Y Combinator cofounder Paul Graham keeps a public archive of his insightful essays

Y Combinator was founded in 2005 to bridge gaps between founders and investors

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.

Read Paul Graham’s initial post announcing YC’s first batch

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

Y Combinator cofounder, Jessica Livingston, once interviewed her husband and cofounder, Paul Graham

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.

Y Combinator, the startup accelerator, gets its name from the 'Y combinator' computer science concept.

YC was partly inspired by an investor named Julian Weber

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.

Stanford’s ‘How to Start a Startup’ series

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.

Y Combinator changed the way startups around the world are built

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.

CEO Gary Tan explains Y Combinators guiding philosophy

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.

'Founder mode' is the idea that founders should take a hands-on approach to running their businesses

In 2024, Y Combinator Cofounder Paul Graham wrote a viral manifesto of sorts about a strategy he calls "founder mode." It's the opposite of what Graham calls "manager mode," which allows founders to hire executives who he says ultimately run the company into the ground.

For Reddit's founders, the company's early days included choosing a dinner with Y Combinator's Paul Graham over a spring break trip, a $10M Condé Nast acquisition, and other pivotal moments.

'Founder mode' is the idea that startup founders should take a hands-on approach to running their businesses

In 2024, Y Combinator cofounder Paul Graham popularized the idea of "founder mode" when he wrote a viral manifesto in response to a talk that Airbnb CEO Brian Chesky gave about leadership styles. Graham positioned the concept of founder mode as the opposite of manager mode—when founders hire executives and middle managers to run their companies and make decisions that Graham says are better left to founders.

Listen to a podcast episode where Y Combinator CEO Gary Tan explains why YC tends to outperform many other Silicon Valley startup accelerators.

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

Yahoo acquired Paul Graham's former startup Viaweb in 1998

Viaweb was the web app tech startup that Paul Graham, Robert Morris, and Trevor Blackwell cofounded before they started Y Combinator. The company sold for $49M and Viaweb was rebranded as the Yahoo Store.

The Y Combinator startup directory includes every company YC has funded

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.

Y Combinator has a roughly 1% acceptance rate

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.

Startup accelerators that include more training activities, such as pitch competitions, tend to have better long-term success rates

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.

Mark Zuckerberg credits some of Facebook's success to constant evolution

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.

Benjamin Graham is known as the 'father of value investing'

Graham was an investor, author, and professor who was also Warren Buffett's teacher and mentor during his time at Columbia University. Graham is still considered one of the most influential people in the world of investing today.

'In my experience, each failure contains the seeds of your next success—if you are willing to learn from it.'

- Microsoft cofounder Paul Allen (1953–2018)

Explore the schedule of a three-month YC batch

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.

Watch a rare early interview with Palantir CEO Alex Karp

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.

3 out of Palantir's 5 cofounders once served as editor-in-chief of The Stanford Review

After Peter Thiel founded the conservative student newspaper, he remained involved and invested in the paper's success. Other Palantir cofounders, Joe Lonsdale and Stephen Cohen, also both previously served as the paper's editor-in-chief.

Read an email Steve Jobs wrote himself in 2010

Steve Jobs apparently liked to email himself to save his thoughts. This archival email, written the year before he died, shows Jobs expressing gratitude and wonder for the world and its creative people.

Read Sam Altman's life advice that he wrote in a blog post before he became CEO of OpenAI, from "don't lose touch with old friends" to "occasionally stay up until the sun rises talking to people."

Dive deep into the numbers that shape each YC deal

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

Vitalik Buterin’s current thoughts on Ethereum

Vitalik Buterin isn’t just the founder of Ethereum—he’s also a blogger. In this blog post from late last year, Buterin discusses some of his favorite applications built on Ethereum: prediction markets like Polymarket, where users can bet crypto on the outcome of events like elections. Buterin argues that prediction markets also act as news sites for non-bettors, opening the floodgates for many different kinds of info-based apps on Ethereum. Read the post here.

Amazon sends its first-ever letter to shareholders every year

The first letter to Amazon’s shareholders, written by founder and then-CEO Jeff Bezos in 1997, is a key part of the Amazon story—laying out the company’s long-term approach to the business and several of its core operating values. Bezos emphasizes, for example, Amazon’s plan to start with a bookstore but to evolve into a much larger ecosystem.

The dot-com stock bubble taught Howard Marks about markets

Annual investment letters from Howard Marks, the billionaire cofounder of top distressed debt shop Oaktree Capital Management, are required reading on Wall Street. The prolific writer and investor explains the distinction between the folly of trying to time the market and the necessity of paying attention to market cycles. The difference makes all the difference in returns.

Startup accelerators offer mentorship and seed funding in exchange for equity

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.

87% of the startups in Y Combinator’s Fall 2025 batch were AI companies

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.

ChatGPT was conceived over dinner at a Silicon Valley hotel.

