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 . while the financial impacts of winter storm uri to vistra are not yet finalized , vistra management preliminarily estimates the one-time adverse impact on pre-tax net income will be in the range of approximately $ 900 million to $ 1.3 billion . this estimated range is preliminary and based on currently available information and management estimates . the final amount of the estimated loss is subject to a variety of factors including , but not limited to , outstanding pricing , load , and settlement data from ercot ( which is released at various intervals during a period of up to 180 days after the transaction day ) ; the outcome of potential litigation arising from this event ( including any litigation that we may pursue or be a party to ) ; or any corrective action taken by the state of texas , ercot , the rct , or the puct to resettle pricing across any portion of the supply chain that is currently being considered or may be considered by any such parties . there have already been several announced efforts by the state and federal governments and regulatory agencies to investigate and determine the causes of this event and its impact on consumers . we have received a civil investigative demand from the attorney general of texas as well as a request for information from ercot related to this event and may receive additional inquiries . we are cooperating with these entities and are working to respond to these requests . those efforts may result in changes in regulations that impact our industry including but not limited to additional requirements for winterization of various facets of the electricity supply chain including generation , transmission , and fuel supply ; improvements in coordination among the various participants in the electricity supply chain during any future event ; potential revisions to the way in which the ercot market compensates and incentivizes the continued operation of assets that only run during times of scarcity ; and potential changes to the types of plans permitted to be marketed to residential customers . we are continuing to monitor this situation as it develops but at this time can not estimate any impacts of any legislative or regulatory changes or actions ( including enforcement actions that may be brought against various market participants ) that may occur as a result of the event on our business , financial condition , results of operations , or cash flows . as of december 31 , 2020 , vistra had total available liquidity of approximately $ 2.4 billion , which was primarily comprised of cash and availability under its revolving credit facility . during this storm event , vistra was required to post a significant amount of collateral , including to ercot , clearinghouses for natural gas and power transactions and other trading counterparties . despite these posting requirements , vistra has consistently maintained , and it continues to maintain , sufficient liquidity to conduct its operations in the ordinary course . as of february 25 , 2021 , vistra had more than $ 1.5 billion of cash and availability under its revolving credit facility to meet any of its liquidity needs . 52 in response to the storm , vistra committed to donate $ 5 million to assist texas communities and individuals meet their most pressing needs , including support for food banks and food pantries , critical needs , bill payment assistance , and more . vistra also assured residential customers across its retail brands that they will not see any near-term impact on their rates due to the winter weather event , though bills may increase due to high usage during the cold weather period in february . investments in clean energy and co2 reductions in september 2020 , we announced the planned development of up to 668 mw of solar photovoltaic power generation facilities and 260 mw of battery ess in texas . we will only invest in these growth projects if we are confident in the expected returns . see note 3 to the financial statements for a summary of our solar and battery energy storage projects . in september 2020 and december 2020 , we announced our intention to retire ( a ) all of our remaining coal generation facilities in illinois and ohio , ( b ) one coal generation facility in texas and ( c ) one natural gas facility in illinois , no later than year-end 2027 due to economic challenges , including incremental expenditures that would be required to comply with the ccr rule and elg rule ( see note 13 to the financial statements ) , and in furtherance of our efforts to significantly reduce our carbon footprint . see note 4 to the financial statements for a summary of these planned generation retirements as well as our generation plant retirements in 2019. covid-19 pandemic with the global outbreak of the novel coronavirus ( covid-19 ) and the declaration of a pandemic by the world health organization on march 11 , 2020 , the u.s. government has deemed electricity generation , transmission and distribution as `` critical infrastructure `` providing essential services during this global emergency . as a provider of