/AI platform), and Groq ($750M for inference chips) highlighted the infrastructure arms race supporting the AI boom.
Deep Technology Breakthroughs attracted significant capital with PsiQuantum securing $1.0B for quantum computing, Figure raising $1.0B for humanoid robotics, and Cognition landing $400M for AI development tools. These investments signal strong investor confidence in transformative hardware and fundamental technology advances.
Geographic Concentration intensified with San Francisco capturing 100 deals (18.8% of total) and New York securing 79 deals (14.8%), together accounting for over one-third of all transactions. The Bay Area’s dominance in mega-rounds likely captured over 60% of total funding value.
Notable Trends
- Mega-Round Concentration: The top 10 deals totaled $21.4B (69.2% of all funding), showing extreme capital concentration
- Stage Divergence: Late-stage deals averaged $452.2M while Early-stage averaged just $6.3M—a 72x difference
- AI Dominance: 224 AI-related companies secured funding, representing 42% of all deals but 75% of capital
- Sustained Early-Stage Activity: Despite mega-round dominance, 298 Early-stage deals showed healthy ecosystem fundamentals
- Developer Platform Growth: Vercel ($300M), Sierra ($350M), and Kraken ($500M) highlighted continued platform investments
