# Y Combinator

Four people started an accelerator in 2005. Twenty years on, a third of its partners are founders it funded.

Source: https://netgraf.isik.co/m/y-combinator
Kind: Real
Summary: 41 people, 59 relationships, 1964 to 2024
Structure: average 2.7 connections each, 7% of the possible ties drawn, 7 communities, 2 separate groups

## People (41)

- Trevor Blackwell, YC co-founder, roboticist, from 1969
- Robert Tappan Morris, YC co-founder, MIT professor, from 1965
- Paul Graham, YC co-founder, president 2005 to 2014, from 1964
- Jessica Livingston, YC co-founder, from 1971
- Sam Altman, President 2014 to 2019, then OpenAI, from 1985
- Geoff Ralston, President 2019 to 2023
- Garry Tan, President and CEO since 2023. Founded Posterous, from 1981
- Carolynn Levy, Managing director for legal. Wrote the SAFE
- Kirsty Nathoo, Chief financial officer
- Paul Buchheit, Built Gmail, then a YC partner, from 1977
- Michael Seibel, Justin.tv founder, managing director to 2024, from 1982
- Jared Friedman, Scribd founder, managing director from 2024
- Diana Hu, Escher Reality founder, managing partner
- Harj Taggar, Auctomatic and Triplebyte founder, partner
- Tom Blomfield, Founded GoCardless and Monzo, from 1985
- Gustaf Alströmer, Ran growth at Airbnb
- Nicolas Dessaigne, Founded Algolia
- Pete Koomen, Founded Optimizely
- Andrew Miklas, Founded PagerDuty
- David Lieb, Founded Bump, sold to Google
- Tyler Bosmeny, Founded Clever
- Steve Huffman, Reddit, the first batch, from 1983
- Alexis Ohanian, Reddit, the first batch, from 1983
- Drew Houston, Dropbox, S07, from 1983
- Arash Ferdowsi, Dropbox, S07, from 1985
- Justin Kan, Justin.tv, S07, from 1983
- Emmett Shear, Justin.tv, then Twitch CEO, from 1983
- Kyle Vogt, Justin.tv, then founded Cruise, from 1982
- Patrick Collison, Auctomatic W07, then Stripe, from 1988
- John Collison, Auctomatic W07, then Stripe, from 1990
- Brian Chesky, Airbnb, W09, from 1981
- Joe Gebbia, Airbnb, W09, from 1981
- Nathan Blecharczyk, Airbnb, W09, from 1983
- Brian Armstrong, Coinbase, S12, from 1983
- Fred Ehrsam, Coinbase, S12, from 1988
- Tony Xu, DoorDash, S13, from 1985
- Peter Thiel, Backed Stripe out of the PayPal Mafia, from 1967
- Aaron Swartz, Infogami, merged into Reddit, 1986 to 2013
- Stanley Tang, DoorDash, S13, from 1992
- Andy Fang, DoorDash, S13
- Evan Moore, DoorDash, S13

