Andreessen Horowitz

About

Andreessen Horowitz (commonly known as a16z) is an American venture capital firm founded on July 6, 2009, by Marc Andreessen and Ben Horowitz, headquartered in Menlo Park, California ¹². Andreessen co-created Mosaic, the first widely used web browser, and co-founded Netscape; Horowitz served as CEO of Opsware (formerly Loudcloud), which sold to HP for $1.6 billion in 2007 ¹. Between 2006 and 2010, the pair personally invested $4 million in 45 startups, including Twitter, before formalizing their partnership ¹.

The firm launched with an initial fund of $300 million in 2009 ¹³. It raised a second fund of $650 million in November 2010, bringing total assets to $1.2 billion within two years ¹³. By March 2014, the firm managed $4 billion following the close of its fourth fund at $1.5 billion ¹. In January 2022, a16z raised $9 billion across venture, growth, and biotech funds ¹. In April 2024, the firm raised $7.2 billion across five funds: American Dynamism ($600M), Apps ($1B), Games ($600M), Infrastructure ($1.25B), and Growth ($3.75B) ⁴⁵. In January 2026, a16z raised $15 billion across five new funds: American Dynamism ($1.176B), Apps ($1.7B), Bio + Health ($700M), Infrastructure ($1.7B), and Growth ($6.75B) ⁶⁷. As of July 2025, a16z ranks first among venture capital firms by assets under management, with $46 billion ¹. The firm reports managing over $90 billion across all funds ².

In April 2019, a16z registered as a Registered Investment Adviser (RIA) with the SEC, formally ceasing to operate as a traditional venture capital firm ⁸. This allowed the firm to invest more than 20% of fund capital in liquid securities, particularly cryptocurrencies ⁸.

a16z pioneered the “platform model” in venture capital, assembling what it describes as the largest team of operators in venture, offering support in marketing, talent acquisition, legal, and policy ². The firm has over 150 people dedicated to supporting portfolio companies ⁹. As of 2026, a16z has invested in over 1,076 portfolio companies with a combined valuation exceeding $600 billion, including 121 unicorns and 35+ public offerings ¹⁰.

The firm maintains offices in Menlo Park (headquarters at Sand Hill Road), San Francisco, New York, and London ¹¹¹².

Stated Thesis

Andreessen Horowitz was built on the conviction that “software would eat the world, and the biggest tech companies would become far more valuable than anyone believed” ². Marc Andreessen articulated this thesis in his landmark 2011 Wall Street Journal essay, arguing that “in many industries, new software ideas will result in the rise of new Silicon Valley-style start-ups that invade existing industries with impunity” ¹³.

The firm publicly states it invests “in seed to venture to growth-stage technology companies, across AI, bio + healthcare, consumer, crypto, enterprise, fintech, games, infrastructure, and companies building toward American dynamism” ².

a16z articulates seven core cultural principles on its website ²:

1. “We do only first class business and only in a first class way” — emphasizing respect for entrepreneurs and timely communication.
2. Long-term relationships — “Our word is our bond.”
3. Future belief — Betting strategically on technological progress.
4. Diversity through merit — “We don’t have quotas… we have a goal to be the most talented firm.”
5. Celebration — Recognizing individual and collective achievements.
6. Competitive excellence — “We play to win” by investing in the best companies rather than seeking bargains.
7. Team focus — “Every time we win, we win as a team.”

The firm states it will “never publicly criticize any entrepreneur or startup,” calling this a “fireable offense” ². Ben Horowitz has stated that a16z prioritizes company success over founder retention, and that “a great investor with the right help, the right networking, and the right expertise at the right time can be the difference between success and failure” ⁵.

Marc Andreessen has described the firm’s founder evaluation: “The decision should be around people… about 90% of the decision is people” ¹⁴. He also states: “We are looking for a magic combination of courage and genius… Courage is the one people can learn” ¹⁴.

In January 2026, Ben Horowitz framed the firm’s $15 billion raise around ensuring American technological leadership, arguing it is “fundamentally important for humanity that America wins” the technology competition and identifying AI and crypto as “key architectures” for the next era ⁶.

