Andreessen Horowitz
About Andreessen Horowitz
Andreessen Horowitz, also called a16z, was founded in 2009 by Marc Andreessen and Ben Horowitz and is based in Menlo Park, California. Wikipedia lists more than $100 billion in assets under management as of 2026 and more than 500 employees as of 2024. The firm announced in 2025 that it had raised $15 billion. Shangda Xu and David George lead the firm's investments across the AI infrastructure stack.
The firm backs technical founders building across AI infrastructure, defense and other areas. Its newest vehicle, the Machine Age Fund, closed at $1.1 billion for hardware, with a focus on AI processors, memory chips, networking and robotics. Recent AI rounds on the Lounge deals desk include Anduril's Series H of $5 billion in May 2026, Cognition's Series E of $2 billion in September 2026, and Mistral AI's Series D of $3.58 billion in September 2026. Earlier, a16z led Character.AI's $150 million Series A in 2023 and joined OpenAI's $300 million Series B the same year.
The firm's LinkedIn profile says it is stage agnostic and invests from seed through late stage. The firm has not published check sizes. Third-party trackers give different estimates: one lists check sizes from $1 million to $200 million, and another estimates seed rounds of $1.7 million to $20 million and Series A rounds of $9 million to $55 million. These figures are estimates, not firm disclosures.
- Anduril Industries: Series H, $5B, May 2026, led by a16z
- Cognition: Series E, $2B, September 2026, led by a16z; a second backing by the firm
- Mistral AI: Series D, $3.58B, September 2026; earlier Series C, $2B, September 2025
- Harvey: Series H, $550M, September 2026
- EliseAI: Growth round, $350M, September 2026, led by a16z
- Castelion: Series C, $800M, August 2026, led by a16z
- Atoms: Growth round, $1.7B, July 2026, led by a16z
- OpenAI: Growth round, $122B, February 2026
- xAI: Series C, $6B, December 2024
- Safe Superintelligence: Series A, $1B, September 2024
- Character.AI: Series A, $150M, 2023, led by a16z
- linkedin.com/company/a16z
- en.wikipedia.org/wiki/Andreessen_Horowitz
- tradersunion.com/news/cryptocurrency-news/show/1245455-a16z-secures-15
- a16z.com/the-machine-age-fund
- finance.biggo.com/news/c5a6c068-c8d0-40e3-862c-015512809003
- aifunding.me/insights/a16z-ai-portfolio-analysis
- f4.fund/firms/a16z
- shizune.co/investors/profile/andreessen-horowitz
Investing activity
Andreessen Horowitz appears in 63 AI deals tracked by the AI Lounge deals desk, rounds totalling $152B, and led 39 of them. The rounds are mostly Seed, Series B and Growth, with a median round size of $53M and the largest at $122B. The most recent are Wabi (Venture round, $55M, Oct 2026), Dream (Seed, $17M, Oct 2026) and Town (Series B, $108M, Oct 2026).
Andreessen Horowitz most often invests alongside SV Angel, Lightspeed Venture Partners, Sequoia Capital and Nvidia, and the companies it backs on AI Lounge are mostly in AI, Foundation models and Personal AI assistant.
Deals
Frequently asked questions about Andreessen Horowitz
Who founded Andreessen Horowitz and when?
Andreessen Horowitz was founded in 2009 by Marc Andreessen and Ben Horowitz. The firm is headquartered in Menlo Park, California.
How much capital has Andreessen Horowitz raised for AI investing?
The firm announced it raised $15 billion in 2025, a total that covers AI and other technology bets. Its Machine Age Fund, focused on AI hardware, closed at $1.1 billion.
Which stages does a16z invest in?
The firm describes itself as stage agnostic and says it invests from seed to late stage. It has not published a check size range.
What is a typical check size at Andreessen Horowitz?
The firm has not made check sizes public. Third-party trackers estimate seed checks of about $1.7 million to $20 million and Series A checks of about $9 million to $55 million.
Which AI companies has a16z backed?
Recent examples on the Lounge deals desk include Anduril, Cognition, Harvey and Mistral AI. Earlier AI backings include OpenAI and Character.AI.
What AI companies has Andreessen Horowitz invested in?
Andreessen Horowitz's AI investments include Wabi, Dream, Town, TypeSafe AI, Arena, Vesta, Preference Model and Stuut. The 63 rounds on AI Lounge are listed on this page with amounts, dates and co-investors.
Where is Andreessen Horowitz based?
Andreessen Horowitz is based in Menlo Park, US.
What stage does Andreessen Horowitz invest at?
In the rounds tracked on AI Lounge, Andreessen Horowitz has invested at Seed, Series B, Growth and Series A, with a median round of $53M. Andreessen Horowitz led 39 of those rounds.
Who does Andreessen Horowitz co-invest with?
Andreessen Horowitz's most frequent co-investors on AI Lounge are SV Angel (8 deals), Lightspeed Venture Partners (8 deals), Sequoia Capital (7 deals), Nvidia (7 deals) and Accel (5 deals).
How can founders reach Andreessen Horowitz?
Founders on AI Lounge can see Andreessen Horowitz's contact details in AI Investor Contacts (paid plans), check for a warm introduction through members who worked with the firm under Warm Paths, and add Andreessen Horowitz to their Investor Pipeline to track the conversation.