Nuclear energy startup Deep Fission is once again attempting to enter the public markets, renewing investor focus on one of the more unconventional reactor companies targeting the fast-growing AI data center sector.
The company announced plans for a new Nasdaq IPO aimed at raising approximately $157 million, a move that would value the startup at as much as $1.66 billion. However, the announcement has raised significant questions because Deep Fission had already claimed to have gone public less than a year ago through a reverse merger transaction.
Back in September 2025, Deep Fission revealed it had completed a reverse merger with Surfside Acquisition, a Delaware shell company, while simultaneously raising $30 million through a private placement priced at $3 per share. At the time, the company described the transaction as effectively taking the startup public.
But according to newly filed regulatory documents, the company’s shares never actually traded on any public market. Deep Fission reportedly intended to list on OTCQB, a marketplace designed for smaller developing companies that do not meet the stricter listing requirements of exchanges such as Nasdaq or the New York Stock Exchange. However, no public trading activity ever materialized, and the company itself acknowledged in its latest filing that its stock had never been publicly traded.
Now Deep Fission is pursuing a more traditional IPO route through Nasdaq, seeking a dramatically higher valuation than before despite continuing operational and financial challenges.
The proposed offering comes at a notable moment for the nuclear sector, particularly as investor enthusiasm around AI infrastructure and energy demand continues to accelerate. Companies developing nuclear technologies have increasingly promoted their reactors as potential long-term power solutions for massive AI data centers that require stable electricity generation.
Deep Fission’s concept centers around placing nuclear reactors deep underground inside vertical boreholes. The company argues that subterranean deployment could improve safety and reduce infrastructure requirements compared to traditional above-ground nuclear facilities.
However, despite the ambitious vision, the company’s latest SEC filing paints a difficult picture regarding its current progress.
According to the filing, Deep Fission’s timeline for activating its first reactor has slipped beyond earlier expectations. In previous disclosures made in late 2025, the startup stated it hoped to achieve nuclear criticality — the stage where a reactor sustains a controlled chain reaction — by July 2026. In the latest filing, however, the company no longer provides a projected timeline for reaching that milestone.
The filing instead places heavier emphasis on the company’s drilling operations, suggesting that engineering and geological challenges may be more difficult than originally anticipated.
Deep Fission said it began drilling the first of three planned test wells in March. The current well is expected to gather geological and technical data from depths reaching approximately 6,000 feet underground. Yet the existing test well is only eight inches in diameter, far smaller than the boreholes required for commercial deployment.
At full scale, the company expects it will eventually need boreholes measuring between 30 and 50 inches wide and extending roughly a mile underground. Those dimensions would exceed the size of many boreholes commonly used in the oil and gas industry, highlighting the significant engineering complexity involved.
The company also admitted that it has not yet finalized the exact dimensions needed for commercial reactors because it still does not know how large of a borehole it can realistically drill at scale. That uncertainty directly impacts reactor design and future deployment plans.
Financially, the startup’s position appears increasingly strained.
Deep Fission’s accumulated deficit reportedly widened from $56.2 million to $88.1 million over recent months. Its cash reserves also declined sharply, with the company reporting a $6.4 million reduction in cash and equivalents within roughly six weeks — a drop of around 7%.
Most importantly, the latest filing continues to include a “going concern” warning, meaning auditors believe there is substantial doubt about the company’s ability to continue operating if additional funding is not secured. Deep Fission stated that without successfully completing the IPO, it may not have enough capital to sustain operations over the next year.
The situation has created confusion among some observers because the company’s financial and technical outlook appears weaker now than it did during earlier fundraising efforts, despite pursuing a far larger valuation.
One major development since late 2025 is an $80 million equity investment round that included participation from data center developer Blue Owl. Blue Owl also reportedly signed a non-binding memorandum of understanding tied to potential future power plant projects.
Still, even that investment was not enough to eliminate the company’s going concern warning.
The broader market backdrop may partially explain Deep Fission’s renewed IPO attempt. Investor enthusiasm around nuclear fission startups has intensified in recent months, particularly after nuclear company X-energy successfully completed an upsized IPO earlier this year.
However, analysts have noted that X-energy is significantly further along commercially and regulatorily than Deep Fission. X-energy is already generating revenue and has advanced much deeper into the Nuclear Regulatory Commission licensing process, giving it a far more mature operational profile.
That contrast has led to growing debate about whether investor excitement around nuclear-powered AI infrastructure is inflating valuations for earlier-stage companies that remain years away from commercial deployment.
For now, Deep Fission appears to be betting that strong market appetite for AI-related energy solutions will outweigh investor concerns about technical uncertainty, delayed milestones, and ongoing financial losses.
As enthusiasm surrounding nuclear energy and artificial intelligence continues to grow, the company’s upcoming IPO may become an important test of how much risk investors are willing to tolerate in pursuit of next-generation power technologies.
