Vistra vs. Constellation vs. Oklo: Which Nuclear Stock Wins the AI Power Boom?

The AI infrastructure boom has a power problem. Training large language models and running inference at scale requires massive amounts of electricity: and the grid can't keep up. That's why hyperscalers like Meta $META ( ▼ 1.9% ), Microsoft $MSFT ( ▼ 2.15% ), and Amazon $AMZN ( ▼ 1.39% )  are racing to lock down nuclear capacity through long-term contracts. For investors, that's created a new category of AI infrastructure stocks that don't build chips or run data centers: they generate the clean, reliable baseload power that makes AI possible.

Three names dominate the conversation: Vistra $VST ( ▲ 0.35% ), Constellation Energy $CEG ( ▲ 2.11% ), and Oklo $OKLO ( ▼ 4.66% ). All three are nuclear energy stocks, but they're fundamentally different businesses with wildly different risk profiles. Vistra owns operating plants already feeding AI demand. Constellation controls the largest nuclear fleet in the U.S. and is signing hyperscaler contracts at a steady clip. Oklo stock, meanwhile, represents a bet on advanced small modular reactors (SMRs) that don't exist yet: high upside, high execution risk.

The question isn't which is "best." It's which one fits your portfolio and risk tolerance. Here's how to think about each.

The Business Model Breakdown

Vistra operates in the power generation and retail electricity business. The company owns a diversified fleet that includes nuclear, natural gas, and renewables, with nuclear plants in Ohio and Pennsylvania that are now central to its AI power story. Vistra makes money by selling electricity into wholesale markets and through long-term contracts with large buyers. The nuclear assets provide stable, low-cost baseload generation with high capacity factors, which translates into predictable cash flow.

Constellation Energy is the largest owner of nuclear generation capacity in the United States. It spun out of Exelon in 2022 and inherited a fleet of reactors that produce more carbon-free electricity than any other company. Constellation's business model revolves around selling that power through a mix of wholesale market sales and bilateral contracts with commercial and industrial customers: increasingly, that means hyperscalers looking for 24/7 clean energy to run data centers. It's a pure-play nuclear operator with minimal fossil fuel exposure.

Oklo is a development-stage company building advanced fission reactors designed for small-scale deployment. Unlike traditional gigawatt-scale plants, Oklo's reactors are meant to be manufactured in a factory, shipped to site, and deployed in modular configurations. The company doesn't generate revenue from operating plants yet: it's pre-revenue and focused on securing regulatory approvals, building prototypes, and signing offtake agreements. Oklo makes money, eventually, by selling power from reactors it owns and operates under long-term contracts. The timeline is uncertain, and so is the execution.

How Each Taps Into AI Data Center Demand

Vistra's nuclear exposure to AI is immediate and contractual. Meta signed a deal to purchase over 2.1 gigawatts of energy from Vistra's existing nuclear plants in Ohio and Pennsylvania, plus an additional 433 megawatts from planned uprates expected in the early 2030s. These are 20-year agreements, which means Vistra locks in revenue visibility and insulates itself from spot market volatility. The plants are already running, the electrons are already flowing, and the counterparty is one of the most creditworthy companies on the planet.

Constellation Energy has signed multiple long-term contracts with hyperscalers, though details on specific offtake agreements are less public than Vistra's Meta deal. What matters is that Constellation owns the largest fleet, which gives it the scale and flexibility to meet large, sustained demand from AI data centers. The company has also been vocal about the economics of these contracts: long-term, fixed-price agreements that allow it to capture a premium over wholesale power prices in exchange for reliability and carbon-free attributes.

Oklo's AI exposure is entirely forward-looking. Meta's agreement supports up to 1.2 gigawatts of entirely new advanced nuclear capacity in Ohio, with potential availability as early as 2030. That's a big "if." Oklo still needs to finalize its reactor design, secure NRC licensing, build out manufacturing capacity, and deliver on construction timelines. If it works, the upside is transformative: Oklo becomes a scaled operator of next-generation reactors powering AI infrastructure. If it doesn't, Oklo stock remains a speculative bet on technology that may take years longer to commercialize.

Earnings Quality and Cash Flow

Vistra generates real cash flow from operating assets. The nuclear fleet produces stable earnings with high capacity factors, and the Meta contracts layer in long-term revenue visibility. The company is profitable, pays a dividend, and has a track record of managing capital allocation across its diversified generation portfolio. Earnings quality is solid: cash conversion is strong, and the business model isn't dependent on speculative upside.

Constellation Energy also delivers high-quality earnings. The nuclear fleet operates at industry-leading capacity factors, and the company benefits from contracted revenue that reduces exposure to volatile wholesale power prices. Constellation has returned capital to shareholders through dividends and buybacks, and it trades at a valuation that reflects its status as an established operator. The cash flows are tangible, the operations are proven, and the balance sheet supports growth.

Oklo has no earnings. It's pre-revenue, cash-burning, and entirely dependent on future execution. That doesn't make it uninvestable: it makes it early-stage. The risk is that timelines slip, costs overrun, or regulatory approvals take longer than expected. The reward is that if Oklo successfully commercializes its technology, it could capture a large share of the AI power market with a differentiated, scalable product.

Balance Sheet and Capital Return

Vistra maintains a solid balance sheet with manageable leverage and a diversified asset base that supports cash generation across market conditions. The company has returned capital through dividends and share buybacks, and it's in a position to fund plant uprates and capacity expansions without taking on excessive debt. The Meta contracts add to financial stability by locking in long-term cash flows.

