Fusion energy startup backed by Sam Altman pursuing direct-electricity-conversion power
Energy📍 Everett, WAFounded 2013
Current Valuation
$5.4B
as of 2024-Q4
UNICORN
IPO Outlookprivate
Is Helion Energy going public?
No. Helion Energy has no imminent IPO plans on record. It is still private.
What is Helion Energy's valuation in 2026?
Helion Energy is valued at $5.4B as of 2024-Q4, set by its Series F ($425M, Jan 2025). That is the last confirmed mark, not a live price — private shares do not trade continuously.
Has Helion Energy filed an S-1?
No public S-1 is on file for Helion Energy.
Who are Helion Energy's investors?
Helion Energy's investors include Sam Altman, Mithril Capital, Capricorn, Dustin Moskovitz, Reid Hoffman, SoftBank.
Answers are derived from the roster record shown on this page — filing status, last round and confirmed marks. Where the record is silent, the answer says so rather than guessing.
Helion is developing a pulsed magneto-inertial fusion reactor that captures electricity directly from expanding plasma without a steam turbine. Signed a 50 MW power purchase agreement with Microsoft, promising delivery by 2028. Sam Altman is the chairman and largest individual investor.
Company Profile
CEO
David Kirtley
Founded
2013
HQ
Everett, WA
Employees
~250
Total Raised
$1.0B
Last Round
Series F — $425M (Jan 2025) · Lead: SoftBank
IPO Status
no imminent plans
Fundraising Status
Series F · $425M · 1y 7mo ago
no imminent plansTotal raised $1.0B
Secondary Market
Implied price / share
$65
Last round price / share
$41.81
vs last round
+55.5%
Last round price vs secondary price
Secondary price return by period
Implied per-share price from private secondary transactions, as of Jun 2026. This is a point estimate, not a quote — the feed carries no bid, ask or spread, and a secondary print is evidence of what someone paid on that date rather than a live market. Compare across every tracked name →
Latest Funding Round
Round
Amount
Date
Lead Investor
Post-Money
Series F
$425M
Jan 2025
SoftBank
—
Talent Signal
Hiring trend
● First snapshot
trend accrues with monthly sweeps
Open roles
108
via ashby
Product-build share
77%
engineering, research, product, design
Trajectory
steady
heavy product build — 77% of open roles are product-building functions (engineering/research/product) — 35 of 108 open roles are hardware.
Actively hiring with no tracked executive churn.
Open roles by month
Open roles by function
■ product-building ■ go-to-market / G&A
R&D Hardware Test & Development ManagerSenior Electrical EngineerSenior Power Electronics EngineerSenior Computational Plasma Scientist - MHDSenior Mechanical Engineer, Plasma DiagnosticsPrincipal Experimental Scientist
Counted from Helion Energy's live job board as of 2026-08-17; role functions classified from posting titles. Open-role counts are an activity signal, not headcount. Refreshed monthly.
Founders & Key People
David KirtleyGeorge VotroubekJohn SloughChris Pihl
Investors
Sam Altman · Mithril Capital · Capricorn · Dustin Moskovitz · Reid Hoffman · SoftBank
Products
Polaris (7th-gen prototype)
Orion (8th-gen, planned for power delivery)
Competitors
Commonwealth Fusion · TAE Technologies · Tokamak Energy
FusionEnergySam AltmanDirect Energy Conversion
Private-company numbers are not real-time. Reflects publicly disclosed valuations from press releases, news reports, and tender offers as of 2024-Q4. Refreshed quarterly.