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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 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 : 001-38456 COLUMBIA FINANCIAL , INC . ( Exact name of registrant as specified in its charter ) Delaware ( State or other jurisdiction of incorporation or organization ) 19-01 Route 208 North , Fair Lawn , New Jersey ( Address of principal executive offices ) 22-3504946 ( I.R.S. Employer Identification No ) 07410 ( Zip Code ) ( 800 ) 522-4167 Title of each class ( Registrant's telephone number , including area code ) Securities Registered Pursuant to Section 12 ( b ) of the Act : Common stock , par value $ 0.01 per share Trading symbol ( s ) CLBK Name of exchange on which registered The Nasdaq Stock Market LLC Securities Registered Pursuant to 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 □ 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 > No 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 during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) : * Yes No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , 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 . Large accelerated filer ☑ Non - accelerated filer П Emerging growth company ☐ Accelerated filer Smaller Reporting 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 . □ Indicate by check mark whether the registrant has filed a report on and attestation to its managements'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 . ☑ Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Exchange Act ) . ■ Yes > No The aggregate market value of the voting and non - voting common equity held by non - affiliates as of June 30 , 2020 was $ 582.8 million . The number of shares outstanding of the registrant's common stock as of February 19 , 2021 was 109,673,314 . DOCUMENTS INCORPORATED BY REFERENCE Portions of the Registrant's Proxy Statement for the 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this Form 10 - K .