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TABLE OF CONTENTS ( Mark One ) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( D ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( D ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from STAR PEAK ENERGY TRANSITION CORP . ( Exact name of registrant as specified in its charter ) 001-39455 ( Commission File Number ) Delaware ( State or other jurisdiction of incorporation or organization ) 1603 Orrington Avenue , 13th Floor Evanston , Illinois ( Address of principal executive offices ) Registrant's telephone number , including area code : ( 847 ) 905-4500 Not Applicable ( Former name or former address , if changed since last report ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol : Title of Each Class : Units , each consisting of one share of Class A common stock , $ 0.0001 par value , and one - third of one warrant Shares of Class A common stock included as part of the units Warrants included as part of the units , each whole warrant exercisable for one share of Class A common stock at an exercise price of $ 11.50 STPK.U STPK to STPK WS Accelerated filer 85-1972187 ( I.R.S. Employer Identification Number ) Name of Each Exchange on Which Registered : The New York Stock Exchange 60201 ( Zip Code ) Securities registered pursuant to Section 12 ( g ) of the Act : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Exchange Act . Yes No Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes No Non - accelerated filer > The New York Stock Exchange Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( § 232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit and post such files ) . Yes No The New York Stock Exchange Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company or an emerging growth company . See definition of " large accelerated filer , " " accelerated filer , “ smaller reporting company " and " emerging growth company " in Rule 12b - 2 of the Exchange Act . Large accelerated filer Documents Incorporated by Reference : None . Smaller reporting company Emerging growth company If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No As of June 30 , 2020 , the last business day of the registrant's most recently completed second fiscal quarter , the registrant's securities were not publicly traded . The registrant's units began trading on The New York Stock Exchange ( " NYSE " ) on August 17 , 2020 and the registrant's shares of Class A common stock , par value $ 0.0001 ( the " Class A common stock " ) and warrants began trading on the NYSE on October 8 , 2020. The aggregate market value of the common stock outstanding , other than shares held by persons who may be deemed affiliates of the registrant , computed by reference to the closing sales price for the shares of common stock on December 31 , 2020 , as reported on the NYSE , was $ 784,814,992 ( based on the closing sales price of the Class A common stock on December 31 , 2020 of $ 20.46 ) . As of February 22 , 2021 , 38,358,504 shares of Class A common stock , par value $ 0.0001 , and 9,589,626 shares of Class B common stock , par value $ 0.0001 , were issued and outstanding .