NEW YORK, December 30, 2025, 23:22 ET — Market closed
- Constellation Energy (CEG) closed down 0.4% at $357.12 on Tuesday.
- Nuclear power names stayed on traders’ radar as utilities chase new generation for data center demand.
- Investors are watching the Calpine acquisition timeline, divestiture requirements and the next earnings date.
Constellation Energy Corporation shares slipped 0.4% to $357.12 on Tuesday, ending the session lower as the market headed into the final trading days of the year.
The move matters because Constellation has become a key proxy for bets that electricity demand from artificial intelligence data centers will keep tightening U.S. power markets, lifting the value of steady, around-the-clock generation such as nuclear. Nuclear sentiment was in focus again after Duke Energy said it applied to the U.S. Nuclear Regulatory Commission for an early site permit for a potential new nuclear facility in North Carolina.
Constellation’s valuation debate is also tied to its pending $26.6 billion acquisition of privately held Calpine, a deal that would add a large fleet of natural gas plants and expand Constellation’s exposure to wholesale power prices.
Shares traded between $355.50 and $361.40 on the day. Vistra added 0.5% while NRG Energy fell 0.4%, underscoring mixed trading in U.S. power producers.
Company filings showed no new current report after Dec. 23, when Constellation disclosed extensions tied to private exchange offers and consent solicitations for certain Calpine notes. An exchange offer is a deal to swap one set of bonds for another, typically to align debt terms ahead of a transaction.
Regulatory clearance remains the key swing factor for the Calpine transaction. The U.S. Justice Department said on Dec. 5 it would require divestitures of six power plants in Delaware, Pennsylvania and Texas to address antitrust concerns, and said the settlement is subject to court approval after a public-comment process under the Tunney Act, which governs review of antitrust settlements.
Constellation has said the Federal Energy Regulatory Commission also approved the deal, conditioned on divestitures of Calpine assets in the Mid-Atlantic market.
The nuclear thesis for Constellation also leans on long-term power purchase agreements, or PPAs — contracts that lock in electricity sales over many years. In a Dec. 12 statement, Constellation said its 20-year PPA with Microsoft helped launch the Crane Clean Energy Center restart, with executive Dan Eggers saying, “This project will create more than 3,000 jobs and put 835 MW of clean, reliable power back on the grid.” Constellation
Traders have been tracking PJM Interconnection, the 13-state grid operator that runs the largest U.S. capacity market. A capacity auction pays generators to be available in the future — essentially a reliability insurance premium — and Reuters reported this month’s PJM auction cleared at record prices, highlighting a supply crunch as data center demand rises.
CEG sits about 13% below its 52-week high and more than double its 52-week low, leaving investors split between momentum and valuation concerns after a sharp run in 2025.
Before the next session, investors will watch for any concrete updates on divestiture execution and closing mechanics for Calpine, including the bond exchange timeline disclosed in the Dec. 23 filing.
The next scheduled catalyst is earnings. Nasdaq lists Constellation’s next report date as an estimate of Feb. 17, 2026, and traders will be looking for updates on 2026 power-price exposure, nuclear performance and how management frames integration and cash flow once the Calpine deal closes.