Inferred Thesis

The following analysis is based on publicly verified portfolio data and a16z’s own investment list. According to Tracxn, a16z has made 1,157 investments over 17 years ¹⁵. The firm’s portfolio page lists 1,076+ companies ¹⁰. GrowthList categorizes the portfolio as follows ¹⁰:

Sector Allocation (based on GrowthList categorization of 1,076+ portfolio companies)

• AI / Machine Learning: 440+ companies (approximately 40%) ¹⁰
• B2B SaaS / Enterprise Software: 300+ companies (approximately 28%) ¹⁰
• Healthcare & Biotech: 200+ companies (approximately 19%) ¹⁰
• Consumer & Entertainment: 200+ companies (approximately 19%) ¹⁰
• Fintech / Financial Services: 150+ companies (approximately 14%) ¹⁰
• American Dynamism (defense, aerospace, manufacturing): 50+ companies (approximately 5%) ¹⁰

Note: Categories overlap as many companies span multiple sectors (e.g., an AI healthcare company counts in both AI and healthcare). Percentages do not sum to 100% due to this overlap.

Stage Distribution (from Tracxn data on 1,157 investments)

• Seed: 469 investments (41%) with average round size of $17.6M ¹⁵
• Series A: 368 investments (32%) with average round size of $24.1M ¹⁵
• Series B: 131 investments (11%) with average round size of $118M ¹⁵
• Later stages: the remainder (~16%)

Despite investing across all stages, a16z’s largest fund allocation is consistently to growth — the 2024 Growth fund was $3.75 billion (52% of the $7.2B raise) ⁴, and the 2026 Growth fund was $6.75 billion (45% of the $15B raise) ⁶. This indicates a firm that increasingly deploys the majority of its capital at later stages while maintaining seed and Series A presence for deal flow and early access.

Geographic Concentration

The portfolio is 78% US-based, 2% UK-based, and 20% distributed globally ¹⁰. The firm’s headquarters are in Menlo Park with offices in San Francisco, New York, and London ¹¹¹².

Check Size

Based on available data ¹⁰: - Speedrun Accelerator: $750K–$1M - Seed: $1M–$5M - Series A: average $24.1M ¹⁵ - Series B: average $118M ¹⁵ - Growth / Late Stage: $50M–$500M+ - Special situations: $1B+ (e.g., OpenAI, xAI) ¹⁰

Co-Investor Patterns

Based on the 20 startup profiles in this database, a16z is the most frequently appearing co-investor across our profiled companies, appearing alongside investments from SV Angel, Sequoia Capital, Kleiner Perkins, Founders Fund, and other top-tier firms. a16z frequently co-invests with Sequoia at growth stages (both appear in Airbnb, Stripe, Databricks, OpenAI) and with SV Angel at seed stages.

Notable Gaps Between Stated and Actual Thesis

• AI concentration has accelerated dramatically. While a16z lists nine equal focus areas on its website, approximately 40% of portfolio companies involve AI/ML, making it the firm’s dominant sector by far. The 2025 funding mix for AI-focused investments was reportedly 40% healthcare, 25% infrastructure, 20% vertical copilots, 15% entertainment/logistics ¹⁰.
• Crypto commitment despite losses. The flagship Crypto Fund I lost approximately 40% in the first half of 2022 ¹⁶, yet the firm continued raising large crypto-dedicated funds ($4.5B Crypto Fund 4 in 2022 ¹⁷, seeking $2B for Crypto Fund 5 in 2026 ¹⁸). This represents genuine conviction rather than performance-chasing.
• “American Dynamism” is a differentiator. The dedicated defense/aerospace/manufacturing fund ($600M in 2024, $1.176B in 2026) distinguishes a16z from peers who avoid these sectors. Portfolio companies like Anduril, Shield AI, Hadrian, and Flock Safety represent meaningful deployment in hardware-intensive, government-adjacent businesses ⁴⁶.
• Growth dominance vs. seed origins. While the firm is famous for early investments (Instagram, Airbnb, Coinbase), the majority of capital is now deployed at growth stage. The 2026 Growth fund alone ($6.75B) exceeds the entire firm’s AUM from its first five years.
• The platform model is the thesis. Unlike firms that compete purely on brand or check size, a16z’s 150+ person operating team is a structural differentiator ⁹. This “we are a machine you can quickly plug into” approach (Ben Horowitz’s framing) means the firm competes on services, not just capital.

