Vistra Corp., formerly Vistra Energy Corp, is a holding company. The Company operates an integrated retail and generation business in markets throughout the United States. Through its subsidiaries, it is engaged in electricity market activities, including electricity generation, wholesale energy sales and purchases, commodity risk management and retail sales of electricity to end users. It operates through segments, including Retail; Electric Reliability Council of Texas, Inc. (ERCOT); PJM Interconnection, LLC (PJM); NY/NE (comprising New York Independent System Operator (NYISO) and Independent System Operator New England (ISO-NE)); Midcontinent Independent System Operator, Inc. (MISO), and Asset Closure. Its generation fleet totals approximately 40,000 megawatt (MW) of generation capacity with a portfolio of natural gas, nuclear, coal and solar facilities.