Visualize where the first batch of founders from the famous startup accelerator Y Combinator are now.

In March 2005, Y Combinator cofounder Paul Graham announced the program that would become Y Combinator on his website.

Y Combinator also recently increased its number of cohorts or “batches” per year from two to four. Its leaders cited artificial intelligence’s rise as a reason for the increase.

Stanford’s archive of lectures about creating a startup includes advice from Y Combinator notables such as former YC president and OpenAI CEO Sam Altman and YC Cofounder Paul Graham.

Many of the philosophies that the leaders of Y Combinator have infused into the program’s portfolio companies have become the playbook for building the next big thing, such as its focus on founder personality and more.

In one of Paul Graham’s essays on his website, he took the time to explain how and why he and his cofounders (including his girlfriend at the time, and now wife, Jessica Livingston), came up with the idea of and eventually created Y Combinator.

The startup accelerator has funded more than 5,000 companies over the years. This YC-specific search engine lets you look up any company to find out if it's a YC alum.

That's according to a new study from Wharton. Y-Combinator, perhaps the most famous startup accelerator, currently has 16 alumni companies trading on the public market. But not every entrepreneur who joins a startup accelerator makes it big.

Led by CEO Sam Altman, OpenAI's mission is to "ensure artificial general intelligence benefits all of humanity" by making its products open to all users. In 2023, the $86B company behind the chatbot ChatGPT consisted of a for-profit arm under its nonprofit governing board.

Before becoming the head of OpenAI, Sam Altman was the president of Y Combinator—a startup accelerator company that supported companies like Airbnb, DoorDash, and Coinbase. In 2016, Altman interviewed Zuckerberg about creating Facebook and its growth over time. Zuckerberg said that, unlike other companies (think: CourseMatch), Facebook kept growing and adding new features, which prevented the app from becoming obsolete.

Y Combinator Cofounder Paul Graham’s former professor’s husband Julian Weber provided $10K in seed funding to Graham’s previous startup, Viaweb in its early days. In exchange, Weber received 10% of the company. Weber’s involvement inspired Graham to start a program where investors were more involved with the companies they contributed seed funding to.

Hear YC President and CEO Garry Tan talk about why he values earnesty and excellent communication skills in YC founders, his thoughts on AI, and more in this unexpectedly deep and in-depth interview.

In addition to cofounding Y Combinator and other companies before it, Paul Graham is a prolific writer and artist. He chronicled many of his thoughts while building Y Combinator in a series of dozens of candid essays, all of which you can read in an online archive.

Also known as a16z, the firm has invested in companies such as Airbnb, Facebook, and Lyft since its founding in 2009. A podcast episode offers a deep dive into how the firm got started and became the industry disruptor it is today.

Mark Zuckerberg became the youngest self-made billionaire in 2006 at 23 years old when Facebook held its initial public offering. In January of 2026, three AI startup founders—Brendan Foody, Adarsh Hiremath, and Surya Midha—broke Zuckerberg's record and became billionaires at 22 years old.

In 2013, the cofounders of DoorDash created a simple, homemade video application to Y Combinator. They didn't know it at the time, but they'd be accepted—and their company would go on to be publicly traded on the NASDAQ.

For years, Google was the cutting-edge of the AI world, including the development of the Transformer—the basis of contemporary AI chatbots. But since OpenAI debuted ChatGPT in 2022, the company was had to play catch-up. This is a four-hour deep dive into Google's AI history.

Two of Y Combinator's cofounders, Jessica Livingston and Paul Graham, were in a romantic relationship before they started the accelerator. They later married, and much later, Livingston started a podcast. In an episode of her podcast, Livingston and her cohost interview Graham about the beginning of YC and more.

That’s lower than the most elite universities and colleges in the world—but insiders have some tips about how applicants can have the best shot of being accepted to the selective startup accelerator.

The venture capital firm that kickstarted an industry.

Those programs, such as Y Combinator and Techstars, not only offer expert advice to founders, but also seed funding in exchange for equity. The goal is to help young startups learn from successful companies, making it more likely they attract venture capital.

During the three months that founders accepted into Y Combinator spend on YC’s California campus, they receive mentorship from YC partners, networking opportunities, and, overall, a ton of time to build and scale their companies.

Not all startup founders are created equal. This data visualization of the universities that produce the most startup founders is based on the number of alumni who have raised venture capital funding for their companies. That means these alums had to do much more than put "entrepreneur" in their LinkedIn bio to be considered startup founders.

Entrepreneur Shaan Puri shares how seven strangers acted as Google’s earliest angel investors. The first gave Google $100K without even putting his equity agreement in writing. The investors on “Shark Tank” use their personal funds to support startups, but they’re often more predatory about terms than typical angels.

Prior to Palantir's public listing in 2020, CEO Alex Karp did not give many interviews. In a rare interview from 2009, Karp discussed the dominance of American technology, his academic background, and the founding idea of Silicon Valley entrepreneurs as key players in aiding the fight against terrorism.

Y Combinator invests $500K into each company in any given batch. $125K of that investment converts into a fixed 7% in ownership of the startup, and the other $375K is invested on something called an uncapped MFN safe. YC explains what that means and more terms of the deal in a detailed article on their website

Tesla and X CEO Elon Musk, OpenAI CEO Sam Altman, LinkedIn founder Reid Hoffman, and others are getting into politics. From Musk’s role in President Trump’s second term to Hoffman’s spending on former Vice President Harris’ presidential campaign, more tech CEOs are expanding into politics. This podcast episode by WBUR and American Public Media discusses what the impact could be with so many tech figures engaging in American politics. Listen here.

Daniel Ha is a venture capitalist who built a suite of AI agents to boost his productivity, both professionally and personally. At his VC firm, a troupe of agents gathers data on startups and analyzes it from competing perspectives to produce a confidence score. When his dad was diagnosed with cancer, Ha used an oncology-trained AI to help him understand the condition.

Twitter began in 2006 as a side project and grew into a major global platform, widely used for news, activism, and political discourse. Despite mainstream success, it faced ongoing management turmoil, business struggles, and rising concerns over misinformation and user safety.

The level of startup funding around the world broke all previous records in Q1 2026 by a significant margin: Only $118B was raised in the previous quarter, and Q1's haul outpaced every full year of global VC activity before 2019. The increase was partly due to the enormous funding rounds from AI companies such as OpenAI and Anthropic.

Combined, the top seven companies by market cap in the US as of December 2024—Apple, Nvidia, Microsoft, Alphabet, Amazon, Meta, and Tesla—were worth more than $16T at the time.

Airbnb is arguably known as one of the most successful startup stories of all time. But back in 2008, many prominent investors rejected their pitch when they went out to raise money—and Airbnb's founder still has the rejection emails to prove it.