September 2025 saw over $10 billion flow into AI startups, with a concentrated group of venture capital firms leading the charge. From infrastructure plays to enterprise applications, these investors shaped the future of artificial intelligence. Here’s who wrote the biggest checks and backed the most promising AI companies this month.
Most Active AI Investors in September 2025
1. Insight Partners
Notable September Investments:
- Filevine ($400M Series E – Legal AI)
- Inspiren ($100M Series B – Healthcare AI)
- Anthropic ($13B Series F – Foundational AI)
Total September AI Investments: $500M+ across 3 deals
New York-based Insight Partners, founded in 1995 by Jeff Horing and Jerry Murdock, continued its aggressive AI enterprise software strategy in September. The firm manages $90+ billion across growth equity and private equity funds, making it one of the world’s largest software investors.
Insight focuses on AI companies with proven enterprise traction, strong unit economics, and revenue over $10 million. The firm typically invests $20-500 million in Series B through pre-IPO rounds, targeting companies that use AI to transform traditional business processes.
Beyond September deals, Insight backs AI companies including Wiz (cybersecurity AI), Recorded Future (threat intelligence), and Celonis (process mining). The firm’s ScaleUp program provides hands-on operational support to portfolio companies.
Jeff Horing leads AI investments with support from Deven Parekh and Nikhil Sachdev, who focus on enterprise software and vertical SaaS companies.
2. Khosla Ventures
Notable September Investments:
- Distyl AI ($175M Series B – Enterprise AI Consulting)
- Aleph ($29M Series B – FP&A AI)
- Multiple undisclosed AI seed rounds
Total September AI Investments: $200M+ across 5+ deals
Founded in 2004 by Sun Microsystems co-founder Vinod Khosla, Khosla Ventures has become synonymous with transformative AI investing. The firm manages $15+ billion and has backed AI pioneers including OpenAI (early investor), Anthropic, and over 50 AI-focused companies.
Khosla invests across all stages from seed to growth, focusing on “black swan” technologies that can create entirely new markets. The firm particularly targets AI infrastructure, foundational models, and AI-native enterprise applications. Typical check sizes range from $500K (seed) to $100M+ (growth).
OpenAI, Anthropic, Glean, Writer, Zapier (AI features), and dozens of AI infrastructure startups. Khosla portfolio companies have raised $30+ billion in follow-on funding.
Vinod Khosla remains actively involved, with partners Kanu Gulati (AI/ML specialist), Alex Morgan, and Nima Rahmany leading AI investments.
3. Lightspeed Venture Partners
Notable September Investments:
- Distyl AI ($175M Series B – Co-lead)
- Anthropic ($13B Series F)
- Exa ($85M Series B – AI Search)
Total September AI Investments: $250M+ across 4 deals
Menlo Park-based Lightspeed, founded in 2000, manages $18+ billion across early and growth-stage funds. The firm has backed 8 AI unicorns and maintains one of the most active AI portfolios in venture capital.
Lightspeed invests from seed through growth stages ($1M-200M checks), focusing on AI infrastructure, developer tools, and vertical AI applications. The firm seeks founders with deep technical expertise and companies addressing large, underserved markets.
Anthropic, Glean ($2.2B valuation), Tome (AI presentations), and Cribl (data observability). Lightspeed’s AI portfolio companies collectively serve 100M+ users.
Ravi Mhatre (enterprise AI), Gaurav Gupta (consumer AI), and Nicole Quinn (fintech AI) lead AI investments, supported by 15+ investment professionals.
4. Fidelity Management & Research
Notable September Investments:
- Nscale ($1.1B Series B – AI Infrastructure)
- Empower Semiconductor ($140M+ Series D – AI Hardware)
- Anthropic ($13B Series F)
Total September AI Investments: $1.2B+ across 3 deals
Fidelity’s private investment arm has emerged as a major player in late-stage AI funding, leveraging its $4.5+ trillion in assets under management. The firm typically invests $50-500 million in growth and pre-IPO rounds.
Fidelity targets capital-intensive AI infrastructure plays and late-stage AI companies preparing for public markets. The firm seeks companies with clear paths to profitability, substantial revenue traction, and defensible technology moats.
