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( Mark One ) 0 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 or 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 ) FORM 10 - K Title of each class Common Stock , Par value $ 0.001 per share Large accelerated filer Non - accelerated filer For the transition period from to Commission file number : 001-37557 Penumbra , Inc. ( Exact Name of Registrant as Specified in Its Charter ) X One Penumbra Place Alameda , CA 94502 ( Address of principal executive offices , including zip code ) O ( 510 ) 748-3200 ( Registrant's telephone number , including area code ) Securities registered pursuant of Section 12 ( b ) of the Act : Trading Symbol PEN Securities registered pursuant of 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 : x No : 0 05-0605598 ( I.R.S. Employer Identification No. ) 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 : 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 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 : x No : 0 Name of each exchange on which registered The New York Stock Exchange Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted and posted 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 : x No : 0 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 O 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 . O 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 . X Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes : □ No : x As of June 30 , 2020 , the aggregate market value of the registrant's common stock held by non - affiliates was approximately $ 6.0 billion , based on the closing price as reported on the New York Stock Exchange as of such date . As of February 9 , 2021 , the registrant had 36,448,693 shares of common stock , par value $ 0.001 per share , outstanding . DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's definitive proxy statement for its 2021 annual meeting of stockholders , which is to be filed not more than 120 days after the registrant's fiscal year ended December 31 , 2020 , are incorporated by reference into Part III of this Annual Report on Form 10 - K .