Constellation Energy shares slid nearly 10% in the latest session after the Trump administration, in partnership with governors from Maryland and Pennsylvania and the PJM grid operator, unveiled a proposal to impose price caps on existing power generation in the mid-Atlantic region. The move, aimed at protecting end consumers from rapidly rising electricity costs, undercuts the company’s ability to capitalize on historically high rates fueled by surging demand from AI data centers. Investors reacted swiftly, marking the steepest one-day decline in over a year.

The non-binding statement of principles calls for large technology firms to bid on 15-year contracts that would underwrite the construction of at least six gigawatts of new capacity—equivalent to six nuclear power plants—by 2027. While it secures funding for additional generation to address a projected shortfall, the agreement also contemplates caps on prices charged by Constellation’s existing nuclear and gas-fired assets. With roughly 69% of the company’s generation currently sold into PJM, and an expected 49% post-Calpine acquisition, the framework represents a fundamental shift in how the utility can monetize its legacy fleet.

Constellation’s revenue from PJM surged in 2025, contributing to a stock rally of nearly 58% as AI data-center operators bid up wholesale prices. The proposed rate caps threaten to erode the windfall margins the company has realized on existing capacity, which historically outperformed greenfield project returns. While new plant construction agreements could stabilize long-term cash flows, they may yield lower gross margins than the current pricing environment. This dynamic has prompted analysts to reassess near-term earnings growth and adjust profit forecasts downward.

Going forward, Constellation must balance potential benefits from tech-backed construction contracts against margin compression on its established nuclear fleet. The company’s ability to negotiate favorable contract terms, secure regulatory approvals and optimize capital deployment will be critical. Investors will be watching upcoming earnings guidance, regulatory filings and stakeholder negotiations in PJM for signals on how management plans to mitigate downside risk and preserve shareholder value under the new market regime.