News Release
Kyoto Fusioneering Secures JPY 25.72 Billion to Build the Systems Every Fusion Power Plant Will Need
The first close of the Series D brings JPY 16.72 billion in new equity and access to JPY 9.0 billion in credit and loan facilities, roughly doubling the company’s equity base. The funds accelerate UNITY™ — integrated demonstrations of the tritium fuel cycle and the tritium breeding blanket across Japan, Canada and the United States — and scale gyrotron manufacturing to meet demand from fusion programs worldwide.
TOKYO — 24 August 2026 — Kyoto Fusioneering (KF) today announced the first close of its Series D round, securing JPY 16.72 billion (approx. USD 105 million) in new equity along with access to JPY 9.0 billion (approx. USD 57 million) in credit and loan facilities, for JPY 25.72 billion (approx. USD 162 million) in total. The funds will accelerate the UNITY™ Program, KF’s staged de-risking program spanning Japan, Canada, and the United States, and expand the company’s supply capacity and international operations.
KF’s business is not the fusion reaction itself. It is everything surrounding the reaction to make fusion a commercial power source: the systems that heat the fuel, absorb the energy the reaction throws off, convert that energy into useful forms, and generate and recycle the fuel. Most of the fusion industry is working on the reaction. KF works on the plant that must be built around it, regardless of fusion approach.
Three Countries, One De-Risking Program
KF is addressing two of fusion’s hardest gating risks — the “tritium fuel cycle” and “tritium breeding blanket and thermal cycle” — through separate-effects testing at purpose-built facilities, ahead of full-scale integration. No other program in the world is attempting this at the same scale.
At UNITY-1 in Kyoto, construction of the power-generation test plant is largely complete. The facility puts a blanket mockup through the temperatures, pressures and magnetic fields representative of a real plant, and converts the heat it produces into electricity and other high value forms. KF is currently running tests that extract hydrogen isotopes from the circulating loop — the same process that will later recover bred tritium — and from this fall will run integrated tests of power generation and hydrogen production from the high-temperature loop.
At UNITY-2, developed with Canadian Nuclear Laboratories through the Fusion Fuel Cycles Inc. joint venture, a fuel cycle systems are in preliminary testing in Japan using hydrogen and other gases. Tritium-based testing at Chalk River is set to begin within the year, targeting the world’s first demonstration of a continuous, fully integrated D-T fuel cycle using real tritium: injecting fuel, recovering what is not consumed, purifying it and putting it back, without stopping.
At UNITY-3 in Tennessee, developed with Oak Ridge National Laboratory and the U.S. Department of Energy, a module-scale neutron irradiation facility for the tritium breeding blanket is in design, targeting facility completion by the end of 2028. It is designed to be the world’s first demonstration of tritium breeding performance under volumetric D-T fusion neutrons.
Once all three are running, KF will be the first company in the world to have tested systems essential for commercial fusion power. This round will go primarily toward accelerating that work.
An Industry Enabler: The Infrastructure Every Fusion Plant Needs
Fusion developers worldwide are pursuing various confinement approaches — from magnetic to inertial confinement devices and everything in between — each differing in how they confine and heat fusion fuel to the point where it fuses. Whichever approaches ultimately reach commercial power generation, they will need the same systems outside the reaction itself. KF builds those systems for the industry as a whole rather than for any one design.
This is why fusion programs around the world already run on KF’s gyrotrons — the high-power microwave tubes that help heat fusion fuel to the temperatures at which it reacts, well over a hundred million degrees. Building on foundational technology developed by Japanese research institutions, KF has pushed gyrotron performance to a world-leading level and paired it with the supply-chain management and precision final assembly needed to deliver products tailored to each project’s specifications. That combination of technical strength and delivery reliability has won KF a steady stream of orders from public and private fusion programs worldwide.
As demand grows, KF will use this funding to build mass-production capacity and a supply system that can respond quickly — putting the industrial base in place before fusion plants start being built, rather than after.
A Five-Country Footprint
KF operates in five countries — Japan (Tokyo; Kyoto; Shiga), the United States (Oak Ridge; Seattle), the United Kingdom (Culham), Germany (Karlsruhe), and Canada (Ottawa; Chalk River) — having raised over JPY 32 billion in cumulative equity funding to date and over JPY 14 billion (approx. USD 88 million) in enterprise-wide life-to-date sales.
The Series D investor group spans policy institutions supporting decarbonization and green transformation (GX), major infrastructure operators, government-affiliated financial institutions, and global and crossover investors. That range reflects fusion energy’s growing recognition as a target for cross-border industrial investment. Proceeds will fund the UNITY™ Program, gyrotron mass-production capacity, and KF’s engineering and commercial operations across its five markets.
Funding Overview
- Series D equity raised (first close): JPY 16.72 billion (approx. USD 105 million)
- Cumulative equity raised to date: JPY 32.98 billion (approx. USD 207 million)
- Total credit and loan facilities secured: JPY 9.0 billion (approx. USD 57 million)
* USD figures are provided for reference only and are approximate, based on a JPY/USD exchange rate of approximately 159 as of August 23, 2026.
