Marc Lowell Andreessen, born July 9, 1971, in Cedar Falls, Iowa, and raised in New Lisbon, Wisconsin, is a German-American entrepreneur, investor, and early internet pioneer. Son of Patricia Andreessen (customer service operator at Lands' End) and Lowell Andreessen (sales manager for Pioneer Hi-Bred International), he has a younger brother, Jeff. He discovered computer programming at age 12 and attended New Lisbon High School. Andreessen earned a Bachelor of Science in Computer Science from the University of Illinois at Urbana-Champaign in December 1993, with internships at IBM and as a programmer at the National Center for Supercomputing Applications (NCSA) earning $6.85/hour. His career highlights include co-authoring Mosaic, the first web browser with inline images, in 1993 with Eric Bina; co-founding Netscape Communications in 1994 with Jim Clark, serving as VP Technology and later CTO, before its $4.3 billion acquisition by AOL in 1999; co-founding Loudcloud (renamed Opsware in 2003), sold to Hewlett-Packard for $1.6 billion in 2007; co-founding Ning, sold for $150 million in 2011; and co-founding Andreessen Horowitz (a16z) in 2009 with Ben Horowitz, where he serves as General Partner managing funds including a $4.5 billion crypto fund (2022) and American Dynamism (2023). Selected board memberships include Meta Platforms (current), eBay (2008-2014), Hewlett Packard Enterprise (until 2018), and Skype (2009-2011, sold to Microsoft for $8.5 billion). Personal investments encompass Facebook, Twitter/X, GitHub, Pinterest, LinkedIn, and special economic zones like California Forever and Próspera. In his personal life, Andreessen married Laura Arrillaga (daughter of real estate billionaire John Arrillaga) in 2006; they have one son, John (born ~2015 via gestational surrogate). He resides in properties including a Malibu estate purchased for $177 million in 2021, after selling an Atherton, California mansion for $27 million in August 2025, and is active on X/Twitter as @pmarca. Politically, he supported Democratic candidates like Clinton, Gore, Kerry, Obama, and Hillary Clinton (2016), with a donation to Mitt Romney in 2012, but shifted in 2024 to advise Donald Trump, donate $3 million to MAGA Inc. PAC (2025), and back pro-crypto initiatives like Fairshake. A self-described techno-optimist, he published a manifesto in 2023 and has been involved in Signal/WhatsApp groups fostering Silicon Valley-US right alliances. His net worth is estimated at $1.9-2 billion as of 2025. Controversies include hypocrisy on housing policy (advocating supply increases but opposing multifamily zoning in Atherton, 2022), a 2016 Facebook lawsuit alleging conflict of interest in advising Mark Zuckerberg, leaked 2025 messages criticizing NSF's DEI policies and advocating a 'bureaucratic death penalty,' a deleted 2016 tweet on Indian net neutrality, and a 2014 public feud with Carl Icahn over eBay-PayPal. He is a prominent Silicon Valley investor and technologist.