Key Highlights

  • X-Energy moved higher on October 6 with no company-specific announcement, part of a broad rally in nuclear-power stocks.
  • Constellation Energy signed a 20-year power purchase agreement with Google covering 3,590 megawatts in total.
  • Smaller nuclear developers including NANO Nuclear, Oklo and NuScale Power all climbed the same day.
  • X-Energy is developing small modular reactors using high-temperature gas-cooled technology, still years from commercial operation.

X-Energy (NASDAQ:XE) moved higher on the Nasdaq Composite on Tuesday, October 6, 2026, as part of a broad rally in nuclear-power stocks. No company-specific announcement from X-Energy was found to explain the move. Instead, the stock traded as part of a sector-wide read-through from the biggest power story of the day.

X-Energy, a recent listing, is developing small modular reactors, a newer class of nuclear plant designed to be built in factory-made sections and installed at a smaller scale than traditional reactors. Its approach uses high-temperature gas-cooled reactors and its own specialized fuel. Like many companies in the advanced-nuclear field, it is still years from widespread commercial operation, so its shares tend to respond strongly to shifts in sentiment about the industry.

The Deal That Moved the Sector

That sentiment shifted sharply on Tuesday. Constellation Energy (NASDAQ:CEG) signed a 20-year power purchase agreement with Alphabet's Google (NASDAQ:GOOGL) covering 3,590 megawatts in total. That includes 890 megawatts of new capacity from upgrades, known as uprates, at 11 reactors in Illinois, Pennsylvania and New Jersey, plus about 2,700 megawatts from existing plants. Constellation plans to invest more than $4.3 billion, with the first uprates due by 2028. It was the company's second major deal with a technology giant in a week, after Amazon (NASDAQ:AMZN) signed for 690 megawatts on September 30.

Constellation's stock rocketed, closing at $300.40.

Nuclear Names Large and Small

The enthusiasm spread quickly. Vistra (NYSE:VST) and Talen Energy (NASDAQ:TLN) soared, and smaller nuclear developers rallied too. NANO Nuclear (NASDAQ:NNE) rose to $16.79, Oklo (NYSE:OKLO) climbed to $38.81 and NuScale Power (NYSE:SMR) reached $8.20 during the session. Lightbridge (NASDAQ:LTBR) and Centrus Energy (NYSE:LEU) also gained, and a uranium-focused exchange-traded fund advanced.

The logic behind the read-through is straightforward. If the largest technology companies are willing to sign 20-year contracts for nuclear power to feed AI data centers, Demand for new reactor designs could grow as well. Investors often extend that reasoning to developers like X-Energy, even though their reactors are not part of the Google deal. Small modular reactors are frequently pitched as a way to place carbon-free power closer to industrial sites and data centers, which helps explain why the group trades together when big-tech power demand is in the headlines.

A Strong Day for the Big Indexes

The rally unfolded alongside record highs. The S&P 500 closed at 7,818.93 and the Nasdaq Composite finished just under 27,600, both records. The Dow added 253 points, while the small-cap Russell 2000 slipped. Utilities were the best-performing sector in the S&P 500, Treasury yields eased and the VIX dipped to around 15.

Development Milestones Will Give X-Energy Its Own Footing

With no company-specific catalyst on Tuesday, X-Energy is likely to keep trading on sector news, including further power agreements between technology companies and generators. Investors will look for updates on X-Energy's own development milestones, regulatory progress and customer agreements, which would give the stock a footing independent of the sector mood.