OpenAI, Anthropic, SpaceX (AI-powered systems), Epic Games (AI-generated content), and numerous AI infrastructure companies. Fidelity often provides multiple rounds of funding to portfolio companies.
With crossover fund capability, Fidelity can support companies from late-stage private rounds through IPO and beyond, providing unique continuity.
5. Sequoia Capital
Notable September Investments:
- Juicebox ($30M Series A – Recruiting AI)
- Factory ($50M Series B – AI Coding Agents)
- Multiple undisclosed AI investments
Total September AI Investments: $80M+ across 3+ deals
Menlo Park’s Sequoia Capital, founded in 1972, manages $85+ billion and has backed more AI unicorns than any other firm. The firm’s AI portfolio includes OpenAI, Anthropic, and dozens of category-defining AI companies.
Sequoia invests across all stages through separate funds (Seed, Venture, Growth), writing checks from $100K to $1B+. The firm seeks “definitive founders” building transformative AI companies with massive market potential.
OpenAI, Anthropic, Harvey (legal AI), Glean, Writer, and Typeface. Sequoia’s AI portfolio companies represent 40%+ of the firm’s total portfolio value.
Roelof Botha (AI oversight), Pat Grady (enterprise AI), Stephanie Zhan (consumer AI), and Konstantine Buhler (AI infrastructure) lead investments across 30+ AI companies.
6. General Catalyst
Notable September Investments:
- Judi Health ($400M Series F)
- Anthropic ($13B Series F)
- Modular ($250M Series C)
Total September AI Investments: $650M+ across 3 deals
Boston-based General Catalyst, founded in 2000, manages $30+ billion focused on transformational technology companies. The firm has systematically built one of the strongest enterprise AI portfolios in venture capital.
General Catalyst invests $500K to $500M across seed through growth stages, focusing on AI companies transforming healthcare, fintech, and enterprise software. The firm seeks technical founders with domain expertise building “creation” companies.
Anthropic, Guardsquare (application security AI), AirTable (AI features), and dozens of vertical AI applications. General Catalyst’s Venture Creation Studio also incubates AI companies.
Hemant Taneja (CEO, healthcare AI focus), Niko Bonatsos (enterprise AI), and Kyle Doherty (fintech AI) lead investments with deep operational support.
7. NVIDIA (NVentures)
Notable September Investments:
- Nscale ($1.1B Series B)
- Cohere ($100M Series D)
- Factory ($50M Series B)
Total September AI Investments: $150M+ across 5+ deals
NVIDIA’s venture arm has become one of the most active strategic investors in AI, leveraging the company’s position as the dominant AI chip provider. NVentures invests across AI infrastructure, applications, and enabling technologies.
NVIDIA invests $5-100 million in companies building on or complementing NVIDIA’s AI platform. The firm provides not just capital but also technical support, early access to hardware, and integration with NVIDIA’s ecosystem.
Cohere, Snowflake, DataRobot, Hugging Face, and 50+ AI infrastructure companies. NVIDIA’s investments often signal technical validation and drive additional venture funding.
Portfolio companies gain direct access to NVIDIA’s chip roadmap, technical teams, and sales channels, creating significant competitive advantages.
8. Bessemer Venture Partners
Notable September Investments:
- Auterion ($130M Series B – Defense AI)
- Multiple AI seed and Series A rounds
Total September AI Investments: $140M+ across 4 deals
Founded in 1911, Bessemer is one of the oldest venture firms and has pivoted aggressively toward AI. The firm manages $20+ billion and has backed 145+ cloud companies, increasingly focused on AI applications.
Bessemer invests $1-100 million from seed through growth, focusing on “AI-native” companies built from the ground up around artificial intelligence. The firm’s “BVP Nasdaq Emerging Cloud Index” tracks public cloud companies, many with AI capabilities.
OpenAI (early investor), Jasper (content AI), Intercom (customer service AI), and Canva (design AI). Eight Bessemer AI portfolio companies have reached unicorn status.
Sameer Dholakia (cloud/AI), Ethan Kurzweil (AI infrastructure), and Kent Bennett (consumer AI) lead investments. Bessemer’s Centaur Program provides dedicated AI/ML engineering support.
