Constellation Energy stock slides as Calpine deal closes, investors eye integration updates
New York, Jan 8, 2026, 15:04 EST — Regular session Constellation Energy shares were down about 4.2% at $324.54 in mid-afternoon trading on Thursday, extending a two-day slide as investors digested the close of its Calpine acquisition. The stock fell 4.5% on Wednesday to $338.63, its third straight session of losses. MarketWatch Constellation said on Wednesday it completed the purchase of Calpine from Energy Capital Partners, a deal that pushes the nuclear-heavy generator deeper into natural gas and geothermal power. CEO Joe Dominguez said U.S. demand for power “is surging,” pointing to data centers and other big loads, while Calpine