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Startup · United States

Last Energy

HQ WashingtonFounded 201951-200 employees

Last Energy is a new nuclear energy solution for customers of any size – rapidly deploying, affordable, clean, baseload power at scale with a full-service delivery model.

StartupDevelopmentMicroreactorsSmall modular reactors
Website
Total raised
$163M
4 rounds
Last round
$100M
Series C · Dec 16, 2025
Systems
1
Capabilities
2

Funding4 rounds · $163M

Equity raised
$163M
Latest
$100MSeries C · Dec 16, 2025
Last valuation
$617MPost-money · Series C · Dec 16, 2025
Cumulative raised$163M
Feb 25, 2020Dec 16, 2025
Valuation over time$617M · Dec 16, 2025
Valuation over timeReported valuation rose from $15.0M (Feb 25, 2020) to $617M (Dec 16, 2025) across 4 valued rounds. All are post-money.
Valuations by round
AnnouncedStageValuationBasis
Feb 25, 2020Seed$15.0MPost-money
Feb 16, 2021Series A$88.1MPost-money
Aug 29, 2024Series B$381MPost-money
Dec 16, 2025Series C$617MPost-money

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.

Systems1

PWR-20

A modular pressurized-water reactor design.

Maturity not rated

Newest unveiled first. Open a system for its milestone timeline, components and sources.

Capabilities2

  • Microreactors
    Developer
    PWR-5 pilot under construction at Texas A&M-RELLIS (DOE PDSA approved May 2026); not yet critical.
    DevelopmentReported
  • Small modular reactors
    Developer
    Company markets the 20 MWe PWR-20 as an SMR; the PWR-5 pilot is described as a microreactor.
    DevelopmentReported

Maturity and TRL describe this organization's work; the field-wide maturity is on each technology's page.

People1

All 1 people →

Sources15

Show all 15 sources and supporting evidence

Profile3

  1. 1
    DatabaseLast Energy - PitchBook company profile

    PitchBook · Supports Organization · employee range, Organization · founded year, Organization · x url

    “employee_range: 51-200 (profile: 75)”
  2. 2
    DatabaseSixth-Domain public startups directory

    Sixth-Domain · Supports Organization · country, Organization · kind

    “{"country": "USA", "hq_iso2": "US", "id": "b12c1fff-2159-4777-a37a-6ce8ae9a5f8b"}”
  3. 3
    DatabaseLast Energy - LinkedIn company profile

    LinkedIn · Supports Organization · employee range, Organization · founded year

    “employee_range: 51-200 (profile: 51-200 employees)”

Systems1

  1. 4
    CompanyTechnology | The PWR-20

    Last Energy · Supports System

    “PWR-20 # Engineered for modular, factory production. Last Energy designs a mass-production pressurized water reactor, utilizing advanced manufacturing technologies to deploy next generation nuclear power at scale.”

Technologies2

  1. 5
    OtherLast Energy, Texas A&M Collaborate to Launch Microreactor Pilot at Texas A&M-RELLIS

    Texas A&M University System · Supports Organization technology

    “This groundbreaking project will deploy Last Energy’s 5-megawatt PWR-5 microreactor — a compact version of its larger commercial design — to demonstrate safe, low-power criticality and, in future phases, electricity generation for the grid.”
  2. 6
    CompanyLast Energy | 20 MWe SMR | Fully modular, factory made

    Last Energy · Supports Organization · description, Organization · linkedin url, Organization · name, Organization · website, Organization technology

    “Last Energy is a new nuclear energy solution for customers of any size – rapidly deploying, affordable, clean, baseload power at scale with a full-service delivery model.”

Funding8

  1. 7
    NewsLast Energy, Inc. announced that it has received $99.999997 million in funding from a group of investors

    MarketScreener · Dec 16, 2025 · Supports Funding round

    “The company has raised $99,999,997 in a round of funding led by new investor Astera Institute”
  2. 8
    NewsLast Energy Raises $100 Million to Build Small Reactor

    Bloomberg · Dec 16, 2025 · Supports Funding round

    “raised $100 million from investors led by Astera Institute”
  3. 9
    CompanyLast Energy Announces Oversubscribed $100 Million Series C

    Last Energy · Dec 16, 2025 · Supports Funding round · amount, Organization · ownership

    “today announced it has closed an oversubscribed Series C of more than $100 million led by the Astera Institute”
  4. 10
    NewsLast Energy Books $40 Million Series B Funding

    Neutron Bytes · Aug 30, 2024 · Supports Funding round, Funding round · amount

    “That round was led by Gigafund”
  5. 11
    NewsLast Energy nabs $40M to realize vision of super-small nuclear reactors

    Canary Media · Aug 29, 2024 · Supports Funding round

    “Venture capital heavyweight Gigafund led the round”
  6. 12
    NewsFunding and commercial agreements grow for Last Energy

    World Nuclear News · Aug 29, 2024 · Supports Funding round · amount

    “US microreactor developer Last Energy announced it has raised USD40 million for its Series B round of funding”
  7. 13
    DatabaseLast Energy - Forge company profile

    Forge Global · Feb 25, 2020 · Supports Funding round · amount, Funding round · post money valuation usd

    “02/25/2020 Series Seed $3M $1.01 $15M First Round Capital, Floodgate”
  8. 14
    DatabaseLast Energy - Crunchbase company profile

    Crunchbase · Feb 25, 2020 · Supports Funding round

    “Seed Round - Last Energy”

People1

  1. 15
    DatabaseLast Energy - Crunchbase company profile

    Crunchbase · Supports Organization · employee range, Organization · hq city, Organization · x url, Role

    “employee_range: 51-200 (profile: 51-100)”

Each fact on this page is attached to the sources that support it. Archived copies are linked when we keep one.