Dive deep into the numbers that shape each YC deal

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.

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.

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

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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 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.

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.

‘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.

Convertible notes represent loans that startups owe investors

In the second part of a two-part series, convertible notes are explained to be a tool angel investors use to ensure they see a return on their investment in a startup.

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

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.

Angel investors often receive significant equity because of the risk they take

Angel investors fund startups at an early stage, at which time a company’s success is less assured. In exchange, they often ask for a significant equity stake.

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+.

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.

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.

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.

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.

The Yale model of investment allocation, explained

College endowment managers long held to the traditional allocation of 60% domestic stocks and 40% bonds. But Yale’s David Swensen developed a new approach: deprioritizing low-risk fixed income and liquid assets in favor of alternative investments to leverage endowments' long-term investment horizons and capture the “liquidity premium.”

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.

How venture capital firms came to be

The venture capital firm that kickstarted an industry.

Angel investors often come together as a syndicate

Startups raise money in different rounds from investors that include their friends and family, angels, and venture capital funds. These types of investors serve different purposes.

A successful angel investor can multiply their investment by 3 to 10 times.

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.

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.

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.

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.