Rebel Fund
Reviewed Updated May 1, 2026This profile is AI-generated. If you spot an error, please help us fix it by sharing a URL to the correct information.
Team
About
Rebel Fund is a San Francisco–based seed-stage venture capital fund that invests exclusively in Y Combinator alumni startups 1. The fund was founded in 2019 by Jared Heyman, a YC W13 alumnus (CrowdMed), and is staffed by a roster of YC-alumni partners who co-founded companies including Reddit, Instacart, Cruise, Scribd, Rappi, and Optimizely 1.
Rebel pitches itself as a data-driven YC-focused fund, claiming a “nearly 100% deal win rate” pre-Demo Day and the ability to evaluate every YC company using a proprietary machine-learning model called the “Rebel Theorem” 1 2. As of February 2026, Tracxn reported Rebel Fund had invested in 128 companies, with 16 new investments in the trailing 12 months 3. Of those, 52 are seed-stage deals (average round size $4.44M) and 13 are Series A follow-ons (average round size $11.2M) 3.
Stated Thesis
Rebel Fund publicly describes its strategy as investing in “the top 10% of startups (top 0.06% of applicants) from Y Combinator,” using proprietary machine learning to score companies pre–Demo Day 1. The firm targets a diversified seed portfolio across YC’s quarterly batches rather than picking themes.
Founder Jared Heyman has described the underlying approach as follows (Medium, June 2025):
“I often say that technically our algorithm is scoring companies, but really it’s scoring founders.” 4
Inferred Thesis
Counted portfolio: 128 verified investments as of Feb 2026 3.
- Stage: 52 seed (41%), 13 Series A (10%), 1 Series B (<1%); remainder are smaller follow-on or pre-seed checks. The fund is overwhelmingly a seed-stage vehicle 3.
- Pipeline: Exclusively YC alumni. Every check goes into a company that has gone through (or is going through) Y Combinator 1. This is the single most distinctive thesis pattern in the dataset: Rebel does not source outside YC.
- Sectors (per Tracxn aggregation): Enterprise applications, fintech, and “high tech” dominate the portfolio, mirroring the broader composition of recent YC batches rather than reflecting a sector preference imposed by Rebel itself 3.
- Notable unicorns: Jeeves (corporate cards/banking, LatAm) and Airbyte (open-source data integration) 3.
- Exits: 6 acquisitions to date including Payflow 3.
- Check-volume distinctive: Tracxn’s 128-company count over 2019–2026 implies roughly 18–25 new investments per year, considerably higher than a typical seed boutique. This reflects Rebel’s stated strategy of building a “diversified seed portfolio” by writing many small checks across each YC batch 2 3.
Portfolio
| Company | Stage | Year | Lead Partner | Sector | Status |
|---|---|---|---|---|---|
| Jeeves | Seed (YC S20) → growth | 2020 | — | Fintech (LatAm corporate cards) | Active (unicorn) 3 |
| Airbyte | Seed (YC W20) → growth | 2020 | — | Data infrastructure | Active (unicorn) 3 |
| Payflow | Seed | ~2020 | — | Fintech (earned-wage access) | Acquired 3 |
| Starling Medical | Seed | ~2022 | — | Healthtech | Active 6 |
| Serif Health | Seed | ~2022 | — | Healthtech (price transparency) | Active 6 |
| Writesonic | Seed | ~2021 | — | AI writing | Active 6 |
| EARTH AI | Seed | ~2022 | — | Mining / AI | Active 6 |
| Didit | Seed extension ($6M; YC + Rebel + others) | 2026-05-26 | — | Fintech / Identity Verification | Active 5 |
The table above is a representative sample of named investments confirmed in public coverage 6. Rebel does not publish a full portfolio list; the canonical count of 128 companies comes from Tracxn 3.
In Their Own Words
On Rebel Fund’s investment approach (rebelfund.vc):
“Since Rebel Fund invests exclusively in seed-stage Y Combinator startups, the dozens of blog posts I’ve published over the years are largely focused on what separates the future YC unicorns from the rest of the pack.” 1
On the role of the algorithm (Medium, June 19, 2025):
“I often say that technically our algorithm is scoring companies, but really it’s scoring founders.” 4
What Founders Say
No independently sourced founder testimonials about working with Rebel Fund were found after dedicated searching. Founder quotes at YC-batch funding events typically credit lead investors rather than syndicate or batch-aligned funds like Rebel.
Sources
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Rebel Fund — homepage and partner roster, accessed May 2026. https://www.rebelfund.vc/↩↩↩↩↩↩
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“Designing a Diversified Seed Portfolio of YC Startups,” Rebel Fund blog, accessed May 2026. https://www.rebelfund.vc/blog-posts/designing-diversified-seed-portfolio-yc-startups-monte-carlo-irr-benchmarks↩↩
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Rebel Fund — Investor Profile, Tracxn, accessed May 2026. https://tracxn.com/d/venture-capital/rebelfund/__9LKEvRR6aOKp7LrB9ffURxW7s_q4DUE1AX4zKxZnBMY↩↩↩↩↩↩↩↩↩↩↩↩
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Jared Heyman, “On Rebel Theorem 4.0,” Medium, June 19, 2025, accessed May 2026. https://jaredheyman.medium.com/on-rebel-theorem-4-0-55d04b0732e3↩↩
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Axios Pro Rata, “Didit $6M seed funding from YC and others,” May 26, 2026. Accessed May 2026. https://www.axios.com/newsletters/axios-pro-rata — Confirms Rebel Fund participated in Didit’s $6M seed extension on May 26, 2026 alongside Y Combinator and other participants. ↩
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Rebel Fund Portfolio Companies, Crunchbase Hub, accessed May 2026. https://www.crunchbase.com/hub/rebel-fund-portfolio-companies↩↩↩↩↩