Personnel Analysis: Y Combinator Venture Capital Firm


Below are the Y Combinator partners, the people that decide YC applications and advise startups. In addition to these people, YC alumni also frequently sit in on interviews and influence the decision-making process.

Partners That Advise Full-Time

Name Description
Paul Graham
Paul Graham Forbes Hackers & Painters ANSI Common Lisp On Lisp

Paul Graham is a programmer, venture capitalist, and essayist. He is known for his work on Lisp, for co-founding Viaweb (which eventually became Yahoo! Store), and for co-founding the Y Combinator seed capital firm. He is the author of On Lisp (1993), ANSI Common Lisp (1995), and Hackers & Painters (2004). In 1995, Graham and Robert Morris founded Viaweb, the first application service provider (ASP). Viaweb’s software, originally written mostly in Common Lisp, allowed users to make their own Internet stores. In the summer of 1998 Viaweb was sold to Yahoo! for 455,000 shares of Yahoo! stock, valued at $49.6 million. At Yahoo! the product became Yahoo! Store.

He has since begun writing essays for his popular website They range from “Beating the Averages“, which compares Lisp to other programming languages and introduced the word Blub, to “Why Nerds are Unpopular“, a discussion of nerd life in high school. A collection of his essays has been published as “Hackers & Painters” by O’Reilly.

In 2005, after giving a talk at the Harvard Computer Society later published as How to Start a Startup, Graham along with Trevor Blackwell, Jessica Livingston and Robert Morris started Y Combinator to provide seed funding to startups, particularly those started by younger, more technically-oriented founders. Y Combinator has now invested in more than 500 startup companies.

BusinessWeek included Paul Graham in 2008 edition of its annual feature, The 25 Most Influential People on the Web. Graham has a B.A. from Cornell. He earned an M.S. and a Ph.D. in Applied Sciences (specializing in computer science) from Harvard in 1988 and 1990 respectively, and studied painting at Rhode Island School of Design and the Accademia di Belle Arti in Florence. In 2008, Paul Graham married Jessica Livingston. In 2010, Paul Graham was featured on the cover of Forbes magazine.

Paul Buchheit Paul Buchheit is an American computer programmer and entrepreneur. He was the creator and lead developer of Gmail. He developed the original prototype of Google AdSense as part of his work on Gmail. He also suggested the company’s now-famous motto “Don’t be evil” in a 2000 meeting on company values.Buchheit was a founder of the startup FriendFeed, which was launched in 2007 and was acquired by Facebook in 2009. In 2010, Buchheit left Facebook to become a partner at the venture capital firm Y Combinator. From 2006 (when he started investing) through 2008, Paul invested about $1.21 million in 32 different companies. He also continues to oversee angel investments of his own, in (by his own estimate) “about 40″ startups.
Kevin Hale Kevin Hale is the co-founder of Wufoo, from Y Combinator’s second batch in Winter 2006. Wufoo was acquired by SurveyMonkey in 2011. As a child, Kevin was the kid in class who ate a box of crayons for a dollar.
Carolynn Levy Carolynn Levy is a corporate attorney. Prior to Y Combinator, she was an associate in the corporate and securities practice at Wilson Sonsini Goodrich & Rosati. At Wilson Sonsini Goodrich & Rosati, Ms. Levy’s practice primarily focused on advising both public and private companies on a broad range of securities laws and other issues. This included representing clients in a wide variety of transactions, including equity private placements, mergers and acquisitions, asset sales, strategic alliances, and public equity offerings. Additionally, Carolynn Levy has extensive experience counseling both public and private clients on general corporate and compliance matters.
Aaron Iba Aaron Iba is the co-founder of AppJet, an online programming tool for building simple web apps in Javascript. AppJet was acquired by Google in 2009.
Jessica Livingston Founders At WorkJessica Livingston is an author and a founding partner of the seed stage venture firm Y Combinator. She also organizes Startup School. She has a B.A. in English from Bucknell University. In early 2007, Livingston released Founders at Work: Stories of Startups’ Early Days (published by Apress), a collection of interviews with famous startup founders, including Steve Wozniak (Apple), Mitch Kapor (Lotus), Ray Ozzie (Lotus), and Max Levchin (PayPal). In 2008, she married fellow Y Combinator co-founder Paul Graham.
Kirsty Nathoo Kirsty Nathoo is Y Combinator’s Vice President of Finance and Operations. Prior to Y Combinator, Ms. Nathoo was an audit manager at accounting firm Price Waterhouse Coopers. Kirsty Nathoo’s formal education consists of a Masters degree in Information Engineering from the University of Cambridge.

Kirsty Nathoo is Y Combinator’s secret weapon of finance and operations.

Geoff Ralston Geoff Ralston has been an investor in, board member of, and advisor to a variety of start-up companies, mostly in the San Francisco Bay Area. Most recently, Geoff was the chief executive officer of Lala Media, Inc., an innovative cloud music start-up in Palo Alto which was purchased by Apple in December of 2009. Geoff worked at Yahoo! from 1997-2005 after their 1997 acquisition of Four11 Corp. At Four11 Geoff was the VP of Engineering and led the creation of Yahoo! Mail’s predecessor, RocketMail. At Yahoo! Geoff was Senior Vice President and general manager of the Communications Business Unit and then served as the company’s Chief Product Officer from 2003-2005. Prior to Four11, Geoff was the creator of the popular LookUP! Internet white pages and do-it-yourself home page service. Geoff holds a BA in Computer Science from Dartmouth College , an MS in Computer Science from Stanford University , and an MBA from INSEAD, the European Institute of Business Administration.