critical infrastructure , vistra has an obligation to provide critically needed power to homes , businesses , hospitals and other customers . vistra remains focused on protecting the health and well-being of its employees and the communities in which it operates while assuring the continuity of its business operations . we have updated and implemented our company-wide pandemic plan to address specific aspects of the covid-19 pandemic to guide our emergency response , business continuity , and the precautionary measures we are taking on behalf of employees and the public . story_separator_special_tag we participate in industry groups and with regulators to keep current on the latest developments in nuclear safety , operation and maintenance and on emerging threats and mitigating techniques . these groups include , but are not limited to , the nrc , the institute of nuclear power operations ( inpo ) and the nuclear energy institute ( nei ) . we also apply the knowledge gained through our continuing investment in technology , processes and services to improve our operations and to detect , mitigate and protect our nuclear generation assets . management continues to focus on the safe , reliable and efficient operations at the facility . cyber/data security and infrastructure protection risk a breach of cyber/data security measures that impairs our information technology infrastructure could disrupt normal business operations and affect our ability to control our generation assets , access retail customer information and limit communication with third parties . any loss of confidential or proprietary data through a breach could materially affect our reputation , including our txu energy tm , ambit energy , value based brands , dynegy energy services , homefield energy , trieagle energy , public power and u.s. gas & electric brands , expose the company to legal claims and regulatory scrutiny or impair our ability to execute on business strategies . 59 we participate in industry groups and with regulators to remain current on emerging threats and mitigating techniques . these groups include , but are not limited to , the u.s. cyber emergency response team , the national electric sector cyber security organization , the nrc and nerc . while the company has not experienced a cyber/data event causing any material operational , reputational or financial impact , we recognize the growing threat within the general market place and our industry , and are proactively making strategic investments in our perimeter and internal defenses , cyber/data security operations center and regulatory compliance activities . we also apply the knowledge gained through industry and government organizations to continuously improve our technology , processes and services to detect , mitigate and protect our cyber and data assets . seasonality the demand for and market prices of electricity and natural gas are affected by weather . as a result , our operating results are impacted by extreme or sustained weather conditions and may fluctuate on a seasonal basis . typically , demand for and the price of electricity is higher in the summer and winter seasons , when the temperatures are more extreme , and the demand for and price of natural gas is also generally higher in the winter . more severe weather conditions such as heat waves or extreme winter weather have made , and may make such fluctuations more pronounced . the pattern of this fluctuation may change depending on , among other things , the retail load served and the terms of contracts to purchase or sell electricity . application of critical accounting policies our significant accounting policies are discussed in note 1 to the financial statements . we follow accounting principles generally accepted in the u.s. application of these accounting policies in the preparation of our consolidated financial statements requires management to make estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and revenues and expenses during the periods covered . the following is a summary of certain critical accounting policies that are impacted by judgments and uncertainties and under which different amounts might be reported using different assumptions or estimation methodologies . purchase accounting on november 1 , 2019 , an indirect , wholly owned subsidiary of vistra completed the ambit transaction . on july 15 , 2019 , an indirect , wholly owned subsidiary of vistra completed the crius transaction . each of the ambit transaction and crius transaction , respectively , was accounted for in accordance with asc 805 , business combinations ( asc 805 ) , with identifiable assets acquired and liabilities assumed recorded at their estimated fair values on the ambit acquisition date and the crius acquisition date , respectively . see note 2 to the financial statements for the purchase price allocations for both the ambit transaction and crius transaction as well as the related adjustments through the respective measurement periods . determining fair values of assets acquired and liabilities assumed requires significant estimates and judgments . we determine fair value