## Relationships (59)

- Paul Graham and Jessica Livingston: co-founded YC with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Paul Graham and Robert Tappan Morris: co-founded YC with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Paul Graham and Trevor Blackwell: co-founded YC with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Jessica Livingston and Robert Tappan Morris: co-founded YC with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Jessica Livingston and Trevor Blackwell: co-founded YC with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Robert Tappan Morris and Trevor Blackwell: co-founded YC with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Paul Graham and Jessica Livingston: married to (family, confirmed, from 2008) [source: https://en.wikipedia.org/wiki/Jessica_Livingston]
- Paul Graham and Robert Tappan Morris: co-founded Viaweb with (business, confirmed, 1995 to 1998) [source: https://en.wikipedia.org/wiki/Viaweb]
- Paul Graham and Trevor Blackwell: co-founded Viaweb with (business, confirmed, 1995 to 1998) [source: https://en.wikipedia.org/wiki/Viaweb]
- Robert Tappan Morris and Trevor Blackwell: Viaweb together (business, confirmed, 1995 to 1998) [source: https://en.wikipedia.org/wiki/Viaweb]
- Paul Graham -> Sam Altman: handed him the presidency (business, confirmed, 2014) [source: https://en.wikipedia.org/wiki/Sam_Altman]
- Sam Altman -> Geoff Ralston: succeeded by (business, confirmed, 2019) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Geoff Ralston -> Garry Tan: succeeded by (business, confirmed, 2023) [source: https://en.wikipedia.org/wiki/Garry_Tan]
- Paul Graham -> Michael Seibel: brought him in as a part time partner (business, confirmed, 2013) [source: https://www.ycombinator.com/people]
- Sam Altman -> Michael Seibel: partner under him (business, confirmed, 2014 to 2019) [source: https://www.ycombinator.com/people]
- Michael Seibel -> Jared Friedman: handed over as managing director (business, confirmed, 2024) [source: https://www.ycombinator.com/people]
- Garry Tan -> Diana Hu: managing partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> Harj Taggar: managing partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Paul Graham -> Paul Buchheit: partner (business, confirmed, from 2010) [source: https://www.ycombinator.com/people]
- Paul Graham -> Kirsty Nathoo: chief financial officer (business, confirmed, from 2010) [source: https://www.ycombinator.com/people]
- Paul Graham -> Carolynn Levy: wrote YC's legal paperwork (business, confirmed, from 2013) [source: https://www.ycombinator.com/people]
- Garry Tan -> Tom Blomfield: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> Gustaf Alströmer: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> Nicolas Dessaigne: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> Pete Koomen: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> Andrew Miklas: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> David Lieb: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Garry Tan -> Tyler Bosmeny: general partner under him (business, confirmed, from 2023) [source: https://www.ycombinator.com/people]
- Steve Huffman and Alexis Ohanian: co-founded Reddit with (business, confirmed, from 2005) [source: https://en.wikipedia.org/wiki/Reddit]
- Paul Graham -> Steve Huffman: funded them in the very first batch (business, confirmed, 2005) [source: https://en.wikipedia.org/wiki/Reddit]
- Paul Graham -> Alexis Ohanian: funded them in the very first batch (business, confirmed, 2005) [source: https://en.wikipedia.org/wiki/Reddit]
- Aaron Swartz -> Steve Huffman: merged Infogami into Reddit (business, confirmed, 2006) [source: https://en.wikipedia.org/wiki/Aaron_Swartz]
- Aaron Swartz -> Alexis Ohanian: merged Infogami into Reddit (business, confirmed, 2006) [source: https://en.wikipedia.org/wiki/Aaron_Swartz]
- Paul Graham -> Garry Tan: funded Posterous, S08 (business, confirmed, 2008) [source: https://en.wikipedia.org/wiki/Garry_Tan]
- Drew Houston and Arash Ferdowsi: co-founded Dropbox with (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Dropbox]
- Paul Graham -> Drew Houston: funded Dropbox, S07 (business, confirmed, 2007) [source: https://en.wikipedia.org/wiki/Dropbox]
- Justin Kan and Emmett Shear: co-founded Justin.tv with (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Justin.tv]
- Justin Kan and Michael Seibel: co-founded Justin.tv with (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Justin.tv]
- Justin Kan and Kyle Vogt: co-founded Justin.tv with (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Justin.tv]
- Emmett Shear and Michael Seibel: Justin.tv together (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Justin.tv]
- Emmett Shear and Kyle Vogt: Justin.tv together (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Justin.tv]
- Michael Seibel and Kyle Vogt: Justin.tv together (business, confirmed, from 2007) [source: https://en.wikipedia.org/wiki/Justin.tv]
- Drew Houston and Justin Kan: batchmates in S07 (social, confirmed, 2007) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Arash Ferdowsi and Emmett Shear: batchmates in S07 (social, confirmed, 2007) [source: https://en.wikipedia.org/wiki/Y_Combinator]
- Patrick Collison and John Collison: co-founded Stripe with (business, confirmed, from 2009) [source: https://en.wikipedia.org/wiki/Stripe,_Inc.]
- Harj Taggar and Patrick Collison: co-founded Auctomatic with, W07 (business, confirmed, 2007 to 2008) [source: https://www.ycombinator.com/people]
- Harj Taggar and John Collison: co-founded Auctomatic with, W07 (business, confirmed, 2007 to 2008) [source: https://www.ycombinator.com/people]
- Peter Thiel -> Patrick Collison: backed Stripe early (business, confirmed, from 2010) [source: https://en.wikipedia.org/wiki/Stripe,_Inc.]
- Brian Chesky and Joe Gebbia: co-founded Airbnb with (business, confirmed, from 2008) [source: https://en.wikipedia.org/wiki/Airbnb]
- Brian Chesky and Nathan Blecharczyk: co-founded Airbnb with (business, confirmed, from 2008) [source: https://en.wikipedia.org/wiki/Airbnb]
- Joe Gebbia and Nathan Blecharczyk: co-founded Airbnb with (business, confirmed, from 2008) [source: https://en.wikipedia.org/wiki/Airbnb]
- Paul Graham -> Brian Chesky: funded Airbnb, W09 (business, confirmed, 2009) [source: https://en.wikipedia.org/wiki/Airbnb]
- Gustaf Alströmer -> Brian Chesky: ran growth for him (business, confirmed, 2012 to 2017) [source: https://www.ycombinator.com/people]
- Brian Armstrong and Fred Ehrsam: co-founded Coinbase with (business, confirmed, from 2012) [source: https://en.wikipedia.org/wiki/Coinbase]
- Fred Ehrsam -> Steve Huffman: the two met through Reddit (social, reported, 2012) [source: https://en.wikipedia.org/wiki/Coinbase]
- Tony Xu and Stanley Tang: co-founded DoorDash with (business, confirmed, from 2013) [source: https://en.wikipedia.org/wiki/DoorDash]
- Tony Xu and Andy Fang: co-founded DoorDash with (business, confirmed, from 2013) [source: https://en.wikipedia.org/wiki/DoorDash]
- Tony Xu and Evan Moore: co-founded DoorDash with (business, confirmed, from 2013) [source: https://en.wikipedia.org/wiki/DoorDash]
- Stanley Tang and Andy Fang: co-founded DoorDash with (business, confirmed, from 2013) [source: https://en.wikipedia.org/wiki/DoorDash]

