Helion Energy

Helion Energy develops technology to generate electricity through nuclear fusion.

Latest funding

$465M Series B+ · June 4, 2026

Led by Thrive Capital · Source: fundraisingfox.com

Total raised: $1.44B across 6 sourced rounds

All 7 rounds ↓

Website: helionenergy.com.

X: @Helion_Energy · 56,136 followers.

LinkedIn: helion-energy.

Categories: Climate and energy Developer tools and cloud Manufacturing and industrial.

Sectors: Industrials, Energy, Fusion Energy, Hard Tech, Climate.

Stage: Series B+.

Based in: Seattle, United States.

Founded: 2013.

Total raised: $1.44B in 6 sourced rounds.

Last round: Jun 4, 2026 · 161 days ago.

Team: 150 people on the team page.

On Recent Funding since: Sep 28, 2026.

Signals

X account@Helion_Energy · created Nov 19, 2012 (14 years old) · 56,136 followers

Website registeredAug 25, 2008 (18 years old)

About Helion Energy

The company designs, builds, and tests fusion prototypes to advance commercial fusion power systems. Helion aims to deploy fusion-generated electricity to the power grid and has signed customer agreements with Microsoft and Nucor.

TIMELINE · MONEY RAISED

Helion Energy | 620 days from X account to first raise on record

@Helion_Energy·Raised $1442M in 6 sourced rounds·1 signal before the first raise

Money raised, round by round (amounts linked to their source). Pins are dated signals; hover the icons for dates.

Funding rounds

June 4, 2026
Series B+ · $465M · $15.5B valuation
TThrive Capital (lead), AAlta Park Capital, AAnti Fund, BBill Ford, BBoxGroup, CCapricorn Technology Impact Funds, GGood Ventures Foundation, LLightspeed, LLux Capital, MMithril Capital, PPeak XV, SSoftBank Vision Fund 2
Source: fundraisingfox.com
January 28, 2025
Series B+ · $425M · $5.42B valuation
CCapricorn Investment Group, GGood Ventures Foundation, LLightspeed, MMithril Capital, NNucor, SSam Altman, SSoftBank Vision Fund 2
Source: fundraisingfox.com
November 5, 2021
Series B+ · $500M
SSam Altman (lead), CCapricorn Investment Group, DDustin Moskovitz, MMithril Capital
Source: helionenergy.com
September 23, 2020
Series B+ · $40M · $1.25B valuation
DDustin Moskovitz (lead), CCapricorn Investment Group, MMithril Capital, SSam Altman, YY Combinator
Source: helionenergy.com
January 1, 2019
Series B+ · $10M
CCapricorn Investment Group
Source: fusionxinvest.com
August 1, 2014
Seed · $1.5M
MMithril Capital, YY Combinator
Source: nextbigfuture.com
Summer 2014
YY Combinator · batch
Source: ycombinator.com
November 19, 2012
X account created
August 25, 2008
Website created

Founders and team

DK
David Kirtley Founder and CEO

@Dkirtley · LinkedIn · source: foundertrace.com
CP
Chris Pihl Co-Founder & CTO
GV
George Votroubek Co-Founder & Principal Scientist
PJ
Pragav Jain CFO
ST
Savanna Thompson Chief Business Operations Officer

Investors

Companies like Helion Energy

IInertia$450M Series A · Feb 2026
TThe Nuclear Company$51M Series A · May 2025
RRenaissance Fusion$37.62M Series A · Mar 2025
SSmart Fusion Energy$1.68M Seed · Jun 2026
HHonghu Future EnergySeed · Nov 2026
FFocused Energy$240M Series A · May 2026

Other companies backed by Thrive Capital

IImprint$130M Series B+ · Nov 2026
AAbby Care$82M Series B+ · Oct 2026
OOpenEvidence$250M Series B+ · Sep 2026
SSavvy Wealth$100M Series B+ · Sep 2026
RRetro$21M Series A · Aug 2026
AAmbrook$30M Series B+ · Aug 2026

Thrive Capital portfolio →

Sources and API

Every amount links to the page it came from. * Estimated from an accelerator's published standard deal, not a company-specific disclosure. How Recent Funding sources and verifies funding data. The same data as JSON: /api/v1/companies/helion-energy (get a free API key).