Amazon founder Jeff Bezos emphasizes worrying about customers rather than competition

In a 1999 shareholder letter, Bezos wrote, "I constantly remind our employees to be afraid, to wake up every morning terrified. Our customers have made our business what it is, and we consider them to be loyal to us – right up until the second that someone else offers them a better service." Motivated by fear, the entrepreneur advocates consistent innovation, experimentation, and improvement to create a better customer experience.

Read Palantir CEO Alex Karp's most recent shareholder letter

Alex Karp's latest shareholder letter details both the company's outlook and recent performance, but also provides insight into what leadership finds important more generally. In this letter, Karp addresses Palantir critics and external concerns about the use of Palantir's technology for government surveillance.

Legendary venture capitalist Peter Thiel once wrote that 'competition is for losers'

With Peter Thiel's "Monopoly Theory," the Founders Fund partner argued that investing in companies that create new categories, rather than those that compete with other businesses in existing ones, is a best practice in venture capital.

Listen to a conversation between two Palantir cofounders—Peter Thiel and Joe Lonsdale

Palantir cofounder Joe Lonsdale was an editor of the Stanford Review (which Peter Thiel founded), and Thiel became a mentor to Lonsdale. The two discussed shared sentiments about the importance of developing Palantir to maintain a largely American global order, as well as cultural revolutions.

Read Berkshire Hathaway shareholder letters from 1977 on

Each year, Berkshire Hathaway’s shareholder letters are eagerly anticipated by employees and Buffett fans alike. A resource lists every single letter from 1977 and is great for anyone seeking a peek behind the curtain into Buffett’s brain through years of stock market booms and busts.

Read about how one of Palantir's cofounders explains the company's founding

Palantir cofounder Joe Lonsdale described the company's driving principle as fighting terrorism in a blog post marking its IPO. Lonsdale also said Palantir's software was developed with a keen focus on privacy, despite many allegations that it enables government surveillance.

Jim Simons, mathematician turned government codebreaker turned trader, revolutionized quantitative investing

The late Jim Simons is remembered as one of the most successful (and profitable) hedge fund managers of all time. He went from physically gathering microfilm on commodities pricing decades ago to overseeing a firm that led Wall Street in daily trading volume.

David Ogilvy—one of history's most famous and influential advertising executives—wrote multiple books, including 'Ogilvy on Advertising,' a career memoir full of his favorite copywriting advice.

Google's early focus on simplicity and user experience drove its future successes

Google Search revolutionized information retrieval in 1998, but additional web-based products, including Gmail, Maps, Docs, and YouTube reinforced the company's core ad business while allowing it to aggregate the world's information. Forming Alphabet protected this business from riskier moonshot projects.

7 angel investors funded Google in its early days

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.

'My model for business is The Beatles: They were four guys that kept each others' negative tendencies in check; they balanced each other. And the total was greater than the sum of the parts.'

-Apple co-founder Steve Jobs (1955-2011)

A Grateful Dead online bulletin board system inspired the early internet and counted some of tech's biggest names, like Apple's Steve Wozniak, as users.

Read more about Palantir cofounder Peter Thiel's political beliefs and activity

At Stanford University, Thiel founded "The Stanford Review," a libertarian magazine dedicated to being against "political correctness." Since then, Thiel has railed against American universities as failing institutions, given lectures about the coming of the Antichrist, and donated money to high-profile political campaigns (including those of President Donald Trump and Vice President JD Vance).

‘Demo days’ are when founders at Y Combinator pitch their startup ideas

Investors sit in the audience, waiting to hear what this season’s batch of YC founders have cooked up. YC argues that going through the process of a demo day can help founders get a better understanding of their startup themselves.

The Wall Street Journal compiled the best parts of Warren Buffett's annual letters

Over the years, Buffett has quoted Yogi Berra and Mae West, as well as country songs and the Bible. Many turn to his letters as a source of inspiration and wisdom.

Startups follow a 'minimum viable product' strategy to determine demand

Michael Seibel, group partner for startup incubator Y Combinator, explains how to build a minimum viable product (also known as an MVP) for any startup idea. Using real companies that experienced the Y Combinator program as examples, he walks through how to determine an MVP feature set, how to present an MVP to potential investors, and more.

Elon Musk's will to launch: the early days of SpaceX

Radically reducing the cost of rockets and innovating totally new space vehicles originated in the singular force of Elon Musk's vision. In this podcast, Founders creator David Senra shares what he learned reading a book about SpaceX's beginnings, highlighting Musk's audacious refusal to follow industry conventions and promotion of a culture of action and speed. Learn more insights from the founder here.

Peter Thiel and Elon Musk formed PayPal after merging two dot-com companies

Elon Musk cofounded "X.com," an online banking service, in 1999 with the idea that the web would become a financial repository as internet access expanded and became ingrained in daily life. Peter Thiel cofounded "Confinity" as a digital security service that morphed into a payments system. In 2000, the two merged to form PayPal, and in 2002, they sold PayPal to eBay for $1.5B.