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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 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 Delaware ( State or other jurisdiction of incorporation or organization ) 16640 Stagg Street , Van Nuys , California ( Address of principal executive offices ) For the fiscal year ended March 31 , 2021 Title of each class Common Stock , par value $ .001 per share Series B Junior Participating Preferred Stock Purchase Rights CAPSTONE GREEN ENERGY CORPORATION ( Exact name of registrant as specified in its charter ) or For the transition period from Commission file number 001-15957 to Large accelerated filer Emerging growth company ( 818 ) 734-5300 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) CGRN Securities registered pursuant to Section 12 ( g ) of the Act : None No Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the 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 Accelerated filer 95-4180883 ( I.R.S. Employer Identification No. ) 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 such files ) . Yes No 91406 ( Zip Code ) Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , smaller reporting company or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer ” , “ smaller reporting company ” and “ emerging growth company " in Rule 12b - 2 of the Exchange Act . Name of exchange on which registered NASDAQ Capital Market Non - accelerated filer > Smaller reporting 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 As of June 10 , 2021 , there were 12,926,026 , shares of the registrant's Common Stock outstanding . DOCUMENTS INCORPORATED BY REFERENCE Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . Yes No The aggregate market value of the shares of Common Stock of the registrant held by non - affiliates on September 30 , 2020 was approximately $ 51.7 million . Portions of the definitive proxy statement relating to the registrant's 2021 annual meeting of stockholders are incorporated by reference into Part III of this report to the extent described therein .