Marc Andreessen
Co-founder and general partner of Andreessen Horowitz
The Netscape co-founder and Andreessen Horowitz partner whose firm is one of the largest backers of AI startups.
Biography
Marc Andreessen is an American businessman, venture capitalist and former software engineer. He co-authored Mosaic, the first web browser to display inline images, co-founded Netscape, and co-founded and is general partner of the venture capital firm Andreessen Horowitz, launched in 2009 with Ben Horowitz. He also co-founded Opsware and Ning.
Andreessen Horowitz has invested heavily in AI, including Mistral AI in France and Black Forest Labs in Germany, and in July 2025 it led the largest seed round in history for Thinking Machines Lab, which raised a record $2 billion at a $12 billion valuation. Forbes featured him on its June 2024 cover with Reid Hoffman and Vinod Khosla in its issue on the epic battle for AI's future. He has said he opposes strict regulation of industries he invests in, including AI and cryptocurrency.
Notable contributions
Co-founded Andreessen Horowitz
Co-founded the venture capital firm Andreessen Horowitz with Ben Horowitz in 2009, which grew to $2.7 billion under management within three years.
Led a record $2 billion seed round in Thinking Machines Lab
In July 2025 Andreessen Horowitz led the largest seed round in history for the AI startup Thinking Machines Lab, valuing it at $12 billion.
Co-authored the Mosaic browser
Co-authored Mosaic, the first web browser to display inline images, and co-founded Netscape.