Nuclear stocks tied to artificial intelligence energy demands suffered a sharp selloff on August 18, driven not by company-specific news but by growing doubts about whether AI companies can sustain their massive power infrastructure spending. Oklo and NuScale each dropped roughly 6%, while Constellation Energy fell about 4%, as investors reassessed the durability of AI-driven nuclear investment.

The trigger was Anthropic's announcement that its annualized revenue run rate reached $65 billion at the end of July, a figure that fell short of the $80 billion many Silicon Valley investors had expected. The company also guided potential IPO investors toward 2028 revenue projections of $190 billion to $200 billion, well below the $400 billion to $500 billion exit valuations some analysts had cited.

What made this revenue miss particularly damaging to nuclear stocks was a Wall Street Journal analysis showing that nine major technology companies carry roughly $3 trillion in off-balance-sheet commitments tied largely to artificial intelligence. These forward-looking obligations, which include long-term power purchase agreements with nuclear developers, are growing faster than traditional capital expenditures of roughly $600 billion over the past year.

Why Did Interest Rates Make the Selloff Worse?

The market downturn was amplified by rising interest rates, which hit nuclear developers particularly hard. The 30-year Treasury bond reached a 19-year high at 5.31%, while the 10-year climbed to 4.68%. For pre-revenue nuclear companies like Oklo and NuScale, higher discount rates directly reduce the net present value of their long-duration, capital-intensive projects.

Nuclear power plants require enormous upfront investments that take years to generate returns. When the cost of borrowing money increases, the financial math becomes significantly less attractive for investors evaluating whether to fund these projects. This is why the sector's most speculative players, which have no current revenue, were hit harder than Constellation Energy, which operates an existing fleet of nuclear reactors and generates real cash flow.

How Do These Three Companies Actually Differ?

The market's reaction revealed a critical distinction between nuclear players that the broader investment community had been treating as a monolithic group. Constellation Energy, despite its 4% decline, operates from a position of fundamental strength. In the second quarter, the company delivered adjusted earnings per share of $2.55 versus the $2.33 consensus estimate on revenue of $7.5 billion. Management raised full-year 2026 adjusted earnings guidance to $11.50 to $12.50 per share.

Oklo and NuScale, by contrast, remain entirely pre-revenue bets with commercial power generation still years away. Their stock prices are derivatives of hyperscaler capital expenditure trends, not reflections of operating performance or cash generation. This distinction explains why the market treated them as AI infrastructure plays rather than as traditional utility stocks.

"Demand for additional compute, and by extension, additional power, has not slowed from hyperscaler customers," said Joe Dominguez, CEO of Constellation Energy.

Joe Dominguez, CEO at Constellation Energy

Dominguez noted that projected 2026 spending was "nearly 75% higher than last year and continue to be revised upward," suggesting that at least for operating nuclear fleets, the AI power demand story remains intact.

Dominguez

What's the Broader Context for These Stock Declines?

The August 18 selloff interrupted what had been a recovery within a broader rally. Over the previous month, Oklo had gained about 7%, Constellation roughly 10%, and NuScale around 19%. However, year-to-date performance tells a much grimmer story. Oklo is down 39%, Constellation down 21%, and NuScale down 35%. Most striking, NuScale has plummeted roughly 74% over the past year, reflecting the extreme volatility and risk premium attached to pre-revenue nuclear developers.

The technology sector was the worst-performing group on the day, while utilities, healthcare, consumer defensive, and energy stocks traded higher. Yet the AI-linked nuclear names fell despite the energy sector's strength, underscoring that investors are pricing these companies as leveraged bets on AI capex durability rather than as traditional power generators.

How Should Investors Think About Nuclear Stocks Going Forward?

• Revenue Reality Check: Pre-revenue nuclear developers like Oklo and NuScale are entirely dependent on whether AI companies follow through on multi-year power purchase agreements. Any sign that AI spending is slowing or being reassessed triggers immediate valuation pressure.
• Interest Rate Sensitivity: Nuclear projects are among the most capital-intensive, longest-duration investments in the energy sector. Rising interest rates directly reduce the present value of future cash flows, making these investments less attractive to both developers and their financiers.
• Operating Versus Speculative: Constellation Energy's more resilient performance reflects its status as an operating utility with real earnings, cash flow, and the ability to raise rates. Pre-revenue nuclear plays offer no such cushion and are entirely dependent on execution and market sentiment.

The August 18 selloff exposed a fundamental tension in the AI-nuclear narrative. While hyperscaler demand for power remains robust, investors are now questioning whether the magnitude and durability of that demand justifies the capital commitments companies have made. For nuclear developers, the question is no longer whether AI needs power, but whether AI companies will actually pay the prices and timelines necessary to make nuclear projects economically viable.