Constellation Energy operates with a strong balance sheet, supported by the scale and reliability of its nuclear fleet. The company pays a dividend and has executed buybacks, signaling confidence in its ability to generate free cash flow. Constellation's capital allocation strategy balances reinvestment in plant operations and capacity uprates with shareholder returns.

Oklo's balance sheet reflects its development stage. The company has raised capital through equity financings and SPAC proceeds, but it's burning cash to fund reactor development, regulatory filings, and early-stage operations. There's no dividend, no buyback, and no near-term expectation of positive free cash flow. The balance sheet is a runway: how long it lasts depends on execution speed and capital efficiency.

Key Risks to Watch

Vistra's risks center on regulatory and market exposure. Nuclear plants operate under strict regulatory oversight, and any safety incidents or compliance issues could impact operations. The company also has exposure to natural gas and wholesale power markets, which introduces commodity price risk. The Meta contracts reduce volatility, but they don't eliminate it.

Constellation Energy faces similar regulatory and operational risks inherent to running nuclear plants. The company is also exposed to shifts in energy policy, carbon pricing, and wholesale electricity markets. While long-term contracts with hyperscalers provide revenue stability, Constellation's valuation assumes continued demand for carbon-free baseload power: a bet on the durability of AI infrastructure growth.

Oklo stock carries execution risk, regulatory risk, and technology risk. The NRC licensing process is unpredictable, and delays could push commercialization timelines years into the future. Manufacturing at scale is unproven, and the company has yet to demonstrate that its reactors can be deployed economically. Oklo is also exposed to competitive risk from other SMR developers and established utilities that could capture AI power demand with existing assets. The stock has fallen nearly 50% from its peak, and analysts have flagged valuation concerns that could persist even after further declines.

Who Each Stock Is For

Vistra stock is for investors who want immediate exposure to AI power demand with established operations and contracted revenue. It's a lower-risk way to play the nuclear energy stocks theme without betting on unproven technology. If you want cash flow, dividends, and a diversified energy portfolio with upside from AI infrastructure growth, Vistra fits.

Constellation energy stock is for investors seeking a pure-play nuclear operator with scale, stability, and multiple hyperscaler contracts. It's a middle-ground bet: less speculative than Oklo, more focused than Vistra. Constellation trades at a more attractive valuation than it did at its highs, and it offers a steadier ship for investors uncomfortable with Oklo's volatility. If you believe AI data centers will drive sustained demand for carbon-free baseload power, Constellation is the cleanest way to express that view.

Oklo stock is for investors with high risk tolerance who want exposure to transformative technology and are willing to accept volatility, execution risk, and a multi-year timeline. If Oklo delivers on its vision, it could become a dominant player in next-generation nuclear. If it stumbles, the stock could fall further. This is a binary bet on advanced reactor technology, not a steady income play.

Frequently Asked Questions

Is Oklo a good stock to buy? Oklo stock is a speculative bet on advanced nuclear technology, not a traditional investment. The company is pre-revenue, unprofitable, and faces significant execution and regulatory risk. It's down nearly 50% from its peak, and analysts have raised valuation concerns even at current levels. That said, if Oklo successfully commercializes its small modular reactors and scales production, the upside could be substantial. The Meta agreement for up to 1.2 gigawatts of capacity signals real interest from hyperscalers, but availability isn't expected until 2030 at the earliest. For investors with high risk tolerance and a long time horizon, Oklo offers differentiated exposure to the AI power boom. For those seeking near-term cash flow or proven operations, it's not a fit.

Vistra vs Constellation: what's the difference? Vistra and Constellation are both established nuclear operators, but they differ in focus and portfolio composition. Constellation is a pure-play nuclear company that owns the largest nuclear fleet in the U.S. and generates revenue almost entirely from carbon-free baseload power. Vistra operates a more diversified portfolio that includes nuclear, natural gas, and renewables, which gives it broader exposure to wholesale power markets. Both have signed long-term contracts with hyperscalers, but Vistra's Meta deal is more publicly detailed: over 2.1 gigawatts from existing plants plus uprates. Constellation trades at roughly 25.5 times forward earnings and is down about 30% from highs, while Vistra's valuation reflects its diversified asset base. If you want pure nuclear exposure with scale, Constellation is cleaner. If you want nuclear upside plus diversification, Vistra offers that balance.

What are the best nuclear stocks for AI? The best nuclear stocks for AI depend on your risk tolerance and investment timeline. Vistra offers the most immediate exposure through its Meta contracts and operating nuclear plants: it's generating cash flow now and benefits directly from AI data center demand. Constellation Energy provides the largest nuclear fleet in the U.S. and has signed multiple hyperscaler contracts, making it a stable, diversified play on AI infrastructure stocks. Oklo represents the highest growth potential but also the highest risk, with advanced small modular reactors that could power AI data centers starting in 2030: if execution goes as planned. For conservative investors, Vistra and Constellation are the safer bets. For aggressive investors willing to accept volatility and development risk, Oklo offers transformative upside.

The Latte Take

I'm watching all three, but I'm not treating them as interchangeable. Vistra and Constellation are established operators with real cash flows, contracted revenue, and proven track records. They're plays on sustained AI power demand with manageable downside. Oklo is a different animal: it's a development-stage technology bet that could either dominate the next generation of AI infrastructure or stumble through years of execution challenges.

If I had to pick one for stability, I'd lean Constellation. It's the purest nuclear exposure with the largest fleet and a valuation that's more attractive than it was six months ago. If I wanted near-term AI upside with diversification, Vistra's Meta contracts make it compelling. And if I had a small allocation for speculative growth, Oklo would fit: but only if I could stomach the volatility and accept that the timeline is uncertain.

The AI power boom is real. The question is whether you want to bet on the plants already running or the reactors still being built.

George