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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 For the fiscal year ended December 31 , 2020 . □ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to or Commission File Number : 001-36102 Knowles Corporation ( Exact name of registrant as specified in its charter ) Delaware ( State or other jurisdiction of incorporation or organization ) Title of each class Common stock , $ 0.01 par value per share 1151 Maplewood Drive , Itasca , IL ( Address of Principal Executive Offices ) 60143 ( Zip Code ) ( 630 ) 250-5100 ( Registrant's telephone number , including area code ) ( I.R.S. Employer Identification No. ) 90-1002689 Securities registered pursuant to Section 12 ( b ) of the Act : Trading symbol KN Name of each exchange on which registered New York Stock Exchange Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes > No No | Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Act . Yes □ 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 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