Andreessen Horowitz (also known as a16z) is an American privately-held venture capital firm headquartered in Menlo Park, California, United States. It was founded in 2009 by Marc Andreessen and Ben Horowitz. The number "16" in the name comes from the letter count between the first letter in Andreessen and the last letter in Horowitz.
Andreessen Horowitz invests in both early-stage startups and established growth companies. Its investments span the healthcare, consumer, cryptocurrency, gaming, fintech, education, and enterprise software (including cloud computing, security, and software as a service) industries.
As of January 2026, the company has $90 billion in assets under management.
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Founding and partnering
Between 2006 and 2010, Marc Andreessen and Ben Horowitz actively invested in technology companies. Both separately and together, they invested $4 million in 45 startups, including Twitter. During this time, the two became known as "super angel" investors.
On July 6, 2009, Andreessen and Horowitz launched their venture capital fund with an initial capitalization of $300 million. In November 2010, at a time when the field of venture capitalism was contracting, the company raised an additional $650 million for a second venture fund. In less than two years, the firm was managing a total of $1.2 billion under the two funds.
As of March 27, 2014, the firm was managing $4 billion in assets following the closing of its fourth fund at $1.5 billion.
In addition to Andreessen and Horowitz, the firm's general partners include Jeff Jordan, Chris Dixon, Martin Casado, and Andrew Chen. Ex-VMware CEO Raghu Raghuram joined the firm as general partner in October 2025. Margit Wennmachers served as operating partner from 2010 to July 2025, when she became partner emeritus.
In March 2019, it was reported that Andreessen Horowitz was opening an office in San Francisco.
In January 2022, Andreessen Horowitz raised $9 billion for its venture capital, growth-stage, and biotech-focused funds.
In January 2026, Andreessen Horowitz raised $15 billion across five new funds.
As of March 2026, the firm is managing at least $90 billion in assets.
Investments
By 2012, Business Insider wrote that, "Andreessen Horowitz is the most powerful and respected venture capital firm in Silicon Valley right now." The firm is often cited as the largest and one of the most powerful venture capital funds in the world. Marc Andreessen in particular is often cited as one of the most powerful venture capitalists, who is dominant, if also controversial, not only in Silicon Valley, but also in politics.
As per the website OfficeChai's calculations (up to October 2025), since 2020, Andreessen Horowitz has backed 32 unicorns, more than any other venture firm. By November 2025, Andreessen Horowitz's website lists 1076 portfolio companies. The note reads: "Any investments or portfolio companies mentioned, referred to, or described on this page are not representative of all investments in vehicles managed by a16z and there can be no assurance that the investments will be profitable or that other investments made in the future will have similar characteristics or results. Exits include current and former a16z portfolio companies which have been acquired as well as companies which have undergone an initial public offering or direct public offering of shares. Certain publicly traded companies on this list may still be held in Andreessen Horowitz funds." The American Dynamism section lists 50 companies.
Leslie Feinzaig writes on Fast Company that nowadays Andreessen Horowitz and other big firms do not act like traditional venture capital firms anymore, but invest beyond early-stage private companies, including public equities, crypto tokens, non-traditional assets, and more. There is also a tendency towards competing for the obvious alpha, and not just making the contrarian's bet.
Andreessen Horowitz presents their primary political agenda as defending Little Tech (startups), in contrast to Big Tech incumbents. In April 2025, together with Y Combinator and AI companies like Anyscale, Exowatt, and Sourcegraph, the firm launched American Innovators Network, a coalition that represents "America's Little Tech ecosystem leading the next era of innovation and economic growth".
John Mac Ghlionn of the Boston Globe refers to "Small Tech" and defines it as "a cluster of small Silicon Valley firms" that represents the "AI-driven military-industrial complex" with Palantir as "its public face", writing that, "The deeper roster runs through Anduril, Shield AI, Saronic, Scale AI, Vannevar Labs, Skydio, Epirus, and a dozen more startups bankrolled by the venture capital firm Founders Fund, Andreessen Horowitz, and Peter Thiel's wider network."
American Dynamism
In 2023, the firm launched a $600 million American Dynamism fund "with the broad aim of supporting companies building in the nation's interest". American Dynamism has raised two funds since its establishment, with a total value of $1.8 billion. The fund focuses on hard tech sectors which serve national interest, including space, defense, manufacturing, robotics. 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.
The fund has been managed by three general partners, namely Katherine Boyle, David Ulevitch and Erin Price-Wright. In July 2026, Connor Love was added to the team. David Ulevitch is the leader.
Boyle plays an important role in the initiative. She declares in an essay titled "Building American Dynamism" that, "I believe the only way to reverse the course of stagnation and kick-start nationwide renewal post-Covid is through technologists building companies that support the national interest." She had previously interned at Founders Fund and is influenced by Peter Thiel's thinking. In 2016, she joined General Catalyst where she helped fund Anduril, before joining Andreessen Horowitz. Her portfolio at Andreessen Horowitz includes Hadrian, Apex Space (satellites) and Castelion (hypersonic weapons).
