During YC
Sam was part of YC's inaugural batch in S05 and founded OpenAI as YC Research in 2015.
During YC
Brian, Joe, and Nate did YC in W09.
During YC
The Collison brothers did YC twice—first in W07 and then in S09, when they started Stripe.
During YC
Fred and Brian met on Reddit and did YC in S12.
During YC
Andy, Stanley, Tony, and Evan did YC in S13.
During YC
Alexandr and Lucy did YC S16 and pivoted during the batch.
During YC
Arash and Drew started Dropbox at MIT and did YC in S07.
During YC
Alexis and Steve were in the inaugural YC batch in S05.
During YC
Apoorva, Max, and Brandon did YC in S12.
During YC
Sid and Dmytro did YC in S14.
During YC
Tarek and Luana did YC in W19.
During YC
Amjad and Haya interviewing for the YC W18 batch.
During YC
Michael, Justin, Kyle, and Emmett in YC W07.
OpenAI
Airbnb
Stripe
Coinbase
DoorDash
Scale AI
Dropbox
Instacart
GitLab
Kalshi
Replit
Twitch
$1.3 Trillionin combined valuation
Now
Sam built OpenAI into a $500B company.
Now
Airbnb went public in 2020 at an over $100B valuation.
Now
Stripe is now the internet’s $107B payments backbone.
Now
Coinbase went public in 2021 at a $86B valuation.
Now
DoorDash went public in 2020 at a valuation of $39B.
Now
In 2025, Meta acquired 49% of Scale for over $14B.
Now
Dropbox had the biggest tech IPO of 2018 at a $9B valuation.
Now
Reddit went public in 2024 at a $6.4B valuation.
Now
Instacart went public in 2023 at a $10B valuation.
Now
GitLab went public in 2021 at an $11B valuation.
Now
Kalshi reached an $11B valuation in 2025.
Now
Replit became a leading AI coding platform valued at over $3B.
Now
Twitch was acquired by Amazon for nearly $1B.
In 2005, Y Combinator developed a new model of startup funding. Four times a year we invest $500k in a select group of startups. They move to San Francisco for three months, where we work intensively with them to get the company into the best possible shape, before they present to a large audience of investors on Demo Day.
But YC doesn’t end on Demo Day. We and the YC alumni network continue to help founders for the life of their company, and beyond.
YC compresses months of growth into weeks.The sense of urgency is so infectious among founders that it becomes the most productive period in most people’s lives.
It’s a community of founders that you can’t find anywhere else.It feels like having the entire world at your back—from Partners to batchmates.
Being surrounded by the top 1% of founders in the world just completely resets the bar.You leave with a completely new sense of how fast ‘fast’ can be.
It's never too early to apply.
We fund companies with no revenue, product, or fully baked idea.