The needs of big tech and the growth of artificial intelligence (AI) are driving a resurgence of nuclear power, as countries scramble to keep up with rising energy demand.
Nano Nuclear Energy (NNE 3.92%) and Constellation Energy (CEG +0.24%) fall within the nuclear-investment spectrum, but they are at far ends of that scale. Nuclear power is already responsible for nearly 20% of the electricity generated in the U.S. and the Trump administration is pushing for more nuclear power.
Let's see which of these two stocks will benefit more from this increased demand and which one is a better buy right now.
How different could Nano and Constellation be?
Nano is a small-cap start-up founded in 2020 and went public via an initial public offering in 2024. It specializes in micro reactors and portable nuclear batteries for remote industrial sites, military bases, and some space applications.
NASDAQ: NNE
Key Data Points
Nano's micro-modular reactors (MMRs) are designed to be significantly easier and less expensive to get up and running than traditional reactors, thanks to their modular assembly and factory-produced components. Its flagship microreactor is the Kronos MMR, which it acquired early last year from Ultra Safe Nuclear Corporation, following that company's bankruptcy.
Nano doesn't have any revenue, though it did improve its cash position to $203.3 million at the end of 2025. Since it had a net loss of $40.1 million in 2025, it has several years before it has to worry about running out of cash.
Constellation is a large-cap stock that has the largest fleet of nuclear reactors in the U.S. It's also diverse, though, as it uses nuclear, natural gas, geothermal, hydro, wind, and solar power to generate 10% of the clean energy in the U.S. The company has been around since it was spun off from Baltimore Gas and Electric in 1999.
NASDAQ: CEG
Key Data Points
Constellation, the largest private-sector energy company in the U.S., delivered revenue of $19.1 billion through the first nine months of 2025, a rise of nearly 7% year over year. Its earnings per share (EPS) were $6.02, a 34% decline compared to the same period a year ago.
Which company has more growth?
Both stocks have struggled over the past year. Nano's shares are down more than 27% over the past year but up more than 595% over the past three years. Constellation's shares have fallen more than 10% over the past year but are up more than 34% over the past three years.
Nano, even without any revenue, has a higher share price ceiling because its market cap is so small. However, that also means its stock is more volatile and could easily drop because it is so speculative. Constellation has a proven track record of revenue and EPS growth, but as a larger company, its shares aren't likely to skyrocket anytime soon.
The better buy: Constellation
Constellation has much more size and diversity. For example, if nuclear energy demand is reduced, Constellation can likely offset the revenue loss from its other energy sources. Constellation has been viewed in the past as a safe, if stodgy, utility, but is now seen as a key partner in the infrastructure tech companies need.
There's a lot to be excited about with Nano, as its niche market is expected to grow. However, it doesn't have a track record as a profitable company, and that's a big leap for many start-ups.
