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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K ( Mark One ) 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 For the fiscal year ended December 31 , 2020 OR Delaware ( State or other jurisdiction of incorporation or organization ) For the transition period from Commission file number : 001-37924 BlackLine , Inc. ( Exact name of Registrant as specified in its charter ) to 21300 Victory Boulevard , 12th Floor Woodland Hills , CA 91367 ( Address of principal executive offices , including zip code ) ( 818 ) 223-9008 ( Registrant's telephone number , including area code ) Title of each class Common Stock , par value $ 0.01 per share Large accelerated filer Non - accelerated filer 46-3354276 ( I.R.S. Employer Identification Number ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) BL Securities registered pursuant to Section 12 ( g ) of the Act : None Name of each exchange on which registered NASDAQ Global Select Market Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes x No o Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Securities Exchange Act of 1934 ( the " Exchange Act " ) . Yes o No x Indicate by check mark whether the registrant : ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Exchange Act 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 x No o 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 x No o 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 the definitions of " large accelerated filer , " " accelerated filer " , " smaller reporting company " and " emerging growth company " in Rule 12b - 2 of the Exchange Act .: Accelerated filer Smaller reporting company Emerging growth company 0 0 0