9. Balderton Capital
Notable September Investments:
- Light ($30M Series A – Finance AI)
Total September AI Investments: $30M+ across 2 deals
London-based Balderton Capital, founded in 2000, manages $5+ billion focused on European technology companies. The firm has increasingly focused on AI applications, particularly those serving European and global markets.
Balderton invests $1-50 million from seed through Series B, focusing on European AI companies with global ambitions. The firm seeks strong technical teams building AI-native solutions for finance, enterprise software, and vertical applications.
Revolut (AI-powered fraud detection), ContentSquare (analytics AI), and emerging AI startups across Europe. Balderton provides European market expertise and US expansion support.
Bernard Liautaud (founding partner), James Wise (AI/ML focus), and Suranga Chandratillake (technical AI investments) lead the firm’s AI strategy.
10. NEA (New Enterprise Associates)
Notable September Investments:
- Factory ($50M Series B – AI Coding Agents)
Total September AI Investments: $50M+ across 2 deals
Menlo Park-based NEA, founded in 1977, manages $25+ billion and is one of the largest and most established venture firms. The firm has systematically built an AI portfolio focused on developer tools and enterprise applications.
NEA invests $5-100 million from Series A through growth stages, targeting AI companies with strong product-market fit and expanding customer bases. The firm prefers companies building tools for developers and knowledge workers.
DataRobot (enterprise AI), Databricks (AI/ML platform), Plaid (fintech with AI features), and Duolingo (AI-powered learning). NEA’s AI portfolio companies serve millions of developers and enterprises.
Tony Florence (enterprise software), Rick Yang (frontier tech), and Carmen Chang (AI applications) lead AI investments with 40+ years combined experience.
Emerging AI Investors to Watch (Active in September)
Wellington Management
Led Judi Health’s massive $400M Series F in September, bringing institutional capital and public market expertise to late-stage AI healthcare companies. The firm is increasingly active in growth-stage AI investments.
TPG
Led Tide’s $120M Series F, demonstrating increased focus on AI-enabled fintech and enterprise software. TPG brings private equity discipline and operational expertise to scaling AI companies.
Riverwood Capital
Exclusively led AppZen’s $180M Series D in September, focusing on proven B2B AI software with strong enterprise traction and revenue growth. The firm specializes in global software companies.
US Innovative Technology Fund
Led Modular’s $250M Series C, founded by billionaire Tom Tull specifically to invest in transformative AI infrastructure. The fund writes large checks ($50M+) for capital-intensive AI companies.
Aker ASA
Norwegian conglomerate led Nscale’s record $1.1B Series B, representing European industrial capital’s entry into AI infrastructure. Signals growing interest from non-traditional VC sources.
Blue Owl Capital
Participated in Nscale’s $1.1B round, bringing alternative asset management capital (manages $150B+) to AI infrastructure. Increasingly active in late-stage AI deals.
CVS Health Ventures
Led AmplifAI’s $33.7M Series B in September, demonstrating strategic corporate interest in vertical AI applications. CVS seeks AI solutions applicable to healthcare operations.
BlueYard Capital
Led Corintis’s $24M Series A for AI chip cooling technology, focusing on critical AI infrastructure components. The Berlin-based firm backs European deep-tech AI companies.
Investment Trends: September 2025
1. Infrastructure Dominance
48% of September AI funding went to infrastructure companies (data centers, chips, compute platforms), reflecting the critical need for AI-ready hardware and software stacks.
2. Enterprise Focus
72% of deals targeted B2B applications, showing investors prefer proven enterprise revenue over consumer experiments.
3. Mega-Rounds Concentrated
The top 5 deals ($13B Anthropic, $1.1B Nscale, $400M Filevine, $400M Judi Health, $250M Modular) represented 93% of total September AI funding.
4. Strategic Investors Rise
Corporate VCs (NVIDIA, Google, Salesforce, Dell) participated in 40% of deals, up from 25% in 2024, providing validation and strategic value beyond capital.
5. Later Stage Preference
Average deal size reached $280 million in September, with 65% of capital going to Series C+ rounds as investors favor proven businesses.
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