TL;DR · 30-second read
The Short Version
Lawmakers are moving a bill that would make large data centers pay the full cost of the power lines and grid upgrades they need, rather than spreading that cost across everyone’s electricity bills.
Shares of small nuclear companies jumped when the bill advanced, then handed the gains straight back. NuScale Power finished down about 7 percent, Oklo about 5 percent and Centrus Energy about 3 percent.
Why it matters: these companies pay for new reactors and fuel plants largely by selling shares. When the share price swings on a vote, so does the money available to build.
Shares of small-reactor and nuclear fuel companies rallied and then reversed around a House bill that would require data centers to cover the power costs their own loads create. According to reporting on the session that followed, NuScale Power fell about 7%, Oklo about 5% and Centrus Energy about 3%, giving back the gains the group had made when the measure advanced.
The move landed in a week in which two of the three companies were actively raising money against their share prices. Oklo disclosed in an 8-K filed September 11 that it had entered an at-the-market equity program of up to $1 billion, and Centrus disclosed in an 8-K filed the same day that it had priced a $500 million offering of stock and warrants on September 9. Centrus followed on September 17 with an 8-K reporting a multi-year high-assay low-enriched uranium supply contract with Antares Nuclear.
Executive Summary
The underlying policy question is narrow and consequential: when a data center of several hundred megawatts connects to the grid, who pays for the transmission upgrades, generation reserves and network reinforcement that load requires — the data center, or the utility’s general ratepayer base? A House bill assigning those costs to the load itself reads, at first glance, as a tailwind for dedicated on-site generation, including small modular reactors, because it raises the cost of taking power from the public grid.
The market tested that logic and then partly withdrew it inside a session. That is worth taking seriously rather than dismissing as noise, because the same rule that makes grid power more expensive also makes the buyers of small-reactor power more expensive to operate — and a bill that has cleared one chamber is not a tariff, a rule or a contract.
What makes the swing operationally relevant is that valuation in this sector is not a scoreboard. It is working capital. Oklo’s $1 billion at-the-market program converts share price directly into build funding, and roughly $2 billion of Centrus’s potential proceeds sits in warrants that only pay out if the stock trades well above where the September offering priced.
Cost Allocation Is the Real Variable Behind AI’s Power Demand
Interconnecting a large load is not simply a matter of running a wire. A multi-hundred-megawatt data center — a megawatt is roughly the steady draw of several hundred homes — typically triggers network upgrades, new substations and reserve capacity that cost hundreds of millions of dollars and take years to build. The question of who pays for that has, until recently, been handled case by case by state regulators and grid operators, often with a meaningful share landing in the rates everyone pays. A federal rule assigning those costs to the load that caused them changes the arithmetic of every site selection decision in the industry.
That is why the initial read was bullish for nuclear developers. If grid-delivered power carries the full loaded cost of the upgrades it requires, plus the multi-year queue wait, then dedicated generation sited at or near the campus stops competing against the cheap headline price of grid power and starts competing against the true all-in cost. Small modular reactors — factory-built units in the tens to few hundreds of megawatts, designed to be sited next to the customer — are positioned precisely for that comparison.
The give-back is the part worth explaining, because it is where the simple version of the thesis breaks. NuScale’s roughly 7% decline, Oklo’s 5% and Centrus’s 3% came without any company-specific bad news attached to them. The plainest reading is that the same rule cuts in two directions at once: it raises the cost of grid supply, but it also raises the total cost of building and operating the data centers that are the presumed offtakers for on-site nuclear. A hyperscaler facing a larger interconnection bill has less budget, not more, and may respond by siting fewer campuses rather than buying more reactors. Whichever way that nets out, the affected parties are the same: data center developers pricing new sites, utilities and their regulators deciding what the general ratepayer absorbs, and the reactor and fuel companies whose demand case is built on the gap between those two answers.
A Bill That Passed One Chamber Is Not a Tariff
There is a second reason a policy rally can evaporate in a session. Legislation of this kind does not usually land as a self-executing rule. Cost responsibility for large loads sits across federal and state jurisdictions, and translating a statutory instruction into actual large-load tariffs, deposit and collateral requirements, minimum-take terms and network upgrade cost assignments is a rulemaking-and-litigation process measured in years — comfortably longer than the development timeline of most of the reactors being valued against it.
None of that makes the bill unimportant. It means the market is pricing a direction of travel, not a set of terms, and direction-of-travel trades are exactly the ones that reverse when the second-order effects get counted. For readers evaluating these companies, the useful discipline is to ask what changed in contracted capacity, licensing position or customer commitments on the day — and in this case, for the reactor developers, nothing did.
When Share Price Is the Construction Budget
Here is where a one-session swing stops being abstract. Pre-revenue nuclear developers and capacity-expanding fuel suppliers fund themselves substantially by issuing equity, which makes the share price an input to the build, not a commentary on it.
