Startup accelerator Y Combinator has long had a reputation for spotting exceptional first-time founders before anyone else. Lately, a different kind of founder has been showing up in greater numbers: one who has already participated in the highly selective program at least once.
To dig into this trend, Crunchbase News analyzed a dataset of repeat founders who have gone through YC’s cohorts. That analysis revealed some very interesting insights. The dataset, shared with us directly from YC, consisted of 454 repeat founders through the program as well as 935 founder-company records spanning 2005 through 2026.
What we found is that repeat participation to date has mostly been a two-chapter journey: 428 founders (94%) went through YC exactly twice, while only 25 appeared three times. Twitch and Stash co-founder Justin Kan was the sole four-time founder.
Other highlights: Founders typically returned to YC five years after their previous appearance, with an average gap of 5.1 years. However, the data reveals two distinct themes. Nearly 30% of return participations occurred within two years — including 38 in the same calendar year — while 61 returns happened after a decade or more. Some founders jump straight into their next venture, while others take years off to build experience before coming back around.
Repeat founder numbers peak in the most recent data, hitting 65 in 2025. But that doesn’t automatically mean people are returning at higher rates. In recent years, YC cohorts have grown significantly, and the 2025-26 numbers include newer batch formats alongside potentially incomplete data.
It’s also clear that returning to YC isn’t always a solo journey.
Several complete founding teams returned together for subsequent companies, including those behind Layer by Layer, Voodoo Manufacturing and Ultra, as well as Blair and Fastgen.
A trend YC partners are watching closely
Aaron Epstein, a general partner at the San Francisco-based accelerator who worked the spring 2026 batch, has enjoyed a front-row seat to the shift. In that cohort, he said he had “a bunch of repeat, second-time founders” he’d worked with before — several during their previous YC company.
“It definitely feels like more of a trend now,” Epstein said. Still, he’s careful not to overstate the novelty.
“It’s not a new thing. But the alumni base of past YC founders continues to grow,” he said in an interview with Crunchbase News, and that naturally translates into more people eligible to come back.
Epstein has worked with more than 1,000 startups at YC. Before that, he was a startup entrepreneur himself, co-founding Creative Market (YC W10), a marketplace for graphic design assets that he sold to Autodesk in 2014 before spinning it back out as an independent company in 2017.
Ask him what separates second-time founders from first-timers, and he points to experience using the program itself.
“They know exactly how to get the most out of the advice, network and resources available to them,” he said. “Having been through the startup grind, they get really good at focusing on the signal that matters and cutting out the noise.”
That experience also helps them avoid a specific, costly mistake.
“The biggest mistake I see second-time founders avoid is overhiring or overspending pre-product-market fit,” Epstein said. “The biggest regret of all the successful first-time founders I know is that they hired too many people, moved way slower and didn’t like working at their own companies anymore.”
Leaner teams, powered by AI
That instinct toward leanness shows up in another pattern: Many repeat founders are choosing to start solo the second time around.
“Some of them (repeat participants) are solo founders, but they’re not building alone,” Epstein said. “They already have networks of people they can bring in as founding employees. This helps them move faster, and feels more fun and less lonely.”
He compares this shift to how cloud computing eliminated the need for startups to raise large sums just to pay for servers.
“It wouldn’t surprise me if 10-15 years from now you look back at all the money startups had to raise to hire people and realize that’s not a requirement,” he said.
AI is accelerating that shift, and Epstein sees it pulling former company builders, including himself and YC CEO Garry Tan, back into hands-on product work.
“It’s so easy to get back into it and start building again. And it’s incredibly exciting,” he said. That mix of hard-won product sense and new tooling, he believes, is changing what one person can build alone.
“They actually become the people that can produce at 10x or 100x what a traditional engineer would be able to build,” he said.
As an example, Epstein pointed to Farza Majeed, a founder he first worked with on buildspace in 2020 who’s now building HeyClicky, an AI tool that helps founders manage their projects and automate tasks.
Even so, Epstein believes founders keep coming back for the same core reasons: personalized advice from partners, a community of ambitious peers, access to top investors and alumni, and the urgency of the batch environment.
“The pressure cooker environment of the batch, which pushes them to move even faster, and distribution to thousands of companies within the network,” he said. “It’s extremely hard to replicate those things on your own.”
From Opkit to Sazabi
One of the repeat founders Epstein has worked with is Sherwood Callaway, whom YC has now backed twice.
Callaway’s path to Silicon Valley began almost by accident. As a college sophomore, he skipped a lined-up investment banking internship after reading about a software bootcamp in San Francisco — a decision he calls “probably the single most important” of his life.
From then on, his goal was clear: “I wanted to do my own venture-backed tech startup, and I wanted to do a YC venture-backed tech startup.”
After gaining experience at Crunchbase and fintech Brex, he founded his first company, Opkit, in YC’s fully-remote summer 2021 batch. Opkit was a healthcare-fintech startup building insurance verification and revenue-cycle-management software.
“It was, in retrospect, not the right thing for me to be working on, but a really fun and interesting and rewarding first venture,” he said in an interview. Opkit was later acquired by 11x AI.
That experience shaped his second company, Sazabi, a name chosen deliberately in contrast to Opkit.
“Opkit wasn’t very personal to me. It was more of an MBA case study approach to starting a business,” he said. “With Sazabi, it needs to really be in alignment with who I am and my passions and interests.”
Sazabi, an AI-native observability platform competing with incumbents like Datadog, draws directly on work Callaway has done throughout his career — a return, in his words, to “what I know best.” He sees it as part of a common pattern: First-time founders often avoid building in the field they know best, then return to it with their second company.
Callaway hadn’t originally planned to go through YC again, and the reconnection happened almost by chance through an email that looped in his former partner on Opkit, Epstein. Once Callaway decided to return, he was more strategic about timing, even deferring his batch to build out more of the product first.
“I wanted to use YC as a go-to-market acceleration event,” he said, something he likely wouldn’t have known to do without having gone through the program before.
The founder was back at YC in person for the first time this spring. He described the second-time experience as something entirely new: “It was really something special.”
This time around, Callaway also noticed a more experienced cohort than his own first batch, along with new concerns specific to the AI era. “There’s a lot of anxiety around what the durable moat is in an AI world when lines of code are effectively free,” he said.
On fundraising, he drew a pointed comparison to 2021. “Spring 2026 felt similar to fall 2021,” he said, “but unlike 2021, where interest rates and ZIRP drove a lot of that energy, in 2026 it’s driven by AI and by real material gains.”
The company’s thesis is resonating with investors. In late June, Sazabi announced an $8 million seed round led by J2 Ventures, Village Global, and Y Combinator, with participation from Orange Collective and more than 60 angels from companies including Vercel, Cursor and OpenAI.
“AI has changed how software gets written. Now it is changing how software gets operated,” Callaway said. “Sazabi is rebuilding observability from first principles for a world where agents are part of every engineering team.”
Overall, as AI continues to lower technical barriers and YC’s alumni pool keeps growing, second-time founders like Callaway are becoming an increasingly visible part of the accelerator’s lineup.
Illustration: Dom Guzman
