Logo: Jessica Livingston http://ycombinator.com/, Public domain

Y Combinator

Startup accelerator that invests in early-stage companies in batches.

Startup acceleratorVenture capitalSeed fundingSilicon Valley

Active^{Source [7]}Last verified Oct 2, 2026

About Y Combinator

Y Combinator is a startup accelerator that invests in very early-stage companies in batches. It now runs its program four times a year, and the startups in each batch spend about three months in San Francisco working intensively with YC partners.^{Source [2]}^{Source [4]}

Its standard deal is a $500,000 investment per company: $125,000 for 7% on a post-money SAFE plus $375,000 on an uncapped SAFE with a most-favored-nation clause.^{Source [2]}

It was started in March 2005 by Paul Graham, Jessica Livingston, Robert Morris and Trevor Blackwell as the Summer Founders Program, and moved its batches to Silicon Valley that winter. Alumni include Airbnb, Stripe, Coinbase, DoorDash, Dropbox, Reddit and Instacart; YC says its companies have a combined valuation of $1.3 trillion.^{Source [1]}^{Source [4]}

Sam Altman, a founder in the first batch, led YC as president from 2014 to 2019. Geoff Ralston succeeded him in 2019, and Garry Tan has been president and CEO since January 2023.^{Source [5]}^{Source [3]}^{Source [6]}^{Source [7]}^{Source [8]}

What happened

Started in March 2005 by Paul Graham, Jessica Livingston, Robert Morris and Trevor Blackwell. Sam Altman, a founder in its first batch, became president in 2014, stepped down in March 2019 and was succeeded by Geoff Ralston in May 2019. It is still active, led by President and CEO Garry Tan.^{Source [1]}^{Source [5]}^{Source [3]}^{Source [6]}^{Source [7]}

Timeline

2023-01Garry Tan became president and CEO, succeeding Geoff Ralston.^{Source [8]}^{Source [7]}
2019-05Geoff Ralston named president; Sam Altman became an advisor.^{Source [6]}
2019-03Sam Altman stepped down as president; YC announced a move of its headquarters from Mountain View to San Francisco.^{Source [3]}
2015-12OpenAI started as part of YC Research, according to YC.^{Source [4]}
2014-02Paul Graham named Sam Altman president.^{Source [5]}
2005-12Funded its second batch in Silicon Valley and settled on running two batches a year.^{Source [1]}
2005-03Founded with $200,000 from its four founders; ran the first Summer Founders Program, whose batch included Reddit and Loopt.^{Source [1]}^{Source [4]}^{Source [9]}

Products and brands

YC accelerator program: Three-month program run four times a year with a $500,000 standard investment.^{Source [2]}
Startup School: Free online program and resources for founders.^{Source [4]}
Hacker News: Technology news and discussion site linked from YC's website.^{Source [4]}

How it makes money: Takes equity in the startups it funds through SAFEs and earns returns when those companies are acquired or go public.^{Source [2]}

Leadership

Garry Tan	President and CEO^{Source [7]}^{Source [8]}	Since 2023
Jared Friedman	Managing Partner^{Source [7]}
Diana Hu	Managing Partner^{Source [7]}
Harj Taggar	Managing Partner^{Source [7]}

Funding and financials

Combined valuation of YC companies: $1.3 trillion (YC website, October 2026)^{Source [4]}

People on Founded, and where they went next

1 person on record, connected to 7 other companies.

Person	Here	Also built
Sam Altman	President, Chairman, Partner2011 to 2019	Merge LabsActiveTools for Humanity2019 to nowActiveOpenAI2015 to nowActiveOklo2015 to 2025IPOHelion2015 to 2026ActiveHydrazine Capital2012ActiveLoopt2005 to 2012Acquired

Sources

How Y Combinator Started, Paul Graham, 2012-03. Accessed Oct 2, 2026.
About Y Combinator, Y Combinator. Accessed Oct 2, 2026.
Y Combinator president Sam Altman is stepping down amid a series of changes at the accelerator, TechCrunch, 2019-03-08. Accessed Oct 2, 2026.
Y Combinator, Y Combinator. Accessed Oct 2, 2026.
Sam Altman for President, Y Combinator, 2014-02-21. Accessed Oct 2, 2026.
Geoff Ralston for President, Y Combinator, 2019-05-20. Accessed Oct 2, 2026.
People, Y Combinator. Accessed Oct 2, 2026.
Y Combinator names Garry Tan as its next president, replacing Geoff Ralston in January 2023 (Forbes), Techmeme, 2022-08-29. Accessed Oct 2, 2026.
Loopt, Y Combinator. Accessed Oct 2, 2026.

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