HISTORICAL P100 / #62

Helion Energy

Fusion Energy · United States

Historical ranking valuation$5.40BSource snapshot: Jun 19, 2026

Disclosed primary funding in this record

$1.4B

Sum of non-overlapping disclosed USD amounts in confirmed primary financing entries in this record, including separately labeled equity components; not verified lifetime funding. Excludes amounts already included in a later round, announced, reported, database-only, debt, secondary and unclassified events.

3 confirmed primary rounds with disclosed USD amounts · Record through 2026-09-24

THE BUSINESS

Get to know Helion Energy.

Helion develops fusion-energy machines and a planned power plant. Its website describes Polaris as a development machine and Orion as a plant under construction; it does not establish that commercial grid power has already been delivered.

Helion fusion technology overview ↗Source checked Sep 24, 2026

Valuation history

Valuations reported at the time of each round.

Sep 2026$15.5B post-moneySeries G (final close) · ConfirmedSource ↗

Jun 4, 2026$15.5B post-moneySeries G (initial announcement) · AnnouncedSource ↗

Jan 28, 2025$5.425B post-moneySeries F · ConfirmedSource ↗

Funding history

Funding rounds, debt and other financing events.

5sourced events · record as of 2026-09-24

Helion's Series G closed at $500M in September 2026, including the initial $465M June announcement; these are not additive. Its 2021 Series E closed at $500M, while a further $1.7B was milestone-contingent opportunity, not closed capital. A database's 2023 $100M Series D label conflicts with the 2021 Series E sequence and lacks corroboration, so it is not counted as primary. The 2014 $1.5M is contemporaneously reported, not issuer-confirmed. Confirmed capital is a subset, not a lifetime total.

Sep 2026LATEST SOURCED

primary

Series G (final close)

Thrive Capital (lead) · Alta Park Capital · Anti Fund · BoxGroup · Lux Capital · Peak XV Partners · Bill Ford · Capricorn Technology Impact Funds · +4 more

Amount$500M totalValuation$15.5B post-money

Jun 4, 202604

primary

Series G (initial announcement)

Thrive Capital (lead)

Included in September 2026 $500M Series G final close; not added again to the confirmed-raised sum.

Amount$465MValuation$15.5B post-money

Jan 28, 202503

primary

Series F

Lightspeed Venture Partners · SoftBank Vision Fund 2 · Sam Altman · Mithril Capital · Capricorn Investment Group · Good Ventures Foundation · Nucor

Amount$425MValuation$5.425B post-money

Nov 5, 202102

primary

Series E

Sam Altman (lead) · Dustin Moskovitz · Mithril Capital · Capricorn Investment Group

Amount$500M closed; additional $1.7B milestone-contingent opportunValuationUndisclosed

Aug 14, 201401

primary

Series A (contemporaneous report)

Y Combinator · Mithril Capital Management

Amount$1.5MValuationUndisclosed

Unverified database leads (1)

These database claims have not been independently verified and are excluded from the sourced-event count.

Apr 2023UNVERIFIED

other

Unverified $100M database entry (Series D label conflicts)

Investor participation not independently verified

Amount$100M database claimValuationUndisclosed

Financing participants

Investors, lenders and other parties named in funding announcements.

Thrive Capital

Series G (final close) · Sep 2026 · Lead participant · primary · Confirmed · Confirmed source ↗

Series G (initial announcement) · Jun 4, 2026 · Lead participant · primary · Announced · Announced source ↗