Michael Seibel steps back from Y Combinator after more than a decade

Michael Seibel, one of Y Combinator’s longest-serving group partners, has moved into a “partner emeritus” role after more than 12 years with the Silicon Valley accelerator.

Seibel confirmed the transition in a post on X.

A political science graduate and co-founder of both Justin.tv and Socialcam, Seibel has played a central role in guiding YC founders through the early stages of building their companies. Y Combinator says the startups he has advised now hold a combined valuation of $192 billion.

Y Combinator CEO Garry Tan shared the news in a company blog post, highlighting Seibel’s lasting influence on the organisation.

Over 21 YC batches, Seibel conducted 6,500 office hours and advised more than 1,745 companies — a level of involvement that made him one of the accelerator’s most recognisable and trusted mentors.

Tan wrote: “Michael's impact at YC has been massive. He's been instrumental in shaping our programme, our culture, and our values. I know I've learned a ton from him.”

Michael Seibel, one of Y Combinator’s longest-serving group partners, has moved into a “partner emeritus” role after more than 12 years with the Silicon Valley accelerator.

Seibel confirmed the transition in a post on X.

Y Combinator CEO Garry Tan shared the news in a company blog post, highlighting Seibel’s lasting influence on the organisation.

Tan wrote: “Michael's impact at YC has been massive. He's been instrumental in shaping our programme, our culture, and our values. I know I've learned a ton from him.”