The Y Combinator startup directory includes every company YC has funded

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

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.

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

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.

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.

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

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.

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

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.

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.

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.

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 and Harvard are among the universities producing the most startup founders

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.

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.

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.

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

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.

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.

Watch the DoorDash team's YC application video

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.

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.

The term 'startup'—which is typically used to describe private companies in their early stages of operation that focus on innovating new products or services to meet a market gap—can be traced back to a 1976 Forbes article.

‘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.

Global investing in startups hit a record $297B in Q1 2026

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.

In 2023, venture capital firms invested $170B in over 15,000 US companies

That's a significant drop from 2022’s $242B, reflecting market uncertainty but continuing VC’s role in scaling transformative ideas. Rooted in early risk-sharing models, venture capital took off with firms like ARDC in 1946, later evolving into today’s influential players like Sequoia Capital and Andreessen Horowitz.

Venture capital is a type of financing that firms and funds use to invest in startups they believe have the potential for long-term growth

Household name companies such as Airbnb and Uber might not exist without venture capital, which is commonly referred to as "VC" for short.

Nonprofit VC funds invest in startups, but have donors instead of LPs

Examples include Andreessen Horowitz’s TxO (Talent x Opportunity) Initiative and Fifth Star Funds, which allows donors to write “Friends & Family” checks for Black tech founders.

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.

Startups fundraise in 'rounds' as they prove out their business and scale

When startups take on outside funding, those investments are divided into different "rounds." These rounds are catered to different stages in a startup's life cycle—a startup often needs different types of investors and amounts of funding at different stages of the business. For instance, a pre-seed investment round can include investments ranging from about $25K to $500K, whereas a Series D investment can be hundreds of millions of dollars.

How venture capital firms came to be

The venture capital firm that kickstarted an industry.

The top 100 companies in Silicon Valley

Silicon Valley has pumped out some of the biggest companies in the world, including Apple, Meta, and Google. Thousands of companies operate in the area, ranging from valuations in the trillions to startups only worth thousands.

Platforms like AngelList help angel investors find startups to fund

Angel investors leverage their high net worths to fund seed-stage startups. While they could see high returns, investing in such an early company is a risk.

From 19th-century whalers to startup accelerators, venture capital has a pretty exciting history

While the aforementioned whaling industry has a lot of similarities to today’s venture fund models, the first modern venture capital firm wasn’t founded until 1946.

See a list of 2024’s top 10 VC firms

A list of the top 10 VC firms, like Sequoia Capital and Andreessen Horowitz, ranked by assets under management shows how those two firms stack up against their competitors—and what kinds of companies those competitors invest in.

The 50-100-500 rule: when a startup is no longer a startup

According to startup expert Alex Wilhelm, a company cannot be considered a startup if it generates revenue exceeding $50M, employs more than 100 people, and has a valuation of $500M or more. However, Wilhelm modified the rule in 2018 to $100M in revenue, over 500 employees, and a valuation of $2.5B or more.

Andreessen Horowitz is among the most well-known venture capital firms

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.

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

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.

Angel investors funded startups with nearly $28B in 2024

Statistics about the angel investing market show that billions are spent funding early-stage startups each year. Companies with more angel interest had higher success rates.

80% of a VC firm's returns come from 20% of the deals, per VC's 'power law'

Early-stage startups are highly risky investments. Many companies in a VC portfolio will not provide any significant return.

The infrastructure, talent, and markets of Silicon Valley make the high-tech region ideal for startups

The number of startup employees, founders, and investors who have flocked to Silicon Valley over the years makes the California region ideal for networking in the tech space. Plus, California’s laws and specific rules around trade secrets help founders of fledgling businesses in Silicon Valley feel protected.

Find out how venture capitalists make decisions

More than 30% of venture capital deals come from leads courtesy of a VC’s former colleagues or professional network. You can learn more about how venture capitalists decide which companies to invest in by reading this article.

Over 400 tech companies call Santa Barbara home

The city boasts a strong talent pipeline from UCSB, established tech companies like Sonos and Procore and dozens of startups. Search for any company in Santa Barbara with this regularly-updated directory.

Many startups now have shoes-off policies

This website keeps track of startups with "no-shoes" offices so you can browse a list of barefoot companies—plus, see which of them are hiring.

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 world’s top 20 cities for startups include San Francisco

In 2023, Singapore had the highest venture capital funding per capita in the world. But that doesn’t necessarily mean it’s the best place to have a startup. In 2023, PitchBook analyzed data to determine the world’s best startup city, including fundraising activity, venture capital deals, and exit value. San Francisco ranked as No. 1. See which other locales landed in the top 20 with this graphic.

'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.

2025 venture capital funding by destination, visualized

This chart's source, Dealroom, uses "breakout capital" to refer to funding rounds or companies in the $15M to $100M total funding range. It labels the startup stage as under $15M, and the scaleup stage as $100M+.

See the anatomy of a venture capital firm

Venture capital firms get the money they use to invest in companies from limited partners, also called LPs. It’s the general partner’s job to manage that money and invest it in the right startups.

'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.

View a list of companies owned by Google's parent company, Alphabet

These companies include Google subsidiaries like YouTube, the biggest online video sharing and streaming platform, Nest, which manufactures smart products like speakers and thermostats, and Waymo, the technology company developing self-driving cars.

The early success of Facebook made Mark Zuckerberg a college campus celebrity

Within 24 hours of launching in 2004, more than 1,200 Harvard students signed up to the platform, which quickly expanded to other Ivy League and Boston-area schools within months. By year's end, Zuckerberg left Harvard to run the company in California.