## Tour (5 steps)

1. March 2005. Paul Graham and Jessica Livingston start an accelerator with Graham's two Viaweb co-founders. The first batch takes eight companies out of about 225.
2. One of those eight was Reddit. Graham funded Steve Huffman and Alexis Ohanian, then folded Aaron Swartz's Infogami into it the following year.
3. The presidency changed hands three times, never to an outsider: Graham to Sam Altman, Altman to Geoff Ralston, Ralston to Garry Tan.
4. S07 is the batch that keeps paying out. Dropbox came from it, and so did Justin.tv, whose four founders became Twitch, Cruise and a managing director of YC itself.
5. The partners are mostly alumni now. Harj Taggar was in W07 with the Collisons, Tom Blomfield built Monzo, Pete Koomen built Optimizely.

## Sources

- https://en.wikipedia.org/wiki/Y_Combinator
- https://en.wikipedia.org/wiki/Jessica_Livingston
- https://en.wikipedia.org/wiki/Viaweb
- https://en.wikipedia.org/wiki/Sam_Altman
- https://en.wikipedia.org/wiki/Garry_Tan
- https://www.ycombinator.com/people
- https://en.wikipedia.org/wiki/Reddit
- https://en.wikipedia.org/wiki/Aaron_Swartz
- https://en.wikipedia.org/wiki/Dropbox
- https://en.wikipedia.org/wiki/Justin.tv
- https://en.wikipedia.org/wiki/Stripe,_Inc.
- https://en.wikipedia.org/wiki/Airbnb
- https://en.wikipedia.org/wiki/Coinbase
- https://en.wikipedia.org/wiki/DoorDash