Constellation Energy is trading 4.07% up at $269.38 on October 21, 2026, after its 20-year Amazon power purchase agreement for expansion and relicensing of Maryland’s Calvert Cliffs nuclear plant. - Amazon’s commitment supports $3 billion in upgrades, including 690 MW of power. - About 190 MW of additional emissions-free capacity is expected in 2030–2032; the deal provides revenue certainty for relicensing. - Coverage linked the deal to Constellation Energy being among S&P 500 leaders; broader markets also rose.