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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 Delaware ( State or other jurisdiction of incorporation ) FORM 8 - K CURRENT REPORT Pursuant to Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 Date of Report ( Date of earliest event reported ) : May 13 , 2021 Silverback Therapeutics , Inc. ( Exact name of registrant as specified in its charter ) 001-39756 ( Commission File Number ) 500 Fairview Ave N , Suite 600 Seattle , Washington ( Address of principal executive offices ) Registrant's telephone number , including area code : ( 206 ) 456-2900 N / A ( Former name or former address , if changed since last report . ) 81-1489190 ( IRS Employer Identification No. ) 98109 ( Zip Code ) Check the appropriate box below if the Form 8 - K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions : Written communications pursuant to Rule 425 under the Securities Act ( 17 CFR 230.425 ) Soliciting material pursuant to Rule 14a - 12 under the Exchange Act ( 17 CFR 240.14a - 12 ) Pre - commencement communications pursuant to Rule 14d - 2 ( b ) under the Exchange Act ( 17 CFR 240.14d - 2 ( b ) ) Pre - commencement communications pursuant to Rule 13e - 4 ( c ) under the Exchange Act ( 17 CFR 240.13e - 4 ( c ) ) Securities registered pursuant to Section 12 ( b ) of the Act : Title of each class Common Stock , $ 0.0001 par value per share Trading Symbol ( s ) SBTX Name of each exchange on which registered The Nasdaq Stock Market LLC Indicate by check mark whether the registrant is an emerging growth company as defined in as defined in Rule 405 of the Securities Act of 1933 ( §230.405 of this chapter ) or Rule 12b - 2 of the Securities Exchange Act of 1934 ( §240.12b - 2 of this chapter ) . Emerging growth company ☑