■ Select* New Equity Investors
- IMM Japan Korea-Japan Fusion Fund Investment Limited Partnership (General Partner: IMM Investment Japan Co., Ltd.)
- SiteGround Capital Ltd.
- GX Acceleration Agency (Organization for the Promotion of Transition to a Decarbonized Growth-Oriented Economic Structure)
- Development Bank of Japan Inc.
- East Japan Railway Company (JR East)
- Minerva Growth Partners, Inc.
*List does not include two additional new investors
■ Existing Equity Investors, Follow-on Investment
- SMBC Venture Capital Co., Ltd.
- Kyoto Capital Partners Co., Ltd.
- JIC Venture Growth Investments Co., Ltd.
- Daiwa Corporate Investment Co., Ltd.
- DBJ Capital Co., Ltd.
- MUFG Bank, Ltd.
■ Select* Debt Financing / Credit Facility Providers
- Sumitomo Mitsui Banking Corporation
- The Kyoto Bank, Ltd.
- Sumitomo Mitsui Trust Bank, Limited
- Mizuho Bank, Ltd.
* List does not include one additional institution
Comment from Representative Director & CEO Satoshi Konishi
We are deeply grateful – not just for the scale of this round, but for the range of investors who joined it.
We see it as confidence in KF, and as a sign that fusion energy is moving from research into industrialization. We also take it as recognition of our evolution into a company that, regardless of reactor concept, provides, in an integrated manner, the technologies essential to fusion power demonstration projects worldwide.
Since our founding, we have been committed to establishing the core technologies and engineering essential to power generation. With this funding, we will further accelerate that journey.
In the long-term challenge of commercializing fusion energy, we will continue working together with partners around the world to build the fusion energy industry.
Investor Comments (New Investors)
IMM Japan Korea-Japan Fusion Fund Investment Limited Partnership
(General Partner: IMM Investment Japan Co., Ltd.)
Chief Investment Officer, Harutaka Imaizumi, and Bumki Kim, Principal
We are truly proud to have had the opportunity to participate in this funding round for Kyoto Fusioneering — a global leader in the industrialization and commercialization of fusion energy — through the Korea-Japan Fusion Fund that we manage. We are deeply grateful that IMM Investment was chosen as a partner supporting the innovative value and future potential of this leading-edge deep-tech company from Japan, and for the opportunity Kyoto Fusioneering has given us. We will do our utmost to help ensure that this collaboration becomes a pioneering model of success that drives the development and social implementation of advanced technology through close Japan-Korea cooperation.
SiteGround Capital Ltd.
Managing Partner, Tenko Nikolov
At SiteGround Capital, we have deep conviction that fusion is no longer a question of whether but of who builds the infrastructure to make it real. Kyoto Fusioneering stood out to us precisely because they identified the hardest engineering problems in fusion: blanket systems, fuel cycles, plasma heating, years before they became industry consensus, and have been executing against them with remarkable discipline ever since. Clean energy and fusion sit at the very heart of our investment thesis, and we are genuinely bullish about where this industry is heading. It is a true honour to support Kyoto Fusioneering on this journey, and we look forward to being a committed partner as they move from demonstration to commercial delivery.
GX Acceleration Agency
COO (Executive Managing Director), Naoki Shigetake
Fusion is a revolutionary next-generation energy source that contributes to both decarbonization and energy security. Kyoto Fusioneering possesses world-class technology and momentum in developing the core equipment and systems that contribute to its realization, among other areas, and already plays a solid role in global fusion research through partnerships with public research institutions and companies in Japan and abroad. Through this investment, we hope to support the Company’s challenge and expect it to steadily lead efforts toward the global implementation of fusion.
Development Bank of Japan Inc.
General Manager, Corporate Finance Department V, Koichi Kinouchi
Fusion energy is drawing growing expectations worldwide as a next-generation energy source that can contribute to both decarbonization and energy security.
We regard Kyoto Fusioneering as a leading Japanese company that possesses the core technologies essential to power generation — plasma heating, fuel cycle, and tritium breeding blanket and thermal cycle systems — and is powerfully advancing the commercialization of fusion energy, with engineering capability to integrate these technologies as its core strength. Through extensive collaboration with research institutions and companies in Japan and abroad, the Company is also building the industrial foundation needed for the future realization of fusion plants, beyond technology development alone, and we recognize its great potential to lead the creation of a Japan-origin fusion industry.
Through this investment, DBJ will support the Company’s challenge from a long-term perspective, while contributing to the social implementation and industrialization of fusion energy and to the strengthening of Japan’s industrial competitiveness.
East Japan Railway Company (JR East)
Managing Executive Officer, Yoshihisa Nishimura
Under our Group Management Vision “To the Next Stage” 2034, JR East is advancing its business around two pillars — Mobility and Lifestyle Solutions — as we work to achieve a people-focused Lifestyle Transformation (LX). Within that effort, reconciling stable energy supply with decarbonization is an extremely important management challenge.
Fusion energy is one of the next-generation technologies Japan should focus on — one that not only addresses this challenge but also contributes to realizing a hydrogen-based society.
