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Miresso

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Low-cost beryllium refining for fusion energy

Tokyo, JapanFounded 2023Energy
Valuation $0–100M Latest valuation · 2026
Headcount <100 Current team size
Total funding $10–50M Disclosed equity funding
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About Miresso

Miresso is a Japanese startup, established in May 2023, that is focused on enabling the commercialization of fusion energy through a stable, low-cost supply of beryllium. The company was founded by CEO Masaru Nakamichi, who leveraged his research from the National Institutes for Quantum Science and Technology (QST), where he was the group leader of the Functional Materials Development Group. His background is in fusion blanket engineering, and he holds a Ph.D. in Engineering from Tohoku University. Co-founder Suguru Nakano, the Director of Technology Development, also worked with Nakamichi at QST on beryllium research and development.

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The company's core technology is a patented low-temperature refining process for beryllium, a critical neutron multiplier material needed for fuel self-sufficiency in fusion reactors. Traditional beryllium refining requires high temperatures over 2,000°C, making it expensive and energy-intensive, which creates a significant bottleneck for the fusion industry. Miresso's process uses a combination of chemical processing and microwave heating to dissolve beryllium ore at under 300°C and at normal atmospheric pressure, aiming to drastically reduce costs and energy consumption. This technology addresses the predicted shortage of beryllium, as a single fusion prototype reactor is estimated to require more than the current annual global production.

Miresso's primary business involves the manufacturing and sale of beryllium. To scale up its technology, the company is building a pilot plant named "BETA" (Beryllium Testing Plant in Aomori) with a target completion for full-scale production in fiscal year 2027. The plant is expected to produce 1-2 tons of beryllium annually, supplying both the emerging fusion industry and existing markets in aerospace, medical imaging, and electronics. A commercial mass production plant with a 100-ton annual capacity is planned for 2031. The company's business model also includes a technology platform, offering R&D, consulting, and licensing of its low-temperature refining process for other mineral resources like rare earths and lithium, as well as for recycling applications.

Source: Dealroom company data

At a glance

Status
Operational
Founded
2023
Headquarters
Tokyo, Japan
Employees
7
Open positions
None listed
Dealroom signal
59.1/100
Industry
Energy, Chemicals
Sub-industry
Clean Energy
Sector
Energy, Spinout, Sustainable Development Goals, Nuclear Fusion, Advanced Materials, Climate Tech, Rare Earth
Technology
Deep Tech
Business model
Manufacturing
Client focus
b2b

Latest news

Press, funding announcements and product moves mentioning Miresso.

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Funding history

4 recorded events

Company financing events and reported valuations.

Deal typeDateAmountValuationInvestorsSource
SERIES AEquity / VC Feb 2026 $18M $74M Mitsubishi UFJ Capital · NTT DOCOMO Ventures · SBI Investment · Mitsui
SERIES AEquity / VC Aug 2025 $14M $56M Genesia Ventures · Pacific Metals · Spiral Capital
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Growth signals

Miresso website traffic

Latest recorded traffic for Miresso is 1.5K monthly website visits, down 46.4% over the last three months.

Latest monthly visits1.5K 3-month web change-46.4%
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Similar companies

Closest operating peers by Dealroom taxonomy

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Investors

15 investors on the cap table

From Dealroom's funding and investor records, grouped by the round each investor first entered.

Seed1 investor entered at this stage

  • Global Brain Corporation

Series A12 investors entered at this stage

  • Spiral Capital
  • Genesia Ventures
  • Pacific Metals
  • SBI Investment
  • Mitsubishi UFJ Capital
  • NTT DOCOMO Ventures
  • Mitsui
  • Itochu Technology Ventures
  • MPower Partners
  • Alconix Ventures Corporation
  • Kyoto Capital Partners
  • Keio Innovation Initiative

Other known investors2 additional known investors

  • National Institutes for Quantum Science and Technology
  • Mitsui Sumitomo Insurance Venture Capital
Team profiled 1 named & role-tagged
Founders Hidden — book a demo/100 quality score
Key operators 1 quality Hidden — book a demo/100
Potential founders Hidden — book a demo likely future founders
Startup mafia Hidden — book a demo alumni-founded startups
Talent movements Hidden — book a demo in · Hidden — book a demo out past 12 months

Source: Dealroom Talent Intelligence.

Global footprint

Workforce and web traffic by country
Workforce by country
1 countries with
team presence
🇯🇵 Japan100%
1 country shown

Market sentiment

Posts on X, past 7 days

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Source: X recent search ranked by engagement (likes + retweets) · Synthesis by Claude · Cached for 1 hour

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