based on the estimated price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date . the acquired assets that involved the most subjectivity in determining fair value consisted of the customer relationship intangible assets . the assignment of fair value to the identifiable intangible assets requires judgment . we apply an income-based valuation methodology in measuring the customer relationships acquired , which include certain assumptions such as forecasted future cash flows , customer attrition rates , and discount rates . customer relationship intangibles assets are generally amortized using an accelerated method based on historical customer attrition rates and reflecting the expected pattern in which the economic benefits are realized over their estimated useful lives . on the merger date , dynegy merged with and into vistra , with vistra continuing as the surviving corporation . the merger was accounted for in accordance with asc 805 , with identifiable assets acquired and liabilities assumed recorded at their estimated fair values on the merger date . vistra is the acquirer for both federal tax and accounting purposes . the combined results of operations are reported in our consolidated financial statements beginning as of the merger date . see note 2 to the financial statements . 60 the acquired assets and liabilities that involved the most subjectivity in determining fair value consisted of property , plant and equipment and executory contracts , primarily long-term service agreements for maintenance of power plants , a unit-specific power sales agreement and

debt activity see note 10 to the financial statements for details of the receivables facility and repurchase facility and note 11 to the financial statements for details of the vistra operations credit facilities and other long-term debt . available liquidity the following table summarizes changes in available liquidity for the year ended december 31 , 2020 : replace_table_token_37_th ( a ) excludes amounts available to be borrowed under the receivables facility and the repurchase facility , respectively . see note 10 to the financial statements for detail on our account receivable financing . the $ 673 million increase in available liquidity for the year ended december 31 , 2020 was primarily driven by cash from operations , repayments of cash borrowings under the revolving credit facility and a reduction of letters of credit outstanding under the revolving credit facility reflecting the issuance of $ 303 million of letters of credit under the secured loc facilities , partially offset by $ 1.259 billion of capital expenditures ( including ltsa prepayments , nuclear fuel and development and growth expenditures ) , $ 747 million principal amount of outstanding vistra unsecured senior notes redeemed in 2020 , $ 266 million in dividends paid to stockholders , the maturity of a $ 250 million alternate loc facility and $ 100 million of term loans under the vistra operation credit facility repaidin march 2020. during the winter storm uri event , vistra was required to post a significant amount of collateral , including to ercot , clearinghouses for natural gas and power transactions and other trading counterparties .


 Write a concise suspicious activity report of the following text delimited by triple backquotes. Return your response as a formal report which covers the key points highlighting the location,dates,entity names and account holder information in chronological order of the text.
     ```debt activity see note 10 to the financial statements for details of the receivables facility and repurchase facility and note 11 to the financial statements for details of the vistra operations credit facilities and other long-term debt . available liquidity the following table summarizes changes in available liquidity for the year ended december 31 , 2020 : replace_table_token_37_th ( a ) excludes amounts available to be borrowed under the receivables facility and the repurchase facility , respectively . see note 10 to the financial statements for detail on our account receivable financing . the $ 673 million increase in available liquidity for the year ended december 31 , 2020 was primarily driven by cash from operations , repayments of cash borrowings under the revolving credit facility and a reduction of letters of credit outstanding under the revolving credit facility reflecting the issuance of $ 303 million of letters of credit under the secured loc facilities , partially offset by $ 1.259 billion of capital expenditures ( including ltsa prepayments , nuclear fuel and development and growth expenditures ) , $ 747 million principal amount of outstanding vistra unsecured senior notes redeemed in 2020 , $ 266 million in dividends paid to stockholders , the maturity of a $ 250 million alternate loc facility and $ 100 million of term loans under the vistra operation credit facility repaidin march 2020. during the winter storm uri event , vistra was required to post a significant amount of collateral , including to ercot , clearinghouses for natural gas and power transactions and other trading counterparties .
