In short: X-Energy raised $1.02 billion in the largest nuclear IPO on record, pricing at $23 (21% above range) on the Nasdaq, with shares surging 31% on opening to imply a $12 billion market cap. The offering was 15x oversubscribed. The same company failed to close a $1 billion SPAC in 2023. The difference is AI-driven data centre power demand: Amazon committed to 5 GW by 2039, Dow Chemical and Centrica signed on, and the SMR offtake pipeline doubled to 45 GW in 18 months.

In October 2023, X-Energy and Ares Acquisition Corporation mutually terminated a SPAC merger that had valued the nuclear reactor developer at $1.05 billion. The deal collapsed because public market conditions were, in the company's words, “persistently volatile.” Ares liquidated. X-Energy went back to raising private capital. On Thursday, eighteen months later, X-Energy began trading on the Nasdaq under the ticker XE after pricing an upsized initial public offering at $23 per share, 21% above the top of its marketed range. It raised $1.02 billion, the largest nuclear public offering on record. The IPO was 15 times oversubscribed. One-third of institutional orders received zero allocation. Shares opened at $30.11, a 31% pop, and traded as high as $31.33 during the session. The implied market capitalisation exceeded $12 billion. What changed between the failed SPAC and the oversubscribed IPO was not the reactor. The Xe-100 existed in 2023. What changed was that the world discovered it needed the power.

The reactor

The Xe-100 is a Generation IV high-temperature gas-cooled reactor using a pebble-bed design. Each unit produces 80 megawatts of electrical power, cooled by helium gas, fuelled by proprietary TRISO-X particles, tri-structural isotropic coated uranium enriched to below 20%. The fuel is encased in spheres of ceramic and carbon designed not to melt under any postulated condition, retaining more than 99.99% of fission products. The reactor requires no large water supply, no active safety systems, and no emergency diesel generators to prevent fuel damage. It can ramp from 40% to full power in 12 minutes, a load-following capability that makes it suited to pairing with the variable demand profiles of data centres. The design uses four operator-controlled variables. A conventional nuclear plant uses hundreds.

X-Energy's TRISO-X fuel fabrication facility in Oak Ridge, Tennessee, received a 40-year special nuclear material licence from the Nuclear Regulatory Commission, the first new fuel fabrication licence in approximately 50 years and the first for a Category II facility. The construction permit application for X-Energy's flagship project, a four-unit Xe-100 plant at Dow Chemical's Seadrift operations site in Texas, was accepted by the NRC in May 2025, with an 18-month review timeline. The Department of Energy selected X-Energy alongside Bill Gates's TerraPower for its Advanced Reactor Demonstration Programme in 2020, committing approximately $1.2 billion to the Xe-100 and TRISO fuel development. The technology has been in development for over a decade. The capital to commercialise it arrived only when the customers did.

The customers

Amazon led X-Energy's $500 million Series C-1 funding round in October 2024 and signed a binding agreement to purchase up to five gigawatts of nuclear power from the company by 2039. The first project under that agreement is the Cascade Advanced Energy Facility, a four-unit 320-megawatt installation in Washington state developed with the public utility Energy Northwest, expandable to 12 units and 960 megawatts. Amazon's nuclear strategy extends beyond X-Energy: it acquired Talen Energy's data centre campus adjacent to the Susquehanna nuclear plant in Pennsylvania for $650 million and secured a 1,920-megawatt power purchase agreement through 2042. It is exploring a 300-megawatt SMR project with Dominion Energy in Virginia. Amazon needs reliable, carbon-free baseload power for AI data centres that renewables cannot provide around the clock, and rising energy costs are threatening cloud infrastructure globally as geopolitical instability reshapes the economics of electricity.

Dow Chemical's Seadrift project will replace ageing fossil fuel infrastructure with four Xe-100 units supplying both electricity and industrial steam, with Fluor as engineering partner. Centrica signed a six-gigawatt joint development agreement for the United Kingdom's first advanced reactor fleet. X-Energy's total customer pipeline exceeds 11 gigawatts, equivalent to roughly 144 Xe-100 units. The IEA reported this week that AI data centre electricity consumption will triple by 2030 and that the pipeline of conditional offtake agreements between data centre operators and SMR projects has nearly doubled from 25 gigawatts at the end of 2024 to 45 gigawatts today. AI companies are racing to secure data centre capacity, with Mistral alone raising $830 million to build a single 44-megawatt facility near Paris. The power to run those facilities is the constraint. Nuclear is the only carbon-free source that runs at full output regardless of weather, time of day, or season.

The market

X-Energy is the third advanced nuclear company to reach the public markets, after NuScale Power and Oklo. NuScale holds the only NRC design certification for a small modular reactor in the United States but has struggled commercially after the cancellation of its flagship project with Utah Associated Municipal Power Systems. Its stock has been volatile. Oklo, backed by Sam Altman, trades at a market capitalisation of approximately $8.9 billion on revenues that remain minimal, with its stock up 248% over six months on the strength of the AI-nuclear narrative and its Aurora microreactor design. Kairos Power, backed by Google, secured the first NRC construction permit for a Generation IV reactor in December 2023 for its Hermes test facility but remains private. TerraPower, Gates's venture, is building its Natrium sodium-cooled fast reactor with ARDP funding alongside X-Energy but has not announced IPO plans.

X-Energy's $12 billion market capitalisation on its first day of trading reflects neither its current revenue, approximately $163 million, nor its reactor's commercial readiness, which is still years from first power. It reflects the market's assessment that nuclear is no longer a regulatory burden to be tolerated but a strategic asset to be owned. Massive private capital is flowing into nuclear energy across both fission and fusion, with Proxima Fusion seeking two billion euros for a fusion test facility in Germany and record funding pouring into nuclear energy startups across Europe. The World Economic Forum published an article this month titled “This energy crisis is ushering in a global nuclear renaissance,” citing the Strait of Hormuz disruption and AI power demand as twin catalysts. The 15-times oversubscription of X-Energy's IPO is consistent with that thesis. Whether the thesis is correct is a different question.

The gap

The Xe-100 has not produced a watt of commercial electricity. The Seadrift construction permit is under NRC review. The Energy Northwest project is in early development. The Centrica agreement is a framework, not a signed power purchase contract. X-Energy's TRISO-X fuel facility has a licence but is not yet producing fuel at commercial scale. The company's $1.02 billion in IPO proceeds and approximately $1.8 billion raised privately will fund development through the next phase, but advanced nuclear projects routinely experience delays and cost overruns that dwarf initial estimates. NuScale's history is instructive: it received NRC design certification in 2023, lost its anchor customer in the same year, and has spent the time since searching for a replacement. Regulatory approval does not guarantee commercial viability. It only guarantees that the regulatory question has been answered.

The gap between X-Energy's market valuation and its commercial reality is not unique to nuclear. It is the same gap that exists across the AI infrastructure supply chain, from Nvidia's forward-looking multiples to CoreWeave's debt-funded expansion to alternative approaches to powering AI infrastructure that include data centres in orbit. The market is pricing the future demand for AI compute as a near certainty and the supply of energy to run that compute as the binding constraint. X-Energy sits on the supply side of that constraint with a reactor design that has government backing, a fuel licence that took 50 years to issue to anyone, an 11-gigawatt customer pipeline anchored by Amazon, and a share price that assumes all of it will work. The failed SPAC valued the company at $1 billion when nobody needed the power. The IPO valued it at $12 billion because everybody does. The reactor has not changed. The bet is that the need will not change either.