Partners That Advise Part-Time

Name Description
Sam Altman Sam Altman is a co-founder and CEO of Loopt, a location-based social networking mobile application. Loopt was founded during Altman’s sophomore year at Stanford University, where he studied computer science with a focus on security and machine learning. Altman sold Loopt to Green Dot Corporation in 2012 for $43.4 million. At Stanford, Sam Altman helped build an autonomous helicopter navigation system.Sam Altman is a part-time partner at Y Combinator. In 2008, Mr. Altman was named by BusinessWeek as one of the “Best Young Entrepreneurs in Technology”. Paul Graham lists Sam Altman as one of the most interesting five startup founders in the last 30 years.
Dalton Caldwell Dalton Caldwell is the co-founder of both and imeem. Mr. Caldwell has college degrees in Psychology and Symbolic Systems, both from Stanford University.
Steve Huffman Steve Huffman is the co-founder of Hipmunk from YC S10. Prior to Hipmunk, Steve co-founded the social news site reddit in 2005 with Alexis Ohanian. Reddit, from Y Combinator’s original batch in Summer 2005, has since grown into the largest social news site and one of the largest communities on the Internet.
Justin Kan Justin Kan is an American Internet entrepreneur and investor. He is the co-founder of live video platforms and TwitchTV, as well as the mobile social video application, Socialcam. He also serves as a part-time partner at venture capital firm Y Combinator. His attempt to broadcast his entire life at popularized the term “lifecasting”. His latest startup is Exec, an errand running service that provides companies and individuals access to on-demand personal assistants (for delivery, furniture assembly, research, etc).
Andrew Mason Andrew Mason is the co-founder and former CEO of Groupon.
Michael Seibel Michael Seibel is the CEO of Socialcam. Socialcam was acquired by Autodesk in 2012. Prior to Socialcam, Michael Seibel was the co-founder and CEO of As CEO of, Mr. Seibel oversaw strategy, investor relations, business development and monetization.
Emmett Shear Emmett Shear is an Internet entrepreneur and investor. He is the co-founder of live video platforms and TwitchTV. He’s also a part-time partner at Y Combinator. Mr. Shear co-founded of Kiko Software, the first AJAX-based online calendar. Emmett Shear graduated from Yale University in 2005 with a degree in computer science.
Harjeet Taggar Harjeet Taggar was a founder of Auctomatic, which Y Combinator funded in winter 2007, and which went on to be acquired by Live Current Media in 2008. Harj is officially in charge of biz dev at Y Combinator, but he also does pretty much everything the other investors do, including selecting and advising startups. According to Paul Graham, he’s exactly what Y Combinator looks for in a founder: smart, determined, but also a genuinely nice guy.
Garry Tan Garry Tan is a Venture Partner at Y Combinator, previously Designer-in-Residence. Before that, Garry Tan was a cofounder at Posterous, cofounded the financial analysis platform at Palantir Technologies, and was a Program Manager at Microsoft for Windows Mobile. Mr. Tan graduated from Stanford in Computer Systems Engineering in 2003.


Partners That Advise On Technical Matters

Name Description
Trevor Blackwell AnybotsTrevor Blackwell is a computer programmer, engineer and entrepreneur based in Silicon Valley. Dr. Blackwell is a developer of humanoid robots. He is also the inventor of the Eunicycle, essentially a one-wheeled Segway. Dr. Blackwell is the founder and CEO of Anybots and a partner at Y Combinator. Dr. Blackwell grew up in Canada. Dr. Blackwell studied engineering at Carleton University and received a BEng in 1992, then studied Computer Science at Harvard University and received a PhD in 1998. His dissertation applied randomized methods to analyzing the performance of networks and compilers. During graduate school, Dr. Blackwell joined Viaweb for which he wrote the image rendering, order processing, and statistics software. The company was acquired by Yahoo in 1998, and Dr. Blackwell moved to Silicon Valley to lead the Yahoo Store development group. He founded Anybots in 2001 to build teleoperated humanoid robots. In 2006 Anybots announced a humanoid robot that walks and balances like people do, without depending on large feet for stability. As side projects, he has built two other balancing vehicles: a two-wheeled balancing scooter similar to the Segway but with different steering, and the self-balancing Eunicycle. Several hobbyists have built vehicles based on the open design of the machine. Together with Paul Graham, Robert T. Morris and Jessica Livingston he founded Y Combinator in 2005.
Robert T. Morris Robert T. Morris is an American professor at Massachusetts Institute of Technology, in the department of Electrical Engineering and Computer Science. He is best known for creating the Morris Worm in 1988, considered the first computer worm on the Internet. He also co-founded the online store Viaweb, one of the first web-based applications, with Paul Graham. He is the son of Robert Morris, the former chief scientist at the National Computer Security Center, a division of the National Security Agency (NSA). Morris created the worm while he was a graduate student at Cornell University. The original intent, according to him, was to gauge the size of the Internet. He released the worm from MIT to conceal the fact that it actually originated from Cornell. The worm was designed to count how many machines were connected to the internet. The worm spread rapidly, infecting several thousand computers. It was estimated that the cost of “potential loss in productivity” caused by the worm at each system ranged from $20,000 to more than $530,000. The worm exploited several vulnerabilities to gain entry to targeted systems, including a hole in the debug mode of the Unix sendmail program, a buffer overrun hole in the fingerd network service, the transitive trust enabled by people setting up rexec/rsh network logins without password requirements. Robert Morris served no jail time but was sentenced to community service, probation, and a fine of $10,000, even though federal sentencing guidelines in such cases called for much harsher consequences.
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