Other notable companies supported by American Dynamism include:
Applied Intuition: After its 2025 Series F ($600 million), its valuation reached $15 billion. Originally, its AI software focused on helping automobile companies like Toyota and Porsche in the development of their autonomous driving technology. Later the startup's defense division has increasingly applied this technology the US military, covering areas like "map aerial, maritime and land environments", also working to "simulate new ones, and use the data to improve unmanned systems". The software is also used "to coordinate attacks using autonomous drones from multiple vendors". The company is expanding into space.
Notable portfolio companies (outside American Dynamism)
Advanced Manufacturing Company of America (Amca): aerospace and defense company, that acts as a layer between startups and legacy players. It acquires old defense companies that make power units, sensors and flight-control computers to rebuild the supply chain for companies like Boeing and Airbus. The company launched in April 2025 with $76.5 million in initial funding. Backers include Founders Fund, Caffeinated Capital, Lux Capital, Andreessen Horowitz. Andreessen Horowitz continued to join the $300M Series B in April 2026.
Databricks: In 2013, Reuters reports that Andreessen Horowitz "quietly invested $14 million in a mysterious new venture called Databricks". It is a Silicon Valley Defense Group company, alongside others like Anduril, Scale AI and Shield AI.
Mistral AI: Andreessen Horowitz is one of the company's main backers. The company works with the French Ministry of Defense and is expanding its service towards Ukraine.
Starcloud: startup that develops space-based data centers. Andreessen Horowitz has backed it since the seed round in 2024.
Asana: Andreessen Horowitz has supported the company since its Series A (2009).
Cluely: AI assistant startup which is backed Andreessen Horowitz, which led a $15 million Series A for the company in 2025.
Cursor (former Anysphere): According to Forbes, Andreessen Horowitz owns a 10% stake ($6 billion). In June 2026, SpaceX acquired Cursor, paying $60 billion entirely in SpaceX's Class A shares.
Deel, Inc.: AI-based human resources startup. Andreessen Horowitz is its long-time backer and the fund's Anish Acharya sits on the company's board.
ElevenLabs: AI company that works on synthetic voices. Andreessen Horowitz co-led its Series A (2023), B (2024), C (2025) and participated in the $500 million Series D (2026).
Investments by timeline
In 2009, Andreessen Horowitz made its first two investments: one in business management SaaS developer Apptio and one in Skype stock.
According to Horowitz, the Skype investment was seen as risky by other experts in the field, who believed the company would be crippled by ongoing intellectual property litigation and direct competitive attacks from Google and Apple. The firm's founders viewed the investment as a success following Skype's sale to Microsoft in May 2011 for $8.5 billion.
In 2010, Andreessen Horowitz invested $10 million in the cloud company Okta, leading its Series A round.
In 2011, Andreessen Horowitz invested $80 million in Twitter, becoming the first venture firm to hold stock in all four of the highest-valued privately held social media companies at the time: Facebook, Groupon, Twitter, and Zynga.
Andreessen Horowitz also invested in Airbnb, Lytro, Jawbone, Belly, Foursquare, Stripe, and other high-tech companies.
In 2012, Andreessen Horowitz invested in 156 companies, including 90 in its portfolio and 66 startups through its funding of Y Combinator's Start Fund. The company invested $100 million in GitHub, which netted over $1 billion for the fund when Microsoft acquired GitHub for $7.5 billion. In 2013, Andreessen Horowitz invested in Clinkle, Coinbase, Databricks, Lyft, Oculus VR, PagerDuty, Pixlee, Ripple, Soylent, Swiftype, and uBiome.
In 2014, the firm led a $57 million Series B round in the A/B testing startup Optimizely. The same year, the company invested in several more companies, including Tanium for $90 million, BuzzFeed, and Forward Networks. In 2015, the firm invested $40 million in Stack Exchange, $2.8 million in Distelli, and $80 million in cloud-based CAD software company Onshape. Also in 2015, Andreessen Horowitz invested in the blogging platform Medium, Samsara, Improbable, Honor, Inc., OpenBazaar, a blockchain startup, and nootropics and biohacking company Nootrobox.
In 2016, the firm led an $8.1 million Series A round in Everlaw, a legal technology company, and led a $3.5 million Series Seed round in RapidAPI, an API connection platform for developers. Also in 2016, the firm invested $2 million in Cardiogram, a digital health company, and in Apeel Sciences, a food science business.
Structure
Andreessen Horowitz partners work on behalf of all its portfolio companies, an approach modeled after the Hollywood talent agency Creative Artists Agency. In 2010, the company hired Margit Wennmachers, a marketing executive at the partner level.
As of 2011, the firm had maintained a database of designers, coders, and executives and used it to help fill positions at its startups. Former U.S. Treasury Secretary Larry Summers became a special advisor to Andreessen Horowitz in June 2011.
In 2012, former Washington D.C. mayor Adrian Fenty was appointed Andreessen Horowitz's second special advisor. Fenty was hired to advise the firm's portfolio companies on working with local, state, and federal governments.
In 2019, the firm applied to restructure as a registered investment adviser in order to have more freedom to take on riskier bets like cryptocurrency.
Politics
In May 2026, Andreessen Horowitz was reported to be the largest spender in that year's US elections.