Oklo’s 8-K filed September 11 discloses an equity distribution agreement with ten sales agents — Goldman Sachs, BofA Securities, Citigroup, J.P. Morgan, Morgan Stanley, Barclays, Cantor Fitzgerald, Guggenheim, Canaccord Genuity and B. Riley — permitting up to $1 billion of Class A common stock to be sold at the market over time, at a commission of up to 1.5%, off a shelf registration declared effective December 4, 2025. An at-the-market program dispenses stock into the open market at prevailing prices at the company’s discretion; the dollar ceiling is fixed, so the number of shares required to reach it moves inversely with the price. A 5% lower share price means roughly 5% more dilution for the same construction dollar.
Centrus shows the sharper version. Its September 11 filing and the accompanying release disclose an offering priced September 9 at a combined $199.64 per share of Class A common stock and accompanying warrants, comprising 500,000 shares, pre-funded warrants over 2,005,513 shares and common warrants over as many as 6,992,382 shares, for gross proceeds of approximately $500 million. The common warrants come in four series struck at $226.8625, $272.2350, $317.6075 and $362.9800 — between roughly 14% and 82% above the offering price — each series carrying an aggregate exercise price of about $500 million. That is roughly $2 billion of additional funding for domestic enrichment capacity that arrives only if the stock trades and holds well above where it priced, within tranches expiring between the second and fifth anniversaries of September 10, 2026. Policy-driven round trips of 3% to 7% do not decide that outcome on their own, but they are the increments that determine whether a strike price is reached, and they are the reason the grid cost-allocation debate has a direct line to how much enrichment and reactor capacity actually gets financed.
The Part of the Chain That Isn’t Priced on Votes
Centrus’s September 17 8-K and the attached release describe a different kind of event: a definitive multi-year contract to supply Antares Nuclear with high-assay low-enriched uranium — fuel enriched above the level used in conventional reactors, which most advanced designs require — with deliveries commencing before the end of the decade and prepayments from Antares to support expanded capacity. Prepayments are the operative detail. They are customer cash committed ahead of delivery, which is a materially firmer demand signal than a legislative headline.
Two caveats keep this even-handed. First, the release positions the contract around defense and space missions: Antares, founded in 2023 and described as backed by over $600 million in funding, was selected for the U.S. Army’s Janus Program at Fort Bragg, the Air Force’s Advanced Nuclear Power for Installations program at Joint Base San Antonio and a Space Force award, with initial military deployments stated for 2028. It is not evidence of data center demand. Second, the contract’s value, volumes and prepayment amounts are not disclosed, so “adds another HALEU customer to the backlog” cannot yet be sized.
Still, the contrast is the useful takeaway for anyone underwriting this sector. Centrus operates the American Centrifuge Plant at Piketon, Ohio, described in its release as the only licensed HALEU production facility in the western world, and is converting that position into binding orders with cash attached. That is a different asset class from a valuation that moves 3% on a chamber vote — and over time it is the one that determines whether AI-adjacent nuclear capacity gets built.
Background
The three companies sit at different points of the same chain. NuScale Power and Oklo are developers of small modular and advanced reactors, pre-revenue businesses whose value rests on licensing progress and future customer commitments. Centrus Energy is a fuel supplier, operating the American Centrifuge Plant in Piketon, Ohio, which its release describes as the only licensed high-assay low-enriched uranium production facility in the western world; the company says it has supplied more than 1,850 reactor years of fuel since 1998 and launched a multi-billion-dollar enrichment expansion last year.
All three have been repriced repeatedly over the past two years by the same underlying story: data center electricity demand growing faster than grids can be upgraded, and hyperscale operators signing power agreements with nuclear suppliers to secure firm, carbon-free capacity. Because reactor and enrichment capacity takes years and large capital outlays to build, and because these companies fund much of that through equity issuance, policy headlines that move sentiment also move the practical cost of building. Source: Nuclear Stocks Rally as House Bill Forces Data Centers to Cover Their Own Power Costs and NuScale Power Drops 7% as Nuclear Stocks Hand Back the Vote Rally; Oklo Falls 5%, Centrus Energy Slides 3% — coverage of the rally and reversal in small-reactor and nuclear fuel equities around a House bill on data center power cost responsibility. Primary sources: Oklo Inc., Form 8-K filed September 11, 2026 (equity distribution agreement, up to $1 billion at-the-market program); Centrus Energy Corp., Form 8-K filed September 17, 2026 (HALEU supply contract with Antares Nuclear); Centrus Energy, Exhibit 99.1: “Centrus and Antares Sign Multi-Year HALEU Supply Contract,” September 17, 2026; Centrus Energy Corp., Form 8-K filed September 11, 2026 (underwriting agreement, shares and warrants); Centrus Energy, Exhibit 99.1: “Centrus Announces Proposed Public Underwritten Offering of Class A Common Stock and Warrants”; Centrus Energy, Exhibit 99.2: “Centrus Announces Pricing of $500 Million Underwritten Public Offering of Class A Common Stock and Warrants”.Sources