Brian Nichols is the co-founder of Angel Squad, a community where you’ll learn how to angel invest and get a chance to invest as little as $1k into Hustle Fund's top performing early-stage startups

Andrew Chen graduated from the University of Washington with a degree in mathematics and began his career in growth. Before joining a16z he had built a blog at andrewchen.com with 650-plus essays on user growth, viral loops, churn curves, and network effects that became required reading across Silicon Valley's growth and product communities. Marc Andreessen and Ben Horowitz were among his readers before they became his employers.

He led Rider Growth teams at Uber during the company's most aggressive expansion period, applying the frameworks he had written about theoretically to one of the fastest-scaling consumer products of the 2010s. Uber's driver and rider acquisition machines during those years reflected his approach directly.

The Network Effects Thesis

Andrew Chen investments at a16z are grounded in a specific theory of value creation: the best consumer products have network effects, meaning they become more valuable as more people use them. That makes them winner-take-most markets. The challenge is getting from zero to the point where the network effect activates, which is what he calls the cold start problem.

His 2021 book of the same name, published by Harper Business, is an analysis of how products including Slack, Clubhouse, Zoom, Twitch, Tinder, Reddit, Uber, Airbnb, PayPal, and Dropbox survived that early period when the network was too small to be useful. Each chapter is a case study in a different cold start strategy. The book has sold hundreds of thousands of copies and is the reference text most often cited by marketplace and social product founders.

Portfolio companies at a16z that reflect this thesis include Clubhouse, the audio social platform that had one of the fastest cold-start periods in social media history, reaching 10 million users in months; Substack, the newsletter platform with clear network effects between writers and their subscriber bases; Snackpass, the social food ordering app; Sleeper, the fantasy sports platform with social features; Sandbox VR, the location-based virtual reality company; and Hipcamp, the outdoor hospitality marketplace.

Elizabeth Yin of Hustle Fund has noted that the investors who generate the best returns over time are those who develop a genuine theoretical framework for what they're looking for, then apply it consistently. Chen's Cold Start framework is exactly that: a testable, repeatable lens for evaluating whether a consumer startup has a viable path to network-effect dominance. Angel Squad members applying similar rigor to early-stage evaluation can access frameworks and deal flow alongside Hustle Fund GPs at hustlefund.vc/squad.

The Angel Portfolio Before a16z

Before joining a16z, Chen was an active angel investor across a portfolio that included AngelList, Dropbox, Gusto, Barkbox, Front, Product Hunt, and Tinder. He was also an advisor to early Atelier Ventures alongside Li Jin, reflecting his deep connection to the creator economy thesis. His pre-a16z investing showed the same pattern he later applied at the firm: consumer products with inherent network properties, backed by technical founders with strong product intuition.

His connection to the a16z team predated the hiring. Marc Andreessen and Ben Horowitz have publicly described Chen as the growth blogger whose writing helped shape their thinking about distribution and user acquisition. They invested in his first startup before he joined as a partner, and the company did not find product-market fit. That experience is something Chen has referenced as formative: understanding why products fail is as important as understanding why they succeed.

a16z Speedrun

In 2023, Andrew Chen launched a16z Speedrun, an accelerator program within a16z initially focused on gaming startups. The program invests up to $1 million per startup plus $5 million in credits from AWS, Google Cloud, OpenAI, Microsoft, NVIDIA, Stripe, and Deel. By 2025, Speedrun had expanded beyond gaming to cover all tech, entertainment, and AI startups, running cohorts of roughly 60 companies each cycle.

The name references speedrunning, the gaming practice of finishing a game as quickly as possible. The metaphor is deliberate: Speedrun is designed for founders who want to move fast from zero to fundable in a compressed timeline, with the a16z network behind them.

The accelerator model is itself an expression of Chen's network effects thesis. The value of going through Speedrun increases with the quality and density of the Speedrun alumni network. That network compounds.

The Writing as Infrastructure

Chen has written over 650 essays on his blog and Substack newsletter. Topics range from technical growth mechanics like viral coefficient calculations and churn curve analysis to broader frameworks on how products die and why. He was publishing daily before most VCs had Twitter accounts.

Shiyan Koh of Hustle Fund has emphasized that the investors who attract the best deal flow are those who put their frameworks into the world publicly. Chen is the clearest example of that in venture. His deal flow comes from founders who have been reading him for a decade before they launched their companies.