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 Suspicious Activity Report : 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 . while the financial impacts of winter storm uri to vistra are not yet finalized , vistra management preliminarily estimates the one-time adverse impact on pre-tax net income will be in the range of approximately $ 900 million to $ 1.3 billion . this estimated range is preliminary and based on currently available information and management estimates . the final amount of the estimated loss is subject to a variety of factors including , but not limited to , outstanding pricing , load , and settlement data from ercot ( which is released at various intervals during a period of up to 180 days after the transaction day ) ; the outcome of potential litigation arising from this event ( including any litigation that we may pursue or be a party to ) ; or any corrective action taken by the state of texas , ercot , the rct , or the puct to resettle pricing across any portion of the supply chain that is currently being considered or may be considered by any such parties . there have already been several announced efforts by the state and federal governments and regulatory agencies to investigate and determine the causes of this event and its impact on consumers . we have received a civil investigative demand from the attorney general of texas as well as a request for information from ercot related to this event and may receive additional inquiries . we are cooperating with these entities and are working to respond to these requests . those efforts may result in changes in regulations that impact our industry including but not limited to additional requirements for winterization of various facets of the electricity supply chain including generation , transmission , and fuel supply ; improvements in coordination among the various participants in the electricity supply chain during any future event ; potential revisions to the way in which the ercot market compensates and incentivizes the continued operation of assets that only run during times of scarcity ; and potential changes to the types of plans permitted to be marketed to residential customers . we are continuing to monitor this situation as it develops but at this time can not estimate any impacts of any legislative or regulatory changes or actions ( including enforcement actions that may be brought against various market participants ) that may occur as a result of the event on our business , financial condition , results of operations , or cash flows . as of december 31 , 2020 , vistra had total available liquidity of approximately $ 2.4 billion , which was primarily comprised of cash and availability under its revolving credit facility . during this storm event , vistra was required to post a significant amount of collateral , including to ercot , clearinghouses for natural gas and power transactions and other trading counterparties . despite these posting requirements , vistra has consistently maintained , and it continues to maintain , sufficient liquidity to conduct its operations in the ordinary course . as of february 25 , 2021 , vistra had more than $ 1.5 billion of cash and availability under its revolving credit facility to meet any of its liquidity needs . 52 in response to the storm , vistra committed to donate $ 5 million to assist texas communities and individuals meet their most pressing needs , including support for food banks and food pantries , critical needs , bill payment assistance , and more . vistra also assured residential customers across its retail brands that they will not see any near-term impact on their rates due to the winter weather event , though bills may increase due to high usage during the cold weather period in february . investments in clean energy and co2 reductions in september 2020 , we announced the planned development of up to 668 mw of solar photovoltaic power generation facilities and 260 mw of battery ess in texas . we will only invest in these growth projects if we are confident in the expected returns . see note 3 to the financial statements for a summary of our solar and battery energy storage projects . in september 2020 and december 2020 , we announced our intention to retire ( a ) all of our remaining coal generation facilities in illinois and ohio , ( b ) one coal generation facility in texas and ( c ) one natural gas facility in illinois , no later than year-end 2027 due to economic challenges , including incremental expenditures that would be required to comply with the ccr rule and elg rule ( see note 13 to the financial statements ) , and in furtherance of our efforts to significantly reduce our carbon footprint . see note 4 to the financial statements for a summary of these planned generation retirements as well as our generation plant retirements in 2019. covid-19 pandemic with the global outbreak of the novel coronavirus ( covid-19 ) and the declaration of a pandemic by the world health organization on march 11 , 2020 , the u.s. government has deemed electricity generation , transmission and distribution as `` critical infrastructure `` providing essential services during this global emergency . as a provider of critical infrastructure , vistra has an obligation to provide critically needed power to homes , businesses , hospitals and other customers . vistra remains focused on protecting the health and well-being of its employees and the communities in which it operates while assuring the continuity of its business operations . we have updated and implemented our company-wide pandemic plan to address specific aspects of the covid-19 pandemic to guide our emergency response , business continuity , and the precautionary measures we are taking on behalf of employees and the public . story_separator_special_tag we participate in industry groups and with regulators to keep current on the latest developments in nuclear safety , operation and maintenance and on