1 Reason Nuscale Power and Oklo Investors Should Be Extremely Nervous in 2026

Small modular reactor (SMR) stocks have soared in value in recent years. Since the start of 2024, for example, NuScale Power (NYSE: SMR) has surged in value by more than 400%. Competitor Oklo Inc (NYSE: OKLO) has seen its stock price rise by nearly 600% over the same time period.

At one point in 2025, however, both stocks were up more than 1,000% since the start of 2024. Why the big pullback? The viability of each company's nuclear technology still seems like a reasonable bet to me over the long term. But right now, the market seems focused on each company's ability to execute its sales pipelines.

Moving the technology from design to regulatory approval is hard enough. Now, SMR firms like Oklo and NuScale are being forced to validate their sales and execution strategy. As we'll see, there are some legitimate reasons to be worried about these efforts in 2026.

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Pipeline concerns should scare Oklo and NuScale investors

In 2024, research from the Institute for Energy Economics & Financial Analysis warned SMR investors against near-term optimism. "Small modular reactors still look to be too expensive, too slow to build, and too risky to play a significant role in transitioning from fossil fuels in the coming 10-15 years," the research concluded.

It's not that SMR technology isn't promising. It is. Over the long term, small modular reactors will likely play a key role in transitioning the global economy away from oil and gas. Instead, this research simply concluded that the timelines involved wouldn't match what bullish investors want to believe.

"A key argument from SMR proponents is that the new reactors will be economically competitive," adds a co-author of the report. "But the on-the-ground experience with the initial SMRs that have been built or that are currently under construction shows that this simply is not true."

In 2025, the market generally ignored this cautionary report. Shares of Oklo and NuScale Power surged by 200% to 300% last year off the backs of new partnership contracts and customer acquisitions. In 2026, shares of Oklo and Nuscale are both now down nearly 20%. Why? Uncertainty regarding how quickly these contracts will turn into real revenues.

Once planned for a 2030 deployment, for example, Nuscale's keystone project in Romania is now targeting a 2033 start date. Some analysts downgraded the stock, citing growing execution and capital risks. Oklo's project pipeline has also come under sharp scrutiny, especially following massive stock sales by the company's CEO and CFO in December, January, and February. These stock sales totaled well over $100 million.

Are SMR stocks still a long-term buy?

Despite the recent correction, shares of both Nuscale Power and Oklo remain relatively high versus the recent past. Oklo stock, for example, is still up roughly 180% since the start of 2025. Yet their total market caps remain very reasonable for businesses that could eventually upend the global energy paradigm. Oklo's market cap is just $10 billion, while Nuscale's valuation is hovering just above $4 billion.

These low market caps reflect two stark realities. First, there is no guarantee that these technologies will ever be deployed by customers at scale. Proving the economics of a real-world deployment is likely still years away. And until that happens, real-world demand will remain muted. Second, both Oklo and Nuscale will need to raise significantly more capital to not only survive, but deliver on any contractual obligations. That means significantly more share dilution at fairly low valuations.

I'm still very bullish on SMR technology for the long term. But any potential investment thesis will need to rely on a holding period of a decade or more. Unless you're willing to dollar-cost average over a very long holding period, it's likely better to view these stocks as lottery tickets with extremely opaque futures.

Ryan Vanzo has no position in any of the stocks mentioned. The Motley Fool recommends NuScale Power. The Motley Fool has a disclosure policy.