October 2025 was a huge month for AI funding. Investors put billions of dollars into AI companies building everything from coding tools to legal software. The biggest names in venture capital made massive bets on AI’s future. Here’s who invested the most and which AI companies got funded this month.
Most Active AI Investors in October 2025
1. Nvidia (NVentures)
Notable October Investments:
- Poolside ($500M-$1B investment – AI Coding Platform)
- Reflection AI ($2B Series B – Open Source AI)
- Fireworks AI ($250M Series C – AI Inference)
Total October AI Investments: $1.75B+ across 5+ deals
Nvidia’s investment arm became one of the biggest players in AI funding. In October, the company put up to $1 billion into Poolside, an AI coding startup. This would make Poolside worth $12 billion—four times more than before.
Nvidia also joined Reflection AI’s huge $2 billion funding round. The chip giant backed Fireworks AI too. Nvidia’s strategy is smart: invest in AI companies that will buy their chips later.
Portfolio companies get more than just money. They get early access to Nvidia’s newest chips, help from their engineers, and instant credibility. In 2025, Nvidia invested in 50 different AI companies—more than all of 2024.
Key Investment Focus: AI infrastructure, foundational models, coding tools, and any AI that needs powerful computer chips.
Strategic Advantage: Companies that get Nvidia funding gain access to their chip technology, expert teams, and sales networks. This gives them a huge edge over competitors.
2. Andreessen Horowitz (a16z)
Notable October Investments:
- Harvey ($150M Series D – Legal AI)
- Reducto ($75M Series B – Document AI)
- Kaizen ($21M Series A – Government Software)
Total October AI Investments: $250M+ across 5+ deals
Andreessen Horowitz (a16z) kept up its fast pace of AI investing in October. The firm led Harvey’s funding round, valuing the legal AI startup at $8 billion. Harvey got three major funding rounds just in 2025—showing how fast AI companies can grow.
The firm put $75 million into Reducto, which uses AI to read documents. Reducto processes nearly one billion pages every month. a16z also invested in Kaizen, showing interest in AI for government use.
Founded in 2009, a16z manages over $45 billion. The firm plans to raise a record $20 billion fund just for AI—the biggest venture fund ever (except for SoftBank’s Vision Funds).
Investment Philosophy: a16z looks for strong founders building AI that can dominate their markets. They invest at every stage—from $500,000 for new startups to $500 million for growing companies.
Portfolio Highlights: OpenAI, Anthropic, Harvey, Mistral, and over 100 AI companies. AI investments now make up over 40% of everything a16z owns.
3. Sequoia Capital
Notable October Investments:
- Reflection AI ($2B Series B – co-investor)
- Fireworks AI ($250M Series C – follow-on)
- Multiple undisclosed AI investments
Total October AI Investments: $150M+ across 4+ deals
Sequoia Capital joined Reflection AI’s huge $2 billion funding round led by Nvidia. The firm also gave more money to Fireworks AI as the company grew to a $4 billion value.
Sequoia manages $85 billion and has backed more AI unicorns (companies worth over $1 billion) than any other investor. The firm just announced $950 million in new funds just for early-stage AI startups.
Here’s where Sequoia really helps: they set up a meeting between Reflection AI and Nvidia’s CEO Jensen Huang. That meeting led to Nvidia investing $500 million. This shows how Sequoia does more than just give money—they open important doors.
Investment Strategy: Sequoia helps companies grow by providing advice and connections. They look for technical founders who deeply understand their field and are building AI for huge markets.
Notable AI Portfolio: OpenAI, Anthropic, Harvey, Glean, Writer, Together AI, and Reflection AI. Companies backed by Sequoia make up over $7 trillion of the Nasdaq stock market.
4. Bessemer Venture Partners
Notable October Investments:
- Legora ($150M Series C – Legal AI, led the round)
- ChipAgents ($21M Series A – Semiconductor Design AI)
- Multiple AI seed and Series A rounds
Total October AI Investments: $180M+ across 5+ deals
Bessemer stood out in October by leading Legora’s $150 million funding round. Legora is a Swedish legal-AI company now worth $1.8 billion. This is one of the biggest legal-tech investments in European history.
Founded way back in 1911, Bessemer is one of the oldest investment firms. But they’ve recently gone all-in on AI. The firm manages $20 billion and has backed 145+ cloud companies. Now they focus on “AI-native” businesses—companies built with AI from day one.
Bessemer also invested in ChipAgents, which uses AI to design computer chips. Other chip companies like Micron and MediaTek joined this investment too.
Investment Focus: AI-powered enterprise software from early stage through growth ($1 million to $100 million investments). They look for companies with proven customers and good business models.
Portfolio Strategy: Bessemer’s Centaur Program gives free AI and machine learning engineering help to their portfolio companies.
