# Y Combinator

Y Combinator (YC) is an American startup accelerator and venture capital firm founded in 2005, known for funding early-stage companies including OpenAI and Anthropic. It has launched over 5,000 companies, with many achieving unicorn status.

Y Combinator, LLC (YC) is an American technology startup accelerator and venture capital firm launched in March 2005. It has been used to launch more than 5,000 companies, including notable startups such as Airbnb, Coinbase, Cruise, DoorDash, Dropbox, GOAT, Instacart, Reddit, Stripe, Scale AI, Deel, Helion Energy, Starcloud, Twitch, and Whatnot. Over 400 companies funded by YC are worth more than $100 million, and 100 are unicorns (valued at over $1 billion). Y Combinator is also the operator of Hacker News, a popular technology news and discussion forum.

The accelerator program began in Boston and Mountain View, relocated to San Francisco in 2019, and was entirely online during the COVID-19 pandemic. YC provides seed funding, mentorship, and networking opportunities to startups, culminating in a Demo Day where founders present to investors.

## History

Y Combinator was founded in 2005 by Paul Graham, Jessica Livingston, Robert Tappan Morris, and Trevor Blackwell. It initially ran concurrent programs in Cambridge, Massachusetts, and Mountain View, California. Operational complexities led to the consolidation of operations in Silicon Valley in January 2009, closing the Cambridge program.

In 2009, YC secured a $2 million investment led by Sequoia Capital, enabling increased annual funding for around 60 companies. Sequoia further supported YC in 2010 with an $8.25 million funding round. Kirsty Nathoo joined the team as an accountant and later became CFO in 2012. In 2011, Yuri Milner and SV Angel offered every YC company a $150,000 convertible note investment, later adjusted to $80,000 when the Start Fund was renewed.

Advisory roles were taken by Harj Taggar and Alexis Ohanian in 2010, with Paul Buchheit and Taggar becoming partners in November. Michael Seibel joined as a part-time partner in January 2013 and became full-time in 2014. In September 2013, YC began funding nonprofit organizations, starting with Watsi.

Sam Altman, who participated in YC's inaugural cohort in 2005, was appointed president by Paul Graham in 2014. Altman introduced a revised equity offering of $150,000 for a 7% stake. Peter Thiel served as a visiting partner from 2015 to 2017. In 2016, YC partners visited 11 countries to engage with global startup communities. Altman returned to the U.S. that summer to work on [OpenAI](https://www.wikiprompt.org/wiki/openai), with leadership delegated to Ali Rowghani and Michael Seibel for YC Continuity and YC Core, respectively.

In 2018, YC announced a new batch of startup schools, but a software glitch initially accepted all 15,000 applicants, then rejected them hours later. After outcry, YC accepted all 15,000 companies. Qi Lu briefly served as CEO of YC China in 2018, but the program was discontinued, later morphing into MiraclePlus.

Geoff Ralston succeeded Altman as president in 2019. During the COVID-19 pandemic, YC conducted its summer 2020 batch remotely. In January 2022, a revised standard deal of $500,000 was introduced, comprising $125,000 for 7% equity and $375,000 via an uncapped safe with a Most Favored Nation clause. The summer 2022 batch saw a deliberate 40% reduction in startup intake, from 414 to 250 companies.

In January 2023, Garry Tan became president and CEO, succeeding Ralston, and discontinued the YC Continuity growth fund. YC moved its headquarters from Mountain View to San Francisco in spring 2023. In March 2024, Michael Seibel stepped down as managing director, succeeded by Jared Friedman. On March 30, 2026, YC announced its fastest unicorn to date: Starcloud raised a $170M Series A at a $1.1 billion valuation, led by Benchmark and EQT Ventures, 17 months after Demo Day.

## Programs

Y Combinator interviews and selects four batches of companies per year. Each company receives $500,000 in seed money, consisting of $125,000 on a post-money SAFE for 7% equity and $375,000 on an uncapped SAFE with a Most Favored Nation provision. Non-profits receive a $100,000 donation. The program includes office hours, where founders meet individually and in groups, and weekly meetups with guest speakers from the Silicon Valley ecosystem.

The program teaches founders how to market products, refine teams and business models, achieve product/market fit, and scale into high-growth businesses. It culminates in Demo Day, where startups present to potential investors.

Y Combinator also operates additional programs: the Series A Program, YC Post-A Program, and YC Growth Program, which support fast-growing startups and those raising Series B funding of $20 million to $100 million.

### Additional Programs

In July 2015, YC introduced the YC Fellowship Program for earlier-stage companies. The first batch included 32 companies receiving equity-free grants. In January 2016, the program changed to provide $20k investment for a 1.5% equity stake, structured as a convertible security that converts only upon an IPO or a funding event valuing the company at $100 million or more. The fellowship was discontinued in 2017.

In October 2015, YC introduced the YC Continuity Fund, which allowed pro rata investments in YC companies during later funding rounds. The fund was discontinued under Garry Tan's leadership in 2023.

## Impact and Notable Companies

Y Combinator has funded a wide range of successful startups across various sectors. In the [artificial-intelligence](https://www.wikiprompt.org/wiki/artificial-intelligence) space, YC has backed companies like [OpenAI](https://www.wikiprompt.org/wiki/openai) and [Anthropic](https://www.wikiprompt.org/wiki/anthropic), both of which have become major players in [generative-ai](https://www.wikiprompt.org/wiki/generative-ai) and [large-language-model](https://www.wikiprompt.org/wiki/large-language-model) development. Other notable AI-related startups include Scale AI, which provides data labeling for machine learning, and Cruise, which focuses on autonomous vehicles.

The accelerator has also supported companies in other domains, such as Airbnb (hospitality), Stripe (fintech), and Reddit (social media). YC's alumni network is extensive, with many founders going on to become influential figures in technology.

## Global Reach and Online Education

In 2016, YC partners visited 11 countries, including India, Israel, Nigeria, Denmark, Portugal, Sweden, Germany, Russia, Argentina, Chile, and Mexico, to engage with founders and learn about international startup communities. This global outreach led to the creation of Startup School in 2017, an online program offering courses and personalized coaching. Over 1,500 startups graduated in its first year.

In 2018, after a software glitch, YC accepted all 15,000 applicants to Startup School, demonstrating its commitment to supporting entrepreneurs worldwide. The program continues to provide resources for founders, though it has evolved over time.

## Leadership and Evolution

Y Combinator's leadership has evolved significantly since its founding. Paul Graham served as the initial leader until 2014, when Sam Altman took over as president. Altman's tenure saw the introduction of new programs and a focus on [artificial-intelligence](https://www.wikiprompt.org/wiki/artificial-intelligence) and other frontier technologies. Geoff Ralston led from 2019 to 2023, navigating the pandemic and remote operations. Garry Tan became president and CEO in 2023, bringing a new vision and discontinuing the YC Continuity fund.

The organization has adapted to changing market conditions, such as reducing batch sizes in 2022 and moving to San Francisco in 2023. YC's model of providing seed funding, mentorship, and a strong network has made it one of the most influential startup accelerators globally.

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Source: https://www.wikiprompt.org/wiki/y-combinator
License: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/)
Last updated: 2026-09-05T13:23:25.587035+00:00