# Helion Energy funding: rounds and investors > Helion Energy has raised $437M across 3 rounds since 2014. Investors include Y Combinator, Mithril Capital Management and Lightspeed Venture Partners. Source: https://millionrounds.com/company/helion-energy (Millionrounds; every figure on the page links to its filing or article) United States · [Series F startup](https://millionrounds.com/companies) # Who invested in *Helion Energy* 3 rounds we have observed, with the 11 investors named in them. Every figure came from a named source, and where the company reported a raise to the SEC itself, that is shown beside it. Cleantech Energy Valuation: $5.4B, Mar 2026 Y Combinator: S14 Follow Helion Energy and see its new rounds in your feed. [Start following](https://millionrounds.com/login?join=1&why=follow&next=%2Fcompany%2Fhelion-energy) Funding summary Updated 15 Nov 2026 **$437M** raised across 3 rounds since 2014, from 5 sources **$1.5M** Seed **$11M** Venture **$425M** Series F - **Latest round:** Series F, $425M Jan 2025 - **Step-up i:** 40× - **Investors:** 11 See who backed them ## The funding story Each circle is a round, placed by date and sized by amount. The line above is the running total. 2014 2016 2018 2020 2022 2024 **$1.5M** Seed **$11M** Venture **$425M** Series F - **First round:** Seed, $1.5M - **Biggest round:** $425M - **Usual gap between rounds:** 9.6 years ## The rounds - **Jan 2025** Series F **$425M** *9 new* *2 returning* [Y Combinator](https://millionrounds.com/fund/y-combinator) [Lightspeed Venture Partners](https://millionrounds.com/fund/lightspeed-venture-partners) [SoftBank](https://millionrounds.com/fund/softbank-2) [SoftBank Vision Fund](https://millionrounds.com/fund/softbank-investment-advisers) [Sam Altman](https://millionrounds.com/fund/sam-altman) [Capricorn Investment](https://millionrounds.com/fund/capricorn-investment-group) [Mithril Capital Management](https://millionrounds.com/fund/mithril-capital-management) [SoftBank Vision Fund 2](https://millionrounds.com/fund/softbank-vision-fund-2) [Dustin Moskovitz](https://millionrounds.com/fund/dustin-moskovitz) [Good Ventures](https://millionrounds.com/fund/good-ventures) [Nucor Corp](https://millionrounds.com/fund/nucor-corp) Reported by Crunchbase News and 2 others - **Jul 2015** Venture **$11M** No investor was named in the report. From a historical funding record SEC filing: $11M sold, first sale Jun 2015 - **Aug 2014** Seed **$1.5M** *2 new* [Y Combinator](https://millionrounds.com/fund/y-combinator) [Mithril Capital Management](https://millionrounds.com/fund/mithril-capital-management) From a historical funding record SEC filing: $1.5M sold, first sale Jul 2014 ## Funding filed with regulators Helion Energy filed 2 raises, $12M in all. Filings say how much was sold and to how many investors; they never name the investors. - Jun 2015 **$11M** 6 investors equity of $21M offered SEC Form D - Jul 2014 **$1.5M** 3 investors equity SEC Form D ## Founders and team From Helion Energy's own website and the SEC filings it signed: 4 founders, 5 on the team. **David Kirtley** Co-founder & CEO *Named on its 2015 Form D* **Chris Pihl** Co-Founder & CTO **George Votroubek** Co-Founder & Chief Scientist **Anthony Pancotti** Co-founder - **Prag Jain** Chief Financial Officer - **Savanna Thompson** Chief Business Operations Officer - **Lynn Miller** General Counsel - **Christopher Pihl** Executive Officer, Director i - **John Slough** Executive Officer, Director i On the board, as filed i *Ajay Royan* *Sam Altman* ## Who was in which round The busiest backers across the latest rounds. A filled square is a round they joined; a dark one, a round they led. **Seed** 2014 **Venture** 2015 **Series F** 2025 [Y Combinator](https://millionrounds.com/fund/y-combinator) [Mithril Capital