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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 Commission File Number 1-39270 Delaware ( State or other jurisdiction of incorporation or organization ) 10713 W. Sam Houston Pkwy N , Suite 800 , Houston , Texas ( Address of principal executive offices ) Title of Each Class Common Stock , $ 0.01 Par Value Preferred Stock Purchase Rights Patterson - UTI Energy , Inc. ( Exact name of registrant as specified in its charter ) to Registrant's telephone number , including area code : ( 281 ) 765-7100 Securities Registered Pursuant to Section 12 ( b ) of the Act : Trading Symbol PTEN 77064 ( Zip Code ) X 75-2504748 ( I.R.S. Employer Identification No. ) 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 or 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 or No No Name of Exchange on Which Registered The Nasdaq Global Select Market The Nasdaq Global Select Market 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 or No Accelerated filer Smaller reporting company Emerging growth company 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 . Large accelerated filer ooo Non - accelerated filer 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 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 Act ) . Yes No X The aggregate market value of the voting and non - voting common equity held by non - affiliates of the registrant as of June 30 , 2020 , the last business day of the registrant's most recently completed second fiscal quarter , was approximately $ 639 million , calculated by reference to the closing price of $ 3.47 for the common stock on the Nasdaq Global Select Market on that date . As of February 4 , 2021 , the registrant had outstanding 187,736,421 shares of common stock , $ 0.01 par value , its only class of common stock . Documents incorporated by reference : Portions of the registrant's definitive proxy statement for the 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this report .