Constellation Energy (CEG) Stock After Hours Today (Dec. 17, 2025): Why Shares Fell and What to Watch Before Thursday’s Open
Constellation Energy Corporation (NASDAQ: CEG) ended Wednesday, December 17, 2025 with a sharp selloff during regular trading—then bounced in after-hours action as late-breaking grid-market headlines hit the tape. CEG closed the session at $340.97, down 6.74%, after trading between $372.00 (high) and $334.18 (low) on volume of roughly 4.57 million shares. StockAnalysisIn after-hours trading, CEG was quoted around $348.58 (+2.23%) as of 6:13 p.m. ET. StockAnalysis For investors waking up ahead of the Thursday, Dec. 18 open, the message is clear: this stock is being driven by two forces at once—AI/data-center sentiment (a near-term trading driver) and power-market fundamentals (a