Marc Andreessen

Marc Andreessen - Quick Facts

Profile Overview of Marc Andreessen

Marc Lowell Andreessen ( an-DREE-sən; born July 9, 1971) is an American businessman, venture capitalist, and former software engineer. He is the co-author of Mosaic, the first web browser to display inline images; co-founder of Netscape; and co-founder and general partner of Silicon Valley venture capital firm Andreessen Horowitz. He co-founded and later sold the software company Opsware to Hewlett-Packard; he also co-founded Ning, a company that provides a platform for social networking websites. In 2024, he became an advisor to Donald Trump. As of June 2026, Forbes estimated Andreessen's net worth at $1.9 billion.

This profile of Marc Andreessen covers Early Life and Family Background, Netscape, Opsware, Andreessen Horowitz and Business Ventures.

Early Life and Family Background of Marc Andreessen

Andreessen was born in Cedar Falls, Iowa, and raised in New Lisbon, Wisconsin, which he considered "the sticks". He is the son of Patricia, customer service operator at Lands' End, and Lowell Andreessen, who worked as a sales manager for the seed producer Pioneer Hi-Bred International. He has a younger brother named Jeff. Andreessen has stated that he had problematic relationships with his parents and brother, and that he did not like to talk about them.

Andreessen discovered programming at age 12. In December 1993, Andreessen received his bachelor's degree in computer science from the University of Illinois at Urbana–Champaign (UIUC). As an undergraduate, he interned twice at IBM in Austin, Texas. He worked in the AIX graphics software development group responsible for the MIT X implementation and ports of the 3D language APIs: SGI's Graphics Language (GL) and PHIGS. He also worked as a programmer, earning $6.85 per hour (equivalent of $15.49/hr in 2026), at the National Center for Supercomputing Applications (NCSA) at the University of Illinois. At that time, he became familiar with Tim Berners-Lee's open standards for the World Wide Web, but the World Wide Web browser required advanced programming skills to use.

After being shown the graphic web browser ViolaWWW in late 1992, Andreessen and full-time salaried co-worker Eric Bina worked on creating a browser with integrated graphics that could be ported to a wide range of computers, including Windows. The result was the Mosaic web browser released in 1993. The new web browser led to a 342,000 percent increase in web traffic in a year. Before Mosaic, there had only been 50 websites on the Web, but the number now increased to 10,000, while the percentage of internet users who surfed the Web increased from 1% to 25%.

Mosaic is often referred to as the first successful web browser. It was also the first browser widely used for both Windows and Mac.

The NCSA though refused to give the Mosaic team credit for their contribution, so Andreessen, disillusioned, decided to leave the center in 1994.

Netscape of Marc Andreessen

After graduating from the University of Illinois Urbana-Champaign in 1993, Andreessen moved to California to work at Enterprise Integration Technologies. Andreessen then met with Jim Clark, the founder of Silicon Graphics, who had recently exited the firm. Clark believed the Mosaic browser had great commercial possibilities and suggested starting an Internet software company. Soon, Mosaic Communications Corporation was in business in Mountain View, California, with Andreessen as co-founder and vice president of technology. The University of Illinois was unhappy with the company's use of the Mosaic name, so Mosaic Communications changed its name to Netscape Communications, and its flagship Web browser was named Netscape Navigator. Netscape was the first successful commercial web browser (offered for free). It offers a wide variety of clients, servers, development tools and e-commerce applications. It also simplified the interface, increased speed and provided tools to support financial transactions in comparison with its predecessor Mosaic.

Netscape's IPO in 1995 put Andreessen in the public eye. He was on the cover of Time and other publications.

Netscape was acquired in 1999 for $4.3 billion by AOL. Andreessen's hiring as its chief technical officer was contingent on the completion of the acquisition. The same year, he was named to the MIT Technology Review TR100 as one of the top 100 innovators in the world under the age of 35.

Opsware

After AOL acquired Netscape in late 1998, Andreessen founded Opsware with Ben Horowitz, Tim Howes, and In Sik Rhee. Originally named Loudcloud, the company provided computing, hosting and software services to consumer-facing internet and e-commerce companies. Loudcloud sold its hosting business to EDS and changed its name to Opsware in 2003, with Andreessen serving as chairman. Acquired by Hewlett-Packard for $1.6 billion in 2007, it was one of the first companies to offer software as a service and to attempt cloud hosting.

Andreessen Horowitz

Between 2005 and 2009, Andreessen and Horowitz separately invested $80 million in 45 startups, including Twitter and Qik. The two became well known as super angel investors. On July 6, 2009, Andreessen and Horowitz announced their Silicon Valley venture-capital firm Andreessen Horowitz.

Andreessen Horowitz began with an initial capitalization of $300 million; within three years the firm grew to $2.7 billion under management across three funds. In 2012, Andreessen Horowitz's portfolio holdings included Facebook, Foursquare, GitHub, Pinterest, Twitter and Honor Technology. In 2021, Business Insider notes that successful IPOs that have cemented Andreessen Horowitz's reputation include Okta, Inc., PagerDuty, Pinterest, Accolade, Slack Technologies, Lyft, DigitalOcean and Coinbase.

Both Andreessen and the firm have an interest in cryptocurrency. In 2021, the firm launched a $2.2 billion crypto-focused fund, which was followed by a 2022 $4.5 billion fund dedicated to crypto and blockchain. Notable crypto and NFT startups in its portfolio include Alchemy, Dapper Labs, Avalanche, OpenSea, Solana and Yuga Labs.

In 2023, the firm launched the American Dynamism fund, which focuses on hard tech sectors which serve national interest, including space, defense, manufacturing, robotics. The fund has backed companies like the defense manufacturing startup Hadrian and the hypersonic long-range rocket startup Castelion. In 2024, Andreessen Horowitz launched the 12-month American Dynamism Engineering Fellows Program, which was intended to recruit and train technologists. Also associated with the American Dynamism fund is the annual American Dynamism summit sponsored by Andreessen Horowitz, which gathers startup founders, investors, Members of Congress and Defense Department officials. The summit is officially non-partisan and has partnered with Democratic defense officials like former Deputy Secretary of Defense Kathleen Hicks.

On September 1, 2009, an investor group that included Andreessen Horowitz acquired a majority stake in Skype at a valuation of $2.75 billion, which was considered risky. The deal paid off in May 2011 when Microsoft bought Skype for $8.5 billion. In 2010, the firm assisted Silicon Valley attorney Ted Wang in creating the first free standardized seed round financing documents, the Series Seed Documents.

Source: adapted from Wikipedia (https://en.wikipedia.org/wiki/Marc_Andreessen), text available under CC BY-SA 4.0.