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Table of Contents ☑ UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON , D.C. 20549 FORM 10 - Q QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31 , 2021 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to ( Exact name of registrant as specified in its Commission file State or other jurisdiction of incorporation or charter ) number Crestwood Equity Partners LP 001-34664 organization Delaware Crestwood Midstream Partners LP 001-35377 Delaware 811 Main Street ( Address of principal executive offices ) Suite 3400 Houston Texas ( 832 ) 519-2200 ( Registrant's telephone number , including area code ) ( I.R.S. Employer Identification No. ) 43-1918951 20-1647837 77002 ( Zip code ) Securities registered pursuant to Section 12 ( b ) of the Act : Crestwood Equity Partners LP Crestwood Equity Partners LP Crestwood Midstream Partners LP Title of each class Common Units representing limited partnership interests Preferred Units representing limited partnership interests None Trading Symbol CEQP CEQP - P None Name of each exchange on which registered New York Stock Exchange New York Stock Exchange None 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 . Crestwood Equity Partners LP Crestwood Midstream Partners LP Yes Yes ☑ ☑ No ☐ No ☐ ( Explanatory Note : Crestwood Midstream Partners LP is currently a voluntary filer and is not subject to the filing requirements of the Securities Exchange Act of 1934. Although not subject to these filing requirements , Crestwood Midstream Partners LP 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 . ) Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site , if any , every Interactive Data File required to be submitted and posted 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 and post such files ) . Crestwood Equity Partners LP Crestwood Midstream Partners LP Yes Yes ☑ ☑ No ☐ No ☐