Startup · United States
Helion
HQ Everett, WashingtonFounded 2013201-500 employeesUpdated
Develops fusion systems and commercial fusion power plants.
Funding10 rounds · $1.53B
- Equity raised
- $1.53B
- Debt, secondaries & grants
- $5.0M
- Latest
- $500MSeries E+ · Jun 4, 2026
| Announced | Stage | Amount | Valuation | Lead investors | Other investors | Confidence |
|---|---|---|---|---|---|---|
| Jun 4, 2026 | Series E+ | $500M | — | Thrive Capital | — | Confirmed |
| Jan 28, 2025 | Series E+ | $425M | — | — | — | Reported |
| Sep 27, 2023 | Strategic | $35.0M | — | — | — | Reported |
| Nov 5, 2021 | Series E+ | $500M | — | — | — | Reported |
| Sep 23, 2020 | Series D | $40.0M | — | — | — | Reported |
| Jan 1, 2019 | Series C | $10.0M | — | — | — | Reported |
| Jan 1, 2016 | Series B | $21.3M | — | Capricorn Investment Group | — | Reported |
| Oct 1, 2015 | Grant | $5.0M | — | — | — | Reported |
| Jul 6, 2015 | Series A | Undisclosed | — | — | — | Reported |
| Aug 14, 2014 | Seed | $1.5M | — | Mithril Capital Management | — | Reported |
- $500MJun 4, 2026
- Series E+$425MJan 28, 2025
- Strategic$35.0MSep 27, 2023
- Series E+$500MNov 5, 2021
- Series D$40.0MSep 23, 2020
- Series C$10.0MJan 1, 2019
- Series BLed by Capricorn Investment Group$21.3MJan 1, 2016
- Grant$5.0MOct 1, 2015
- Series AUndisclosedJul 6, 2015
- SeedLed by Mithril Capital Management$1.5MAug 14, 2014
Raised counts equity rounds; debt, secondary sales and grants are totaled separately. Amounts in other currencies are converted at the announcement month's average rate. A ~ marks an estimated or converted amount.
Capabilities1
| Technology | Role | Maturity | TRL | Notes | Confidence |
|---|---|---|---|---|---|
| Nuclear energy and propulsion | Developer | — | — | classify_sectors run 37, haiku, taxonomy 2026-10-18b: Develops fusion systems and commercial fusion power plants with no defense use stated. | Reported |
- Developerclassify_sectors run 37, haiku, taxonomy 2026-10-18b: Develops fusion systems and commercial fusion power plants with no defense use stated.—Reported
Maturity and TRL describe this organization's work; the field-wide maturity is on each technology's page.
People6
| Person | Role |
|---|---|
| Chris Pihl | Co-founder |
| David Kirtley | Co-founder |
| George Votroubek | Co-founder |
| John Slough | Co-founder |
| Pragav Jain | CFO |
| Savanna Thompson | Chief Business Operations Officer |
Sources4
Profile1
- 1
Supports Organization · linkedin url
“https://www.linkedin.com/company/helion-energy”
Funding2
- 2
Supports Funding round, Funding round · investors, Organization, Organization · ownership
“Helion closed its oversubscribed Series G at $500M in September 2026, up from an initial close of $465M. The funding was capped despite additional investor interest.”
- 3CompanyHelion | LinkedIn
Supports Funding round, Organization · employee range, Organization · founded year, Organization · hq city, Organization · hq region, Role
“funding round: Series D, 2020-09-23, USD 40,000,000, lead: Dustin Moskovitz”
People1
- 4CompanyHelion | About
Supports Role
“Helion was founded in Washington State by Dr. David Kirtley, Chris Pihl, Dr. John Slough, and Dr. George Votroubek”
Each fact on this page is attached to the sources that support it. Archived copies are linked when we keep one.