Key Metrics
Recent changes
- Oct 6, 2026Oct 6, 2026Nvidia Backs Reactor, Now At $74M, To Run World Models Pulse story
- Oct 5, 2026Oct 5, 2026Raised an undisclosed amount Fortune
- Oct 5, 2026Oct 5, 2026First reported total funding: $74M Fortune
- Oct 5, 2026Oct 5, 2026New investor: NVentures Fortune
- Oct 5, 2026Oct 5, 2026New investor: Sapphire Ventures Fortune
Earlier changes (2)
- Sep 21, 2026Sep 21, 2026Samsung Puts Up To $100M Into Kairos's Google Reactor Pulse story
- May 26, 2026May 26, 2026Raised $25.2M SEC EDGAR Form D
Funding History
2 events · sources dated per row| Date | Event | Amount | Valuation | Investors | Source |
|---|---|---|---|---|---|
| Oct 5, 2026 | funding round | — | — | NVenturesunverifiedSapphire Venturesunverified | Fortune |
| May 26, 2026 | funding round | $25.2M | — | SEC EDGAR Form D |
Investors
Latest Pulse
- Oct 6, 2026Nvidia Backs Reactor, Now At $74M, To Run World ModelsNvidia's venture arm NVentures invested in Reactor, a startup building cloud infrastructure to run 'world models' faster and cheaper, as the company's total funding reaches $74 million five months after emerging from stealth.→
- Sep 21, 2026Samsung Puts Up To $100M Into Kairos's Google ReactorSamsung C&T agreed to provide up to $100 million in combined equity and engineering support to Kairos Power's 50-megawatt demonstration reactor being built to supply Google with nuclear power by 2030.→
- Jul 27, 2026Antares Raises $470M For Military Nuclear MicroreactorsAntares raised a $470 million Series C -- $370 million equity plus $100 million debt -- co-led by Paradigm and Caffeinated Capital, after achieving initial criticality on its Mark-0 compact nuclear reactor under a DOE pilot program.→
- Jul 27, 2026Antares Nuclear Raises $470M For Military MicroreactorsAntares Nuclear raised a $470 million Series C led by Paradigm and Caffeinated Capital to deploy small nuclear microreactors that can power US military bases independent of the civilian grid by 2028.→
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Reactor FAQ
How much has Reactor raised?
Reactor has raised $74M in total funding (As of Oct 5, 2026, Fortune).
Who are Reactor's investors?
Reactor's investors include NVentures, Sapphire Ventures (As of Oct 5, 2026).
Sources & methodologyshow
Where these figures come from
- SEC EDGAR Form Dprimary source1 fact
- Fortunemajor outlet2 facts
Figures are labelled Reported (a source states it), Estimated, Derived (computed from other facts) or Rumored (in talks / unconfirmed). Rumors never replace a confirmed figure. Each figure keeps its own as-of date; history is preserved rather than overwritten.