IRVING, Texas, March 17, 2026 /PRNewswire/ -- Vistra Corp. (NYSE: VST) today announced that Fitch Ratings has upgraded the company's long-term issuer default rating to investment grade, further strengthening Vistra's credit profile. The action follows S&P Global Ratings' upgrade of Vistra's issuer credit rating to investment grade on Dec. 2, 2025, marking the second investment grade credit rating from a major credit rating agency.