On this occasion, we made this investment out of our shared conviction in the strong technical capabilities and future potential of Kyoto Fusioneering, which is leading the development of core technologies essential to commercialization — including plasma heating systems, fuel cycle systems, and thermal cycle systems. Through this investment, we will help advance the practical application of fusion energy and contribute to realizing LX in Japanese society.
Minerva Growth Partners, Inc.
Kensuke Murashima (Founding Partner) and Taisei Hirakawa (Senior Associate)
Against the backdrop of dramatic advances in AI, growing energy security concerns, and decarbonization, Minerva believes fusion energy will form a major new market over the coming decades. Within that market, Kyoto Fusioneering has built an exceptionally unique position as the “picks and shovels” supporting fusion players worldwide.
We at Minerva are delighted to have had the opportunity to invest at this stage in the ultra-long-term vision of the team led by CEO Konishi, and we will do everything we can to support the Company’s challenge of growing into an infrastructure company underpinning the global fusion industry.
Investor Comments (Existing Investors, Follow-on)
SMBC Venture Capital Co., Ltd.
President & Representative Director, Naoki Kanbayashi
Since our previous investment in 2023, fusion energy research and development has advanced significantly, and we have become convinced that Kyoto Fusioneering is an indispensable presence in the world. We made this follow-on investment with high expectations that the Company will powerfully lead the upcoming demonstration and social implementation phases. Fusion energy is expected not only to solve a range of current energy challenges but also to create a massive market said to be worth tens of trillions of yen. We will continue to support the Company as it pursues this ambitious challenge toward realizing that future.
Kyoto Capital Partners Co., Ltd.
Director, Venture Investment Division, Yasuhiro Suzumura
Against the backdrop of rising electricity demand driven by the spread of AI, the emergence of geopolitical risk, and the demand for a decarbonized society, momentum is growing to seek new energy sources. As competition in fusion development is expected to accelerate further, we made this additional investment in the belief that Kyoto Fusioneering is an indispensable presence in the fusion industry. As part of Kyoto Financial Group, we will do our utmost to support the Company’s challenge of realizing fusion energy.
JIC Venture Growth Investments Co., Ltd.
Venture Capitalist, Yuki Kuwabara
Fusion energy is an important technology field from the standpoint of future energy security and industrial competitiveness. Kyoto Fusioneering is one of the few companies leading the development and commercialization of the core technologies required for fusion plants, and it has established a strong international presence. Through this additional investment, we will support the Company’s further growth and contribute to strengthening the industrial foundation needed for Japan to demonstrate competitiveness in the fusion industry.
Daiwa Corporate Investment Co., Ltd.
Shinichi Seto, President & CEO / Sho Sengoku, Senior Deputy Manager
About five years have passed since our first investment in the Series B round. During that time, the global energy landscape has grown increasingly complex, and how to reconcile the transition to clean energy with securing energy security has become an ever more important challenge. Research institutions and companies around the world are competing fiercely in technology demonstration toward realizing fusion energy while actively pursuing fundraising, and in Japan too, we sense growing expectation and interest in fusion, led by the formulation of a sector-specific national strategy. Against this backdrop, we feel deeply honored to participate in financing that enables Kyoto Fusioneering’s outstanding technology and talent to help co-create the world’s future.
DBJ Capital Co., Ltd.
President & Representative Director, Susumu Kurabayashi
We are deeply honored to have had the opportunity to make an additional investment in Kyoto Fusioneering’s Series D funding round.
Fusion energy is drawing particular attention within Japan’s growth strategy, valued not only for its promise as a next-generation energy source but also from the standpoint of economic security. We expect Kyoto Fusioneering to play an indispensable role in achieving future commercialization, and as a venture capital firm within the Development Bank of Japan (DBJ) Group, DBJ Capital will continue to do everything we can to support the Company’s further growth and the early social implementation of fusion energy.
MUFG Bank, Ltd.
Managing Executive Officer, Head of Solution Division, Ryuichi Ishikawa
As reactor development accelerates around the world toward the social implementation of fusion energy, Kyoto Fusioneering is a Japan-born startup that develops advanced technologies supporting the realization of fusion plants and operates globally. The technologies and equipment the Company develops draw on the excellent technology and know-how of many Japanese companies. We believe the Company’s growth will translate the strengths of Japanese manufacturing into competitiveness in the emerging field of fusion.
Through this funding round, we expect technology development through partnerships with organizations in Japan and abroad to progress further, the Company’s business foundation to be strengthened, and this to lead to the early social implementation of fusion energy and the formation of a new industry in Japan.
Under our purpose, “Committed to empowering a brighter future,” MUFG will continue to contribute to a sustainable society by supporting initiatives that help resolve environmental and social challenges.
About Kyoto Fusioneering
Kyoto Fusioneering is the world’s premier fusion technology and integrated systems developer. It delivers plasma heating, tritium fuel cycle, and tritium breeding blanket and thermal cycle systems that advanced fusion programs worldwide depend on, regardless of confinement approach. KF operates globally across Japan, the United States, the United Kingdom, Germany, and Canada. Visit us at kyotofusioneering.com.