Portfolio

The following table includes a16z investments verified through the firm’s own portfolio page, Crunchbase, press coverage, and our existing startup profiles. a16z has 1,076+ portfolio companies ¹⁰; this table represents approximately 9% of the full portfolio, focused on the most notable investments.

Note: This table includes 71 companies out of 1,076+ total portfolio companies (~7%). Investment years are approximate where exact dates are not publicly confirmed. Many investments span multiple rounds; the stage listed reflects a16z’s initial or most significant investment.

In Their Own Words

Marc Andreessen on technology and investing:

“Most of the big breakthrough technologies/companies seem crazy at first: PCs, the internet, Bitcoin, Airbnb, Uber, 140 characters.” ¹⁴

“The decision should be around people… about 90% of the decision is people.” ¹⁴

“We are looking for a magic combination of courage and genius… Courage is the one people can learn.” ¹⁴

“About 15 of those will generate 95% of all the economic returns… even the top VCs write off half their deals.” ¹⁴

“We invest in these companies with a ten-year outlook.” ¹⁴

Marc Andreessen on “Software Eating the World” (Wall Street Journal, 2011):

“In many industries, new software ideas will result in the rise of new Silicon Valley-style start-ups that invade existing industries with impunity.” ¹³

Ben Horowitz on founding a16z:

“A great investor with the right help, the right networking, and the right expertise at the right time can be the difference between success and failure.” ⁵

Ben Horowitz on American technological leadership (January 2026):

“Give them a shot at a great life regardless of their circumstance, background, ethnicity, religion, gender or any other attribute.” ⁶

Ben Horowitz on the $15B raise:

a16z bears responsibility as “the American leader in Venture Capital” to ensure America wins “the next 100 years of technology.” ⁶

Ben Horowitz on specialized funds:

“Founders building AI foundation models need an entirely different set of networks and capabilities than founders building biotech therapies.” ⁵

a16z on entrepreneur relations:

“We never publicly criticize any entrepreneur or startup (doing so is a fireable offense).” ²

a16z on investment strategy:

“Our strategy is to invest in the best companies, not get the best bargains.” ²

What Founders Say

Ali Ghodsi, CEO of Databricks:

“I don’t think Databricks would be around today if it wasn’t for a16z. And Ben specifically.” (Source: Not Boring by Packy McCormick) ³

“They truly believed in us.” ³

“They envision the full potential of the thing. When you’re knee deep in it… it’s hard to think about the world that way. But then they come to the board meetings and they tell you, ‘You’re going to take over the world.’” ³

“First and foremost, they just really care about the mission of the company. I don’t think Ben and Marc think of it as an investment return first. That comes second.” ³

Brian Chesky, Co-Founder and CEO of Airbnb:

“From the first time we met, Jeff struck me as somebody I should learn from.” (On Jeff Jordan joining Airbnb’s board; Source: Fortune) ²¹

Ben Silbermann, Co-Founder and CEO of Pinterest:

“[Jordan] saw similarities between Pinterest and the early days of eBay, which had aspects of commerce as well as aspects of community.” (On Jeff Jordan’s investment thesis; Source: Fortune) ²¹

Jeff Jordan (a16z General Partner) on first hearing Brian Chesky pitch:

“I went from complete cynic to complete believer in 30 minutes.” (Source: Fortune) ²¹

Note: The Ghodsi quotes are from an independently reported profile (Not Boring by Packy McCormick). The Chesky and Silbermann quotes are from independent Fortune reporting. The Jordan quote is included for context but is an investor quote, not a founder quote. No independently sourced negative or critical founder testimonials were found in this research pass. a16z’s own website does not feature a dedicated testimonials section.

Sources