US startups raised $27.89B across 754 rounds in September 2026, up 54% from August’s $18.1B and 9.8% below September 2025’s $30.91B. Four rounds of $1B or more, led by Crusoe’s $3.9B, took $9.90B, or 36% of the month. Late-Stage rounds drew $19.84B, about double August’s $9.81B, as AI infrastructure, space and defense companies raised at scale.
September 2026 US Funding Highlights
- Four rounds of $1B or more, against two in August: Crusoe ($3.9B), The Boring Company ($3.0B), Cognition ($2.0B) and Stoke Space ($1.0B) together raised $9.90B.
- 53 rounds of $100M or more took $20.81B, or 75% of September capital.
- AI compute and networking infrastructure was the deepest pool: Crusoe, Positron ($875M), Gimlet Labs ($300M), Celero ($275M), GMI Cloud ($223M) and Cornelis Networks ($205M) raised $5.78B.
- Space and defense companies Stoke Space, Mach Industries ($600M) and Impulse Space ($308M) raised $1.91B.
- California took $9.58B, or 34% of the total. Colorado ($4.32B, almost all Crusoe) and Texas ($4.17B, led by The Boring Company and Island) ranked second and third.
- New York captured 11.2% of US capital, up from 4.8% in August.
SummitPoint OS is the operating system for venture, guided by Frank. Hand him the work.
Venture runs on databases you search and spreadsheets you maintain. SummitPoint OS is one workspace for founders, investors and Industry Partners, and Frank, SummitPoint’s agentic AI analyst, does the work: builds the investor pipeline and writes the briefing on every name, screens the inbound deal against your thesis, watches every founder in your program, and shows you what he did.
US Funding by Stage: September 2026
| Stage | Rounds | Capital | Share | Largest Round |
|---|---|---|---|---|
| Late-Stage | 69 | $19.84B | 71.2% | Crusoe ($3.90B) |
| Series B | 54 | $3.32B | 11.9% | Gimlet Labs ($300M) |
| Series A | 119 | $2.97B | 10.6% | Solstice Oncology ($225M) |
| Early-Stage | 512 | $1.75B | 6.3% | Physical Superintelligence ($58M) |
| Total | 754 | $27.89B | 100.0% |
Top 10 US Funding Rounds: September 2026
| # | Company | Amount | Round | Investors |
|---|---|---|---|---|
| 1 | Crusoe AI infrastructure and cloud |
$3.90B | Series F | Atreides, Mubadala Capital, Valor Equity Partners |
| 2 | The Boring Company Tunnel transportation systems |
$3.00B | Series D | Valor Equity Partners, Sequoia Capital, Andreessen Horowitz |
| 3 | Cognition AI software engineering |
$2.00B | Series E | Andreessen Horowitz, Accel, Founders Fund |
| 4 | Stoke Space Reusable launch vehicles |
$1.00B | Series E | Point72 Ventures, Spark Capital |
| 5 | Positron AI inference chips |
$875M | Series C and C-1 | NEA, Atreides, Valor Equity Partners |
| 6 | Mach Industries Defense manufacturing |
$600M | Series C extension | Ribbit, Infinite Capital, Sequoia Capital |
| 7 | Harvey AI for law firms |
$550M | Series H | Diffusion, Lightspeed, Sequoia Capital |
| 8 | Temporal Technologies Open-source workflow platform |
$550M | Series E | Lightspeed, Wellington, Goldman Sachs Alternatives |
| 9 | Cyera AI-native data security |
$400M | Series G | Goldman Sachs Growth Equity |
| 10 | Island Enterprise browser security |
$400M | Series F | Evolution Equity Partners, Sequoia Capital, Coatue |
The top 10 rounds totaled $13.28B, or 48% of September capital.
September 2026: The Month in Detail
Late-Stage: 69 rounds, $19.84B
Late-Stage rounds took 71% of September capital. Crusoe’s $3.9B Series F, co-led by Atreides, Mubadala Capital and Valor, topped the month, followed by The Boring Company’s $3.0B Series D and Cognition’s $2.0B Series E, led by Andreessen Horowitz and Accel. Stoke Space raised $1.0B, Positron $875M across a Series C and C-1 led by NEA, and Mach Industries $600M as an extension of its Series C. Harvey and Temporal Technologies each raised $550M, while Island and Cyera each raised $400M.
