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Table of Contents ( 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 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 10 - K TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ACADIA HEALTHCARE COMPANY , INC . ( Exact Name of Registrant as Specified in Its Charter ) Title of each Class Common Stock , $ .01 par value Delaware ( State or other jurisdiction of incorporation or organization ) to Commission File Number : 001-35331 Large accelerated filer Non - accelerated filer 6100 Tower Circle , Suite 1000 Franklin , Tennessee 37067 ( Address , including zip code , of registrant's principal executive offices ) ( 615 ) 861-6000 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Name of exchange on which registered NASDAQ Global Select Market Securities registered pursuant to Section 12 ( g ) of the Act : None Symbol 45-2492228 ( I.R.S. Employer Identification No. ) ACHC No No 区 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 No 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 > Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a 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 . Emerging growth company If an emerging growth company , indicate by check mark of 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 . O 冈 Accelerated filer ■ Smaller reporting company 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 | As of June 30 , 2020 , the aggregate market value of the shares of common stock of the registrant held by non - affiliates was approximately $ 2.2 billion , based on the closing price of the registrant's common stock reported on the NASDAQ Global Select Market of $ 25.12 per share . As of February 26 , 2021 , there were 89,039,946 shares of the registrant's common stock outstanding . DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's definitive proxy statement for its 2021 annual meeting of stockholders to be held on May 6 , 2021 are incorporated by reference into Part III of this Form 10 - K .