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☐ 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 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to COMMISSION FILE NUMBER 001-35633 Sound Financial Bancorp , Inc. ( Exact Name of Registrant as Specified in its Charter ) Maryland ( State or other jurisdiction of incorporation or organization ) 2400 3rd Avenue , Suite 150 , Seattle , Washington ( Address of principal executive offices ) 45-5188530 ( I.R.S. Employer Identification No. ) 98121 ( Zip Code ) Registrant's telephone number , including area code : ( 206 ) 448-0884 Securities registered pursuant to Section 12 ( b ) of the Act : Title of each class Trading Symbol ( s ) Common Stock , par value $ 0.01 per share SFBC Name of each exchange on which registered The NASDAQ Stock Market LLC Securities Registered Pursuant to Section 12 ( g ) of the Act : None Indicate by checkmark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No ☑ Indicate by checkmark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes □ No Indicate by checkmark 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 □ Indicate by checkmark 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 □