Series B: 54 rounds, $3.32B
Gimlet Labs led the stage with $300M from Andreessen Horowitz, followed by Medici Brands ($250M), GMI Cloud ($223M) and General Intuition ($220M). Arcee AI raised $150M, Mazama Energy $135M for geothermal systems and micro1 $100M.
Series A: 119 rounds, $2.97B
Solstice Oncology raised $225M, led by RA Capital Management, the largest Series A of the month. TAR ($120M, data center power), BrainChild Bio ($116M), Maven Robotics ($100M) and Delos Data ($100M, AI interconnect hardware) followed, with Volantis ($88M) and Go.AI ($85M) close behind.
Early-Stage: 512 rounds, $1.75B
Early-Stage was by far the most crowded stage, with 512 rounds and just 6% of capital. The largest seed rounds went to Physical Superintelligence ($58M), Hang Ten Systems ($53M), Bluecore Energy ($50M) for small modular nuclear reactors, SciFin ($44M) and Noetive ($41M).
US Funding by Sector: September 2026
AI infrastructure set the pace. Crusoe, Positron, Gimlet Labs, Celero, GMI Cloud and Cornelis Networks raised $5.78B between them across compute, chips and networking, and Cognition ($2.0B), Harvey ($550M) and Snorkel AI ($350M) added $2.90B on the software side. Space and defense raised $1.91B across Stoke Space, Mach Industries and Impulse Space, whose $308M was an extension of its Series D. Health was led by Enveda ($311M), Encoded Therapeutics ($275M), Precision Neuroscience ($250M), Solstice Oncology ($225M) and BrainChild Bio ($116M), which together raised $1.18B. In cybersecurity, Island and Cyera each raised $400M. Beyond AI, The Boring Company’s $3.0B was the largest round outside it.
NYC vs. US: September 2026
| Metric | NYC | US | NYC Share |
|---|---|---|---|
| Capital Raised | $3.14B | $27.89B | 11.2% |
| Rounds | 59 | 754 | 7.8% |
| Change vs. Sep 2025 (capital) | +49% | -9.8% | |
| Change vs. Aug 2026 (capital) | +274% | +54% |
By Stage
| Stage | NYC Rounds | US Rounds | NYC Share | NYC Capital | US Capital | NYC Share |
|---|---|---|---|---|---|---|
| Late-Stage | 11 | 69 | 15.9% | $1.87B | $19.84B | 9.4% |
| Series B | 9 | 54 | 16.7% | $771.0M | $3.32B | 23.2% |
| Series A | 13 | 119 | 10.9% | $310.1M | $2.97B | 10.5% |
| Early-Stage | 26 | 512 | 5.1% | $187.1M | $1.75B | 10.7% |
| Total | 59 | 754 | 7.8% | $3.14B | $27.89B | 11.2% |
SummitPoint OS is the operating system for venture, guided by Frank. Hand him the work.
Venture runs on databases you search and spreadsheets you maintain. SummitPoint OS is one workspace for founders, investors and Industry Partners, and Frank, SummitPoint’s agentic AI analyst, does the work: builds the investor pipeline and writes the briefing on every name, screens the inbound deal against your thesis, watches every founder in your program, and shows you what he did.
Looking Ahead: US Startup Funding in Q4 2026
Q3 closed at about $65.43B, with September’s $27.89B following July’s $19.44B and August’s $18.1B. September’s leaders were concentrated in AI infrastructure, space and defense, and Q4 will show whether rounds of this size spread to other sectors or stay concentrated in a few. Explore every round at the AlleyWatch funding index.
Methodology
Figures come from AlleyWatch’s US startup funding data and use disclosed round sizes. Undisclosed rounds are excluded, as are corporate rounds, private equity and debt. Early-Stage covers Pre-Seed, Seed, Angel, Accelerator and Incubator rounds, Series A and Series B are reported individually, and Late-Stage covers Series C and later. Year-over-year and month-over-month comparisons use previously published AlleyWatch totals.
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