Japan Inc. & fusion

29 September 2025

Corporate Japan is making a strategic, long-term commitment to fusion

The participation of a consortium of 12 Japanese investors in Commonwealth Fusion Systems‘ $863m Series B2 builds on a steady escalation and broadening of fusion investment activities by corporate Japan. Japanese corporate involvement in fusion has accelerated, moving beyond tentative, small-scale investments to often substantial, strategically significant commitments. Distilled, there has been a shift from an earlier role as passive component suppliers to that of active strategic investors. Japanese corporate and corporate venture capital (CVC) investment has become a notable force both domestically and internationally. 

This is not confined to a single segment but involves a broad front of trading houses, financial institutions, and industrial manufacturers. The investments are characterized by a focus on long-term value creation, ecosystem development, and supply chain dominance, rather than short-term financial returns. In aggregate, such investment forms a significant part of Japan’s emerging and coordinated strategy aimed at securing a leading position in the future global fusion energy market.

Government policy has been instrumental in fostering this investment environment. The Japanese government has provided substantial support for fusion research and development, including direct grants, infrastructure investment, and strategic initiatives such as the “Moonshot Programme.” This public sector commitment, which exceeds $400 million in total, has served to de-risk private investment and validate the commercial potential of fusion technology.

A primary driver is the objective to construct a comprehensive fusion energy ecosystem, the national objective of the “industrialization” of fusion. Encouraged and supported by the government, Japanese corporations are seeking to leverage their advanced manufacturing expertise and long experience in the nuclear sector to build a robust domestic supply chain capable of serving the global fusion market, and to position themselves to capitalize on the significant market opportunities that will arise from the commercial deployment of fusion energy. The benefits of strategic investments – closer relationships, privileged access to knowledge and information, early insights into technologies and operational expertise – can be secured relatively inexpensively especially within the context of the size of many of the investing companies.

Decarbonization and energy security are also important factors. In line with Japan’s national goal of achieving carbon neutrality, corporations view fusion as a viable, long-term solution to the country’s energy challenges. By investing in fusion, these companies are aligning their business strategies with national policy and mitigating the risks associated with a global transition away from fossil fuels.

Broad Engagement

Trading houses (sogo shosha/総合商社) have emerged as particularly active investors, representing a coordinated approach by Japan’s most influential commercial entities. Sumitomo Corporation led with its investment in TAE Technologies and subsequent collaboration with Tokamak Energy, positioning itself to become a leader in fusion power plant financing, construction, and operation. The company’s strategy extends beyond financial returns to encompass the development of comprehensive fusion deployment capabilities across the Asia-Pacific region. Mitsubishi Corporation and Mitsui & Co., Japan’s two largest trading houses, participated in Kyoto Fusioneering‘s landmark Series C round. Mitsubishi Corporation’s investment strategy focuses on building a fusion energy supply chain that leverages Japan’s leading manufacturing capabilities while Mitsui & Co seek to leverage the company’s extensive global client network in energy and adjacent sectors.

Financial institutions have also recognized the strategic value of fusion investment. Mizuho Financial Group’s participation in Zap Energy’s Series D round exemplifies this, with the investment explicitly described as strategic rather than financial, aimed at connecting cutting-edge overseas technologies with Japanese industry to support decarbonization goals. The wider participation of major financial institutions across multiple funding rounds demonstrates mainstream acceptance of fusion investment as a legitimate opportunity, moving fusion investment from early-stage venture capital to more patient, institutional investment.

Industrial companies have also made strategic moves. Furukawa Electric’s evolution from a supplier relationship with Tokamak Energy to a strategic partner with a £10 million equity stake illustrates how Japanese companies are deepening their engagement with fusion technology. The partnership now includes plans for a joint manufacturing base in Japan, demonstrating the commitment to building domestic fusion capabilities.

The emergence of CVC arms as active participants is also evident, notably in the Helical Fusion’s Series A. That round attracted investments from Toyota Gosei, KDDI, and Nikon through their respective CVC operations. This broad participation signals growing confidence in fusion technology among Japan’s corporate establishment and the maturation of Japan’s CVC ecosystem – shepherded by SBI Investment – in supporting deep technology ventures.

National Strategy

The coordinated nature of Japanese corporate investment reflects a systematic evaluation of fusion’s potential impact across multiple sectors of the economy. Rather than opportunistic bets, these investments represent a calculated industrial strategy supported by government policy and aligned with national objectives for energy security and economic competitiveness.

Japan’s national approach differs markedly from its peers and explicitly seeks to co-opt private sector corporations to national objectives. While there are nuances in how the pre-commercialisation phase of fusion advances, overall Japan focuses on strategic industrial positioning, the United States emphasizes high-growth venture capital returns, and the United Kingdom seeks to leverage academic and technical excellence through public-private partnerships.

These three models are not mutually exclusive but complementary, as evidenced by the cross-border investments and partnerships that have and continue to emerge. Japanese corporations are investing in US and UK companies, US venture capital is backing international startups, and UK companies are attracting investors from both Japan and the United States. This interconnected global ecosystem suggests that the ultimate commercialization of fusion energy will likely leverage elements from many approaches: Japan’s manufacturing and supply chain expertise, America’s venture capital and scaling capabilities, and the research excellence and government support of the UK, Germany and others.