Y Combinator changed the way startups around the world are built

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.

Y Combinator tends to outperform many other Silicon Valley startup accelerators

In a podcast episode, Garry Tan—CEO of startup accelerator Y Combinator—speaks about how YC has a better track record than the rest of Silicon Valley at placing bets on startups. Learn how Tan earned his first million dollars, as well as lessons from other successful businesspeople, including Y Combinator’s Paul Graham.

Y Combinator takes its name from a computer science concept

Y Combinator, the startup accelerator, gets its name from the “Y combinator” computer science concept. Specifically, something called a “Y combinator” in computer science is a function that runs programs, just like the Y Combinator startup accelerator runs a program that helps grow startups.

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.

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.

Startups are small, early-stage companies designed to grow fast

The definition of the word “startup” is complicated—so who better to define it than Y Combinator, perhaps the most well-known startup accelerator in the business? YC’s blog also explains how startups make money and build products.

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.

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.

Where are the first batch of YC founders now?

Reddit was one of the companies in Y Combinator’s first batch. While OpenAI wasn’t among the companies started at YC, Sam Altman, who would later become the AI company’s CEO, had a different company called Loopt in the first batch.

‘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.

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.

Many startup founders pull out-of-the-box stunts to get their businesses off the ground

Do you know Airbnb’s founders used cereal (yes, as in the breakfast food) to secure their initial round of funding? Or that PayPal’s founders once gave out free money to get people to sign up for the platform? These stories might be crazy, but they’re not uncommon.

Airbnb's Brian Chesky explains 'Founder Mode' and how he took back control

The short-term rental CEO learned hard lessons through the pandemic, specifically around a culture focused on management and not building products. In the fall of 2024, Chesky gave a well-received speech at a startup conference that prompted debate in the startup world. He summarizes the talk here.

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.

WeWork marketed itself on community

In a new era of work where many millennials wanted to work for themselves in offices with exposed brick, cold brew on tap, and casual dress codes, WeWork realized these entrepreneurs and startup workers didn’t want to do it alone.

Burning Man’s countercultural messages have influenced Silicon Valley’s work culture

Burning Man is famous for attracting tech leaders like the CEOs of Tesla, Meta, and Google. Some experts believe the festival's ethos and principles of participation, communal effort and radical inclusion have given rise to Silicon Valley's communal work culture.

Many of the 2010s girlboss-era founders experienced a public fall from grace in 2020

In the 2010s, dozens of female founders were celebrated on the covers of business magazines like Inc. for their recent startup success, from Emily Weiss’s Glossier makeup brand to Steph Korey’s Away luggage company. But many of these companies were also the subject of large takedown articles around the year 2020.

Cyan Banister, once homeless, was an angel investor in Uber, SpaceX, and DeepMind

Cyan Banister has invested in more than 100 companies, building a reputation in the angel-investing world for her unorthodox approach.

Understanding TikTok-owner ByteDance's business model

ByteDance has ridden TikTok's major success to become the world's most valuable startup. This deep dive showcases some of the company's smartest moves and tactics, and where it's headed next.

Startup founders’ equity becomes diluted as they bring in more investors

When an angel investor funds a company in exchange for equity, startups issue new shares to them, rather than giving them existing shares, and boost the company’s valuation.

Steve Jobs changed the world with Apple and Pixar

The devices Jobs introduced during his time at Apple, including the iPad and iPhone, were imitated by competitors, ultimately helping to create the numerous options consumers have today. In addition to leading Apple, Jobs also helped turn Pixar and the software startup NeXT into success stories.

The venture capital mindset is shaping the US into a 'portfolio state'

For decades, the US has operated as a low-regulation, private-sector-driven, globalized economy (also known as neoliberalism). In recent years, the Trump administration has taken direct stakes (rather than providing subsidies) in private companies with strategic products like semiconductors and rare earths. This paper argues the approach allows the US to capture the upside of growth.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

Robinhood's pivot from everyday investors to hyperactive traders

The platform was conceived as a hub for first-time investors looking to get into trading. After criticism in 2021, the company pivoted to focus on more regular, daily traders, among whom the company's CEO has now become a cult hero.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

In 2020, Palantir moved its headquarters from Silicon Valley to Denver, CO

Despite being a famous tech startup synonymous with Silicon Valley, Palantir executives and cofounders have criticized tech founders for not taking a bigger role in upholding Western institutions and supporting American defense and intelligence work. That cultural tension is frequently cited as a motivating factor for the company's 2020 move to Denver, CO. In early 2026, the company announced another move to a suburb of Miami, FL.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

Fast-casual restaurant Chili's is experiencing a resurgence, with its parent company recently reporting a nearly 32% increase in sales, thanks to passionate Gen Z fans on TikTok.

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

Watch how algorithms can be designed to train themselves and self-improve without human input, to the point where the optimized code is too complex for programmers to understand.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Quincy Jones' 'Big Band Bossa Nova' helped introduce bossa nova—a jazz-influenced Brazilian genre—to the US

The US Constitution is widely regarded as the longest-standing written national constitution still in force—see how it has influenced rights worldwide.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.