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September 12, 2026Short & citedBlog
Civic Viewpoint.
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How It Works • Venture Capital

Marc Andreessen

Marc Andreessen is an American businessman, venture capitalist, and former software engineer best known for co-authoring the Mosaic web browser, co-founding Netscape, and co-founding the venture capital firm Andreessen Horowitz.

Updated September 12, 20261 min readCited sources

Marc Andreessen is an American businessman, venture capitalist, and former software engineer best known for co-authoring the Mosaic web browser, co-founding Netscape, and co-founding the venture capital firm Andreessen Horowitz.

What it is

Marc Andreessen helped create Mosaic, an early graphical web browser that made the World Wide Web easier to use. He later co-founded Netscape Communications, which commercialized web browsing and became a major early internet company. He is also a co-founder and general partner of Andreessen Horowitz (a16z), a leading Silicon Valley venture capital firm.

Key details

Born July 9, 1971, in Cedar Falls, Iowa, Andreessen studied at the University of Illinois Urbana-Champaign. After Netscape, he co-founded Opsware and Ning. Forbes estimated his net worth at US$1.9 billion in June 2026. In 2024, he became an advisor to Donald Trump.

Why it matters

Andreessen's work on Mosaic and Netscape helped popularize the internet, shaping how people access information today. His venture capital firm, Andreessen Horowitz, has invested in many technology companies with global reach, making him relevant to Canadian readers through the broader North American tech ecosystem.

In short

  • Co-authored Mosaic, the first widely used graphical web browser.
  • Co-founded Netscape, a pioneering internet company.
  • Co-founded Andreessen Horowitz, a top venture capital firm.
  • Net worth estimated at US$1.9 billion (Forbes, June 2026).
Canadian angle

Andreessen Horowitz has invested in many technology companies with global reach, so Marc Andreessen is relevant to Canadian readers through the broader North American tech and venture capital ecosystem.

Quick questions

Who is Marc Andreessen?
Marc Andreessen is an American businessman, venture capitalist, and former software engineer best known for co-authoring Mosaic, co-founding Netscape, and co-founding Andreessen Horowitz.
What did Marc Andreessen invent?
He is best known for co-authoring Mosaic, an early graphical web browser that helped make the internet easier to use.
What is Marc Andreessen's net worth?
Forbes estimated Marc Andreessen’s net worth at US$1.9 billion in June 2026.

Sources

  1. Wikipedia — https://en.wikipedia.org/wiki/Marc_Andreessen
    Supports: Birth date, roles, Mosaic, Netscape, Andreessen Horowitz, net worth estimate, later career, 2024 advisory role
  2. Britannica — https://www.britannica.com/biography/Marc-Andreessen
    Supports: Birth date, birthplace, role in Mosaic, co-founding Netscape
  3. Andreessen Horowitz — https://a16z.com/author/marc-andreessen/
    Supports: Co-founder and general partner status, Mosaic, Netscape, Opsware background
  4. Stanford Technology Ventures Program — https://stvp.stanford.edu/people/marc-andreessen
    Supports: Mosaic development, Netscape co-founding, later leadership and investing roles
  5. Internet Hall of Fame — https://www.internethalloffame.org/inductee/marc-andreessen/
    Supports: Mosaic authorship and importance in early web browsing
  6. Wired — https://www.wired.com/2012/04/ff-andreessen/
    Supports: Mosaic as first graphical browser, Netscape significance