Y Combinator Tracks 454 Repeat Founders as Second-Timers Claim Growing Share of Early-Stage Capital

Quick Facts

• Y Combinator’s dataset covers 454 repeat founders across 935 founder-company records from 2005 through 2026, with participation peaking at 65 repeat founders in 2025.
• Repeat founders captured more than 50% of all Seed and Series A capital in 2025, per Carta data, and accounted for 40% of total round volume.
• The average gap between YC appearances is 5.1 years, though nearly 30% of returns happened within two years of the prior batch.

Y Combinator has published its first systematic count of founders who have gone through the accelerator more than once. The dataset, provided directly by YC to Crunchbase News, covers 454 repeat founders and 935 founder-company records spanning the program’s earliest 2005 cohorts through 2026.

Of those 454 founders, 428 went through YC exactly twice. Twenty-five appeared three times. Twitch and Stash co-founder Justin Kan is the only four-time participant on record.

The raw count of repeat founders peaked in 2025 at 65. YC moved to four batches per year beginning in fall 2024, which expands the eligible alumni pool faster than prior years.

What Separates Second-Timers

Aaron Epstein, a general partner at YC and co-founder of Creative Market, which he sold to Autodesk in 2014, has worked with more than 1,000 startups at the accelerator. The companies he has backed carry a combined value of roughly $57 billion.

Epstein says the edge repeat founders hold is practical, not abstract. “They know exactly how to get the most out of the advice, network and resources available to them,” he said. “The biggest mistake I see second-time founders avoid is overhiring or overspending pre-product-market fit.”

He also pointed to AI tooling as a force multiplier for experienced operators. Repeat founders using AI, he said, “actually become the people that can produce at 10x or 100x what a traditional engineer would be able to.”

A Founder’s Second Act

Sherwood Callaway went through YC’s fully remote Summer 2021 batch with Opkit, a healthcare fintech startup focused on insurance verification. He describes it as “not the right thing for me to be working on, but a really fun and interesting and rewarding first venture.”

When Callaway returned for his second company, Sazabi, he deferred his batch to build out more product first. “I wanted to use YC as a go-to-market acceleration event,” he said, a move he credited directly to having gone through the program before.

In late June, Sazabi announced an $8 million seed round led by J2 Ventures, Village Global, and Y Combinator, with participation from more than 60 angels including operators from Vercel, Cursor, and OpenAI. Callaway described the company’s focus as rebuilding software observability for teams that include AI agents.

Callaway drew a direct comparison between current market conditions and the 2021 funding environment. “Spring 2026 felt similar to fall 2021, 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,” he said.

Capital Follows the Track Record

The investment numbers reinforce what YC’s dataset shows anecdotally. Carta data from September 2025 shows more than 50% of all Seed and Series A capital that year went to founders who had previously led a venture-backed company. Repeat founders also accounted for 40% of total round volume, meaning their deals were not just more frequent but larger.

Several complete founding teams returned to YC together for second companies, including the teams behind Layer by Layer, Voodoo Manufacturing, Ultra, Blair, and Fastgen.

By 2026, AI coding tools write an estimated 41% of all code, with 84% of developers using AI in some form. For a founder with a decade of domain experience and a small team, that productivity gain compounds in ways it does not for a generalist managing a large headcount.

For investors evaluating early-stage deals, a second-time YC founder now carries a specific credentialing stack: prior YC participation, venture-backed experience, and a willingness to return to a structured program. That combination has proven statistically predictive enough that it is reshaping where early-stage capital goes.

Read more: The Return Of The Repeat Founder: Inside YC’s Growing Class Of Second-Timers