5. Lightspeed Venture Partners
Notable October Investments:
- Fireworks AI ($250M Series C – co-led)
- Reflection AI ($2B Series B – co-investor)
- General Intuition ($134M seed – co-investor)
Total October AI Investments: $300M+ across 6+ deals
Lightspeed had a busy October. They co-led Fireworks AI’s $250 million funding round with Index Ventures. Fireworks helps companies use open-source AI models—a growing trend in the industry.
Lightspeed manages $31 billion and has backed 8 AI unicorns. The firm just changed its structure to invest in more types of assets, not just startups.
They also invested in General Intuition’s $134 million seed round. That’s a huge amount for such an early-stage company. General Intuition builds AI that understands space and movement—think AI for robots and drones.
Investment Approach: Lightspeed invests from $1 million to $200 million. They look for technical founders building AI infrastructure, developer tools, and specialized applications.
Key AI Holdings: Anthropic, Glean, Fireworks AI, Reflection AI, and many AI infrastructure companies serving over 100 million users.
6. General Catalyst
Notable October Investments:
- Legora ($150M Series C – co-investor)
- General Intuition ($134M seed – co-led)
- Reflection AI ($2B Series B – co-investor)
Total October AI Investments: $250M+ across 4+ deals
General Catalyst made smart October bets across both AI infrastructure and applications. They joined Legora’s $150 million round, backing AI that helps lawyers work faster.
Managing $30 billion, General Catalyst has built one of the best enterprise AI portfolios. They co-led General Intuition’s $134 million seed round with Khosla Ventures—one of the largest early-stage AI investments ever.
The firm looks for “creation” companies—startups building game-changing businesses with technology that’s hard to copy. They invest from $500,000 to $500 million at any stage. Healthcare, fintech, and enterprise software are their main targets.
Strategic Focus: AI companies changing critical industries, led by technical founders who really know their field. General Catalyst’s Venture Creation Studio even starts AI companies from scratch.
Portfolio Leadership: Anthropic, Guardsquare, AirTable (with AI features), and many specialized AI applications. CEO Hemant Taneja personally leads healthcare AI investments.
7. Felicis
Notable October Investments:
- Mercor ($350M Series C – led the round)
- Multiple AI seed and Series A rounds
Total October AI Investments: $350M+ across 3+ deals
Felicis made October’s boldest single bet. They led Mercor’s $350 million funding round, valuing the AI talent marketplace at $10 billion. Just earlier in 2025, Mercor was worth only $2 billion—a 5x jump.
Mercor’s story is amazing: from college dorm room to $10 billion in under two years. The platform connects AI researchers and engineers with tech companies. Over 30,000 contractors use it, earning an average of $85 per hour.
Felicis finds breakout companies early and supports them through fast growth. They’re willing to lead huge rounds that many traditional investors won’t touch.
Investment Strategy: Felicis focuses on product-first companies with great founding teams. They invest from $500,000 (early stage) to $350 million+ (growth stage), making concentrated bets on companies they really believe in.
8. Khosla Ventures
Notable October Investments:
- General Intuition ($134M seed – co-led)
- Reflection AI ($2B Series B – co-investor)
- Multiple undisclosed AI investments
Total October AI Investments: $200M+ across 4+ deals
Khosla Ventures co-led General Intuition’s huge $134 million seed round. This AI startup works on spatial reasoning—helping AI understand the physical world. Founder Vinod Khosla loves “black swan” technologies that create entirely new markets.
Managing $15 billion, Khosla was an early investor in both OpenAI and Anthropic. That puts them at the center of the AI revolution. They invest from $500,000 to over $100 million.
Khosla’s portfolio includes over 50 AI companies that have raised $30+ billion total from all investors. Being backed by Khosla is a big deal—it shows other investors the company is serious.
Investment Philosophy: Technologies that can create massive new markets. Khosla especially likes AI infrastructure, foundational models, and AI applications that could transform entire industries.
Key Partners: Vinod Khosla stays actively involved. Partners Kanu Gulati (AI/ML specialist), Alex Morgan, and Nima Rahmany lead AI investments across the portfolio.
9. Index Ventures
Notable October Investments:
- Fireworks AI ($250M Series C – co-led)
- Multiple AI infrastructure investments
Total October AI Investments: $150M+ across 3+ deals
Index Ventures, based in London, co-led Fireworks AI’s $250 million round. This shows their commitment to AI infrastructure that helps companies use AI models in production.
Index brings a global view. They help U.S. companies expand to Europe and European startups grow in America. This bridge between markets is valuable for AI companies.
The firm has built a strong portfolio of AI companies across infrastructure, developer tools, and specialized applications.
Investment Focus: Infrastructure and developer tools from Series A through growth stage. They especially like companies building foundational technologies for deploying AI at scale.
