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( Mark One ) UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year 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 Delaware ( State or Other Jurisdiction of Incorporation or Organization ) 6120 South Yale Avenue , Suite 805 Tulsa , Oklahoma ( Address of Principal Executive Offices ) Form 10 - K to Commission File Number : 001-35172 NGL Energy Partners LP ( Exact Name of Registrant as Specified in Its Charter ) Title of Each Class Common units representing Limited Partner Interests Fixed - to - floating rate cumulative redeemable perpetual preferred units Fixed - to - floating rate cumulative redeemable perpetual preferred units Large accelerated filer Non - accelerated filer ( 918 ) 481-1119 ( Registrant's Telephone Number , Including Area Code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbols NGL NGL - PB NGL - PC 27-3427920 0 0 ( 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 > 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 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 74136 ( Zip Code ) 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 Accelerated filer Smaller reporting company Name of Each Exchange on Which Registered New York Stock Exchange New York Stock Exchange New York Stock Exchange 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 . X 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 . 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 at September 30 , 2020 of the Common Units held by non - affiliates of the registrant , based on the reported closing price of the Common Units on the New York Stock Exchange on such date ( $ 3.96 per Common Unit ) was $ 344.6 million . For purposes of this computation , all executive officers , directors and 10 % beneficial owners of the registrant are deemed to be affiliates . Such a determination should not be deemed an admission that such executive officers , directors and 10 % beneficial owners are affiliates . At May 28 , 2021 , there were 129,593,939 common units issued and outstanding .