Management](https://millionrounds.com/fund/mithril-capital-management) [Lightspeed Venture Partners](https://millionrounds.com/fund/lightspeed-venture-partners) [SoftBank](https://millionrounds.com/fund/softbank-2) [SoftBank Vision Fund](https://millionrounds.com/fund/softbank-investment-advisers) [Sam Altman](https://millionrounds.com/fund/sam-altman) [Capricorn Investment](https://millionrounds.com/fund/capricorn-investment-group) [SoftBank Vision Fund 2](https://millionrounds.com/fund/softbank-vision-fund-2) [Dustin Moskovitz](https://millionrounds.com/fund/dustin-moskovitz) [Good Ventures](https://millionrounds.com/fund/good-ventures) ## Everyone who backed them [Y Combinator](https://millionrounds.com/fund/y-combinator) Accelerator **2** rounds [Mithril Capital Management](https://millionrounds.com/fund/mithril-capital-management) VC firm **2** rounds [Lightspeed Venture Partners](https://millionrounds.com/fund/lightspeed-venture-partners) VC firm **1** round [SoftBank](https://millionrounds.com/fund/softbank-2) Investment firm **1** round [SoftBank Vision Fund](https://millionrounds.com/fund/softbank-investment-advisers) VC firm **1** round [Sam Altman](https://millionrounds.com/fund/sam-altman) Angel **1** round [Capricorn Investment](https://millionrounds.com/fund/capricorn-investment-group) Family office **1** round [SoftBank Vision Fund 2](https://millionrounds.com/fund/softbank-vision-fund-2) Growth equity **1** round [Dustin Moskovitz](https://millionrounds.com/fund/dustin-moskovitz) Angel **1** round [Good Ventures](https://millionrounds.com/fund/good-ventures) VC firm **1** round [Nucor Corp](https://millionrounds.com/fund/nucor-corp) Growth equity **1** round Missing a round, or an investor who was in one? [Tell us](https://millionrounds.com/corrections?slug=helion-energy). ## Also claim to have backed them These 2 firms list Helion Energy as a portfolio company on their own websites, but no report of a round names them. They are the firms' own claims, kept apart from the rounds above. [ANTI FUND](https://millionrounds.com/fund/anti-fund) VC firm Per its own site [Unmatched Ventures](https://millionrounds.com/fund/unmatched-ventures) VC firm Per its own site ## Quick answers about Helion Energy ### Who invested in Helion Energy? Helion Energy's investors include Y Combinator, Mithril Capital Management, Lightspeed Venture Partners, SoftBank and SoftBank Vision Fund, and 6 more on record. ### How much has Helion Energy raised? Helion Energy has raised $437M across 3 rounds since 2014. ### When did Helion Energy last raise? Helion Energy's most recent round was a Series F of $425M in Jan 2025. ### What was Helion Energy's biggest round? Its most recent round, $425M in Jan 2025, is also its largest on record. ### Who backed Helion Energy first? Helion Energy's first round on record, in Aug 2014, was backed by Y Combinator and Mithril Capital Management. ### What stage is Helion Energy at? Helion Energy's latest named round is a Series F, in Jan 2025. ### Where is Helion Energy based? Helion Energy is based in the United States. ## Companies like Helion Energy In the same sector, and raised in the last eighteen months. [**Soofa** Nov 2026](https://millionrounds.com/company/soofa)[**New ERA Energy & Digital** $354M · Nov 2026](https://millionrounds.com/company/new-era-energy-and-digital)[**Torus** $739M · Nov 2026](https://millionrounds.com/company/torus)[**Coreshell Technologies** $54M · Nov 2026](https://millionrounds.com/company/coreshell-technologies)[**Atomarine** $20M · Nov 2026](https://millionrounds.com/company/atomarine)[**Reflect Orbital** $94M · Nov 2026](https://millionrounds.com/company/reflect-orbital) ## Find investors like these Search every investor by what they have actually funded, then narrow to your stage and market. Free. Open the investor searchOr these rounds in the app