Signs of strain emerge in the fusion energy funding boom

In every emerging industry, there comes a point when founders and investors begin with a shared long-term vision, only for that alignment to shift as funding increases and expectations evolve.

That dynamic is becoming evident in the fusion energy sector, which I observed firsthand at Fusion Fest London 2026, hosted by The Economist last week. While the overall atmosphere remained optimistic—supported by roughly $1.6 billion in fundraising among fusion startups over the past 12 months—clear divisions were emerging over two key issues: the timing of public listings and whether startups should pursue side businesses.

The question of going public dominated discussions throughout the event. Over the past four months, both TAE Technologies and General Fusion have moved toward becoming publicly traded through merger-based structures. These deals could unlock hundreds of millions of dollars in additional capital, while also giving long-term investors—some of whom have stayed invested for nearly two decades—an opportunity to exit.

However, not all investors and industry observers agree with the timing. Many expressed concern that these companies are heading into public markets too early, before reaching key scientific milestones that are widely considered essential benchmarks for progress in fusion development.

To recap, TAE Technologies announced in December that it would merge with Trump Media & Technology Group. Although the deal is still pending, TAE has already received approximately $200 million of a potential $300 million tied to the transaction, providing funding to continue its reactor development efforts. The remaining funds are expected to be available after the company files its S-4 registration with the U.S. Securities and Exchange Commission.

General Fusion, meanwhile, announced in January that it would go public via a reverse merger with a special purpose acquisition company. The deal is expected to raise around $335 million and value the combined entity at approximately $1 billion.

Both companies have a strong incentive to secure additional funding. Before its merger announcement, General Fusion faced financial pressure, including layoffs affecting 25% of its workforce. Its CEO, Greg Twinney, publicly appealed for investment support during that period. The company later received a $22 million funding injection in August. Still, industry observers note that such capital is quickly consumed in fusion research due to the high cost of equipment, experiments, and staffing.

TAE Technologies, while in a comparatively stronger position, has also required substantial capital. The company has raised nearly $2 billion over its nearly 30-year history. However, its pre-merger valuation stood at around $2 billion, according to PitchBook, meaning investors were largely breaking even rather than seeing significant returns.

Neither TAE nor General Fusion has yet achieved scientific breakeven—a milestone where a fusion reaction produces more energy than is required to initiate it. Many experts believe other privately held fusion companies may reach this milestone first. One industry executive noted that without achieving scientific breakeven soon, companies could face difficult scrutiny during future earnings cycles if they become publicly listed.

There is also concern that if either company underperforms after going public, it could negatively impact investor sentiment across the broader fusion sector.

Despite these risks, TAE Technologies has begun exploring additional revenue streams, including power electronics and radiation-based cancer therapies. These initiatives could generate near-term income while the company continues long-term reactor development. General Fusion, however, has not yet announced similar diversification strategies.

This reflects a broader divide in the industry over whether fusion companies should pursue commercial revenue early or remain fully focused on achieving a functional power plant.

Some firms are actively embracing parallel revenue strategies. Companies such as Commonwealth Fusion Systems and Tokamak Energy have announced plans to commercialise technologies, including advanced magnets. Others, including TAE Technologies and Shine Technologies, are pursuing applications in nuclear medicine.

In contrast, some startups argue that diversifying too early could dilute focus. One example is Inertia Enterprises, which has emphasised maintaining strict focus on developing a working fusion power plant. This concern is echoed by some investors who worry that profitable side ventures could divert attention from core technical milestones.

There is also no consensus on when fusion companies should go public. Proposed benchmarks include scientific breakeven, facility breakeven—where a reactor produces more energy than the site consumes—and commercial viability, where output is sufficient to supply energy to the grid at scale.

One potential milestone that could shift the industry is expected progress from Commonwealth Fusion Systems, which is targeting scientific breakeven as early as next year. Some industry observers believe that achieving this milestone could also catalyse a public listing.

For now, the fusion sector remains buoyed by funding but increasingly divided over how and when to transition from long-term research to commercial execution.