emerging threats and mitigating techniques . these groups include , but are not limited to , the nrc , the institute of nuclear power operations ( inpo ) and the nuclear energy institute ( nei ) . we also apply the knowledge gained through our continuing investment in technology , processes and services to improve our operations and to detect , mitigate and protect our nuclear generation assets . management continues to focus on the safe , reliable and efficient operations at the facility . cyber/data security and infrastructure protection risk a breach of cyber/data security measures that impairs our information technology infrastructure could disrupt normal business operations and affect our ability to control our generation assets , access retail customer information and limit communication with third parties . any loss of confidential or proprietary data through a breach could materially affect our reputation , including our txu energy tm , ambit energy , value based brands , dynegy energy services , homefield energy , trieagle energy , public power and u.s. gas & electric brands , expose the company to legal claims and regulatory scrutiny or impair our ability to execute on business strategies . 59 we participate in industry groups and with regulators to remain current on emerging threats and mitigating techniques . these groups include , but are not limited to , the u.s. cyber emergency response team , the national electric sector cyber security organization , the nrc and nerc . while the company has not experienced a cyber/data event causing any material operational , reputational or financial impact , we recognize the growing threat within the general market place and our industry , and are proactively making strategic investments in our perimeter and internal defenses , cyber/data security operations center and regulatory compliance activities . we also apply the knowledge gained through industry and government organizations to continuously improve our technology , processes and services to detect , mitigate and protect our cyber and data assets . seasonality the demand for and market prices of electricity and natural gas are affected by weather . as a result , our operating results are impacted by extreme or sustained weather conditions and may fluctuate on a seasonal basis . typically , demand for and the price of electricity is higher in the summer and winter seasons , when the temperatures are more extreme , and the demand for and price of natural gas is also generally higher in the winter . more severe weather conditions such as heat waves or extreme winter weather have made , and may make such fluctuations more pronounced . the pattern of this fluctuation may change depending on , among other things , the retail load served and the terms of contracts to purchase or sell electricity . application of critical accounting policies our significant accounting policies are discussed in note 1 to the financial statements . we follow accounting principles generally accepted in the u.s. application of these accounting policies in the preparation of our consolidated financial statements requires management to make estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and revenues and expenses during the periods covered . the following is a summary of certain critical accounting policies that are impacted by judgments and uncertainties and under which different amounts might be reported using different assumptions or estimation methodologies . purchase accounting on november 1 , 2019 , an indirect , wholly owned subsidiary of vistra completed the ambit transaction . on july 15 , 2019 , an indirect , wholly owned subsidiary of vistra completed the crius transaction . each of the ambit transaction and crius transaction , respectively , was accounted for in accordance with asc 805 , business combinations ( asc 805 ) , with identifiable assets acquired and liabilities assumed recorded at their estimated fair values on the ambit acquisition date and the crius acquisition date , respectively . see note 2 to the financial statements for the purchase price allocations for both the ambit transaction and crius transaction as well as the related adjustments through the respective measurement periods . determining fair values of assets acquired and liabilities assumed requires significant estimates and judgments . we determine fair value based on the estimated price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date . the acquired assets that involved the most subjectivity in determining fair value consisted of the customer relationship intangible assets . the assignment of fair value to the identifiable intangible assets requires judgment . we apply an income-based valuation methodology in measuring the customer relationships acquired , which include certain assumptions such as forecasted future cash flows , customer attrition rates , and discount rates . customer relationship intangibles assets are generally amortized using an accelerated method based on historical customer attrition rates and reflecting the expected pattern in which the economic benefits are realized over their estimated useful lives . on the merger date , dynegy merged with and into vistra , with vistra continuing as the surviving corporation . the merger was accounted for in accordance with asc 805 , with identifiable assets acquired and liabilities assumed recorded at their estimated fair values on the merger date . vistra is the acquirer for both federal tax and accounting purposes . the combined results of operations are reported in our consolidated financial statements beginning as of the merger date . see note 2 to the financial statements . 60 the acquired assets and liabilities that involved the most subjectivity in determining fair value consisted of property , plant and equipment and executory contracts , primarily long-term service agreements for maintenance of power plants , a unit-specific power sales agreement and