10. Basis Set Ventures
Notable October Investments:
- Mem0 ($24M combined rounds – led Series A)
- Multiple AI infrastructure seed rounds
Total October AI Investments: $30M+ across 3+ deals
Basis Set Ventures led Mem0’s $24 million funding (combining two rounds). Mem0 builds persistent memory for AI agents—solving a big problem where AI can’t remember past conversations.
While smaller than mega-funds, Basis Set’s focused approach on AI infrastructure has worked well. They specialize in early-stage investments where technical knowledge and hands-on help create the most value.
Investment Strategy: Seed and Series A investments in technical infrastructure that enables next-generation AI applications. They focus on solving fundamental problems in AI development.
Emerging AI Investors to Watch (Active in October)
Disruptive
Joined Reflection AI’s $2 billion round. They bring growth equity expertise to frontier AI development. The firm focuses on tech companies with proven business models entering fast growth.
DST Global
Co-invested in Reflection AI’s huge round. This is Yuri Milner’s firm showing continued belief in foundational AI infrastructure. DST brings late-stage capital and help preparing for going public.
1789 Capital
This private equity firm (backed by Donald Trump Jr.) joined Reflection AI’s round. It signals political capital entering AI infrastructure. The firm focuses on American technology leadership.
B Capital Group
Co-invested in Reflection AI. Founded by Facebook/Meta co-founder Eduardo Saverin, they bring tech networks and operational expertise to frontier AI development.
ICONIQ
Joined Legora’s $150 million round. They bring family office and institutional capital to specialized AI applications. ICONIQ manages money for tech executives and ultra-wealthy individuals.
Evantic
Co-led Fireworks AI’s Series C. This shows emerging funds can compete in large AI infrastructure deals despite being newer players.
Peak XV Partners (formerly Sequoia India)
Joined Mem0’s funding and other AI rounds. They bring Asian market expertise and capital to global AI development.
Investment Trends: October 2025
1. Mega-Rounds Dominated
The top 3 deals (Reflection AI $2B, Poolside $500M-$1B, Mercor $350M) made up over 55% of total October AI funding. Money is concentrating around breakthrough companies.
2. Coding AI Explosion
Investors poured money into Poolside, Reflection AI, Reducto, and Fireworks AI. They believe AI-powered software development is worth trillions of dollars.
3. Legal AI Maturity
Harvey raised $150M at $8B value and Legora raised $150M at $1.8B value. This shows AI for professional services is reaching unicorn scale and beyond.
4. Infrastructure Over Applications
65% of October funding went to infrastructure companies (foundational models, inference platforms, coding tools) versus enterprise or consumer applications.
5. Corporate VCs Rising
Nvidia’s dominant role, plus investments from Micron Ventures, MediaTek Ventures, and others, show corporate strategic capital increasingly shapes AI development.
6. European AI Momentum
Legora’s $150M round is Sweden’s largest legal-tech funding ever. This signals European AI companies reaching global scale, though U.S. companies still dominate total funding.
7. Massive Seed Rounds
General Intuition’s $134M seed shows a new pattern: exceptional founding teams and breakthrough technology can get growth-stage money right from the start.
8. Follow-On Concentration
Many October investments were follow-on rounds for existing portfolio companies (Fireworks AI, Harvey, Poolside). VCs are doubling down on proven winners.
9. Open Source Push
Reflection AI’s $2B specifically for open-source frontier models shows market demand for alternatives to OpenAI and Anthropic’s closed approaches.
10. Valuation Acceleration
Multiple companies achieved 4x-15x value increases in under 12 months (Reflection AI, Mercor, Poolside). This shows compressed timelines for AI success.
October vs. September 2025: Key Differences
October Total Funding: ~$5-6 billion (compared to September’s $10+ billion)
October’s funding was lower than September’s record month. But the average deal size stayed high at $150+ million. The month had fewer mega-rounds but more consistent mid-sized investments.
Shift Toward Infrastructure: October showed 65% infrastructure focus versus September’s 48%. VCs are prioritizing foundational technologies over pure applications.
Coding AI Emergence: October had much more investment in AI coding platforms (Poolside, Reflection AI) compared to September’s focus on enterprise applications.
European Strength: Legora’s $150M round marked one of the largest European AI investments in 2025. This shows regional AI ecosystems growing beyond U.S. dominance.
Conclusion
October 2025 showed AI venture capital maturing. Investors selectively backed infrastructure, specialized applications, and frontier models with proven traction. While total funding dropped from September’s record highs, deal quality stayed excellent with multiple unicorn creations.
The month’s investments show clear themes: coding automation, legal AI, infrastructure, and open-source models attract the most capital. Corporate strategic investors, especially Nvidia, increasingly shape the ecosystem through massive investments.
As we enter the final months of 2025, AI investment shows no signs of slowing. The companies funded in October will likely define the next generation of artificial intelligence. They’re transforming industries from software development to professional services to enterprise infrastructure.