Page 1

VISTRA NEWS RELEASE Vistra Updates Financial Impact of Winter Storm Uri and Reissues 2021 Guidance Exhibit 99.1 IRVING , Texas -April 26 , 2021 Vistra ( NYSE : VST ) announced today that it is : Estimating the financial impact of Winter Storm Uri ( “ Uri ” ) on 2021 Ongoing Operations Adjusted EBITDA 1 and Ongoing Operations Adjusted Free Cash Flow before Growth ( FCFbG ) 1 at ~ $ ( 1,600 ) million , including self - help initiatives . Reissuing 2021 Ongoing Operations Adjusted EBITDA 1 and Ongoing Operations Adjusted FCFbG 1 guidance ranges at $ 1,475 to $ 1,875 million and $ 200 to $ 600 million , respectively . Providing an update on its 2021 capital allocation plan . Hosting an investor update call today at 8 a.m. EDT ( 7 a.m. CDT ) in lieu of its regularly scheduled quarterly earnings conference call ; filing its Quarterly Report on Form 10 - Q for the first quarter of 2021 and posting the related investor materials to its website on May 5 , 2021 . Winter Storm Uri Since its initial announcement regarding the estimated financial impact of Uri on Feb. 26 , 2021 , Vistra has received additional customer load information , which drove a negative variance to its previous estimate of $ ( 900 ) million to $ ( 1,300 ) million . Vistra also had a line of sight to relatively high probability self - help initiatives that , until mid - April , kept the net estimate of the 2021 Adjusted EBITDA impact at the high end of this previous range , with knowledge that ERCOT's 55 - day resettlement statements would be forthcoming . These self - help initiatives include the monetization of certain commercial positions , generation savings from lower O & M project work , retail savings and forecasted performance , and IT and SG & A savings , which are expected to total ~ $ 500 million in the balance of the year . In mid - April , Vistra received the 55 - day resettlement statements from ERCOT , which drove an estimated negative variance of more than $ 200 million . Vistra now estimates the net financial impact of Uri on its 2021 Ongoing Operations Adjusted EBITDA 1 and Ongoing Operations Adjusted FCFbG 1 is ~ $ ( 1,600 ) million . This estimate includes the expected benefit of the self - help initiatives , but assumes no recovery from potential successful outcomes of various legal and regulatory challenges related to Uri . Vistra estimates the entire 2021 Adjusted EBITDA impact from the storm was less than the negative impact from gas deliverability issues and the incredibly high costs to procure gas . Vistra's firm gas contracts that were not honored by third parties led to the company procuring replacement gas at incredibly high costs , while the lack of physical gas and insufficient pressures on the pipelines impacted the company's ability to generate power at full capacity . As a result of these challenges , Vistra had to procure power in the ERCOT market at prices at or near the price cap to meet its supply obligations . Absent these issues with gas deliverability and increased gas costs , Vistra estimates that the 2021 Adjusted EBITDA impact of Uri would have been a slight positive . Vistra - Press Release April 26 , 2021 , Page 2 " Vistra positioned itself to handle the unprecedented Winter Storm Uri in Texas and executed well in the areas that we could control . The storm led to a confluence of unpredictable events and substantially altered the company's risk profile , driven by issues with the integrated gas and electric systems , principally impaired gas deliverability , that we had never before seen . We are obviously very disappointed with the financial loss as a result of the effects of Uri and it is even more difficult to accept given our team members ' preparation and execution before , during , and after the storm , " said Curt Morgan , Vistra's chief executive officer . " The results do not reflect our performance ; however , we understand the reality in front of us and are prepared to move the company forward . We have a strong core to build from and have faith in our business model and strategic direction , especially as we implement a number of measures to mitigate the risks we observed from the winter storm event . Vistra is confident in the company's ability to bounce back in 2021 and get back on track with our transformation , the execution of our long - term capital allocation plan , and creating value for our stakeholders over the long - term . " ( 1 ) Excludes the Asset Closure segment . Ongoing Operations Adjusted EBITDA and Ongoing Operations Adjusted FCFbG are non - GAAP financial measures . See the " Non - GAAP Reconciliation " tables for further detail . Reissued 2021 Guidance