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Table of Contents ☐ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ( 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 Large accelerated filer Non - accelerated filer Delaware ( State or Other Jurisdiction of Incorporation or Organization ) Title of Each Class Common Stock , par value $ 0.01 per share Form 10 - K 10 Post Office Square , Suite 1000 Boston , MA ( Address of Principal Executive Offices ) Albireo Pharma , Inc. ( Exact Name of Registrant as Specified in Its Charter ) П Commission File Number 001-33451 Registrant's telephone number , including area code ( 857 ) 254-5555 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) ALBO Securities registered pursuant to Section 12 ( g ) of the Act : None 90-0136863 ( I.R.S. Employer Identification No. ) 02109 ( Zip Code ) No No No Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes 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 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 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 Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S - K ( § 229.405 of this chapter ) is not contained herein , and will not be contained , to the best of registrant's knowledge , in definitive proxy or information statements incorporated by reference in Part III of this Form 10 - K or any amendment to this Form 10 - K . Name of Each Exchange on Which Registered The Nasdaq Capital Market Accelerated filer Smaller reporting company 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 . | X || 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 . 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 common stock of the registrant held by non - affiliates of the registrant ( without admitting that any person whose shares are not included in such calculation is an affiliate ) was approximately $ 394.2 million based on the price at which the common stock was last sold on The Nasdaq Capital Market as of the last business day of the registrant's most recently completed second fiscal quarter . The number of shares of the registrant's common stock outstanding as of February 18 , 2021 , was 19,113,603 . Documents Incorporated by Reference The following documents ( or parts thereof ) are incorporated by reference into the following parts of this Form 10 - K : Certain information required in Part III of this Annual Report on Form 10 - K is incorporated from the Registrant's Proxy Statement for its 2021 Annual Meeting of Stockholders to be filed with the Securities and Exchange Commission .