DALLAS, Sept. 6, 2011 /PRNewswire/ -- Swank Capital, LLC and Cushing® MLP Asset Management, LP announced today that Atlas Pipeline Partners, L.P. (NYSE: APL) will replace Duncan Energy Partners L.P. (NYSE: DEP) after the close of trading on Wednesday, September 7, 2011. Atlas Pipeline Partners, L.P. is engaged in the gathering and processing of natural gas and the transportation of natural gas liquids in the Mid-Continent region of the United States. The Cushing® 30 MLP Index tracks the performance of 30 publicly traded MLP securities that hold midstream energy infrastructure assets in North America, chosen according to a proprietary fundamental scoring model developed by Cushing® MLP Asset Management, LP to rank potential MLPs for inclusion in the Index. The Cushing® 30 MLP Index is calculated by Standard & Poor's and reported on a real-time basis under the Bloomberg ticker "MLPX" and FactSet ticker "MLPX-CME". Expected MLPX Index Constituents: APL, ARLP, APU, BWP, BPL, CPNO, EPB, EEP, ETE, ETP, EPD, GEL, NRGY, KMP, MMP, MWE, NRP, NKA, NS, NSH, OKS, PAA, RGNC, SEP, SXL, NGLS, TCLP, TRGP, WES, WPZ. ABOUT SWANK CAPITAL AND CUSHING® MLP ASSET MANAGEMENT Cushing® MLP Asset Management, LP (" Cushing"), a subsidiary of Swank Capital, LLC, is an SEC-registered investment adviser headquartered in Dallas, Texas. Cushing serves as investment adviser to affiliated funds and managed accounts which invest primarily in securities of MLPs and other natural resource companies. Cushing is also the sponsor for The Cushing® MLP High Income Index which tracks the performance of 30 publicly traded energy and shipping MLP securities with an emphasis on current yield. The Cushing® MLP High Income Index is calculated by Standard & Poor's and reported under the Bloomberg ticker "MLPY" and FactSet ticker "MLPH-CME". Cushing continues to expand its platform of MLP-related investment products, leveraging extensive industry contacts and unparalleled research depth to drive both passive and actively managed investment opportunities for individual and institutional investors. Cushing seeks to identify and exploit investment niches it believes are generally less understood and less followed by the broader investor community. Contact:The Cushing® 30 MLP IndexFor additional information contact:214-692-6334 www.swankcapital.com The Cushing® 30 MLP Index (the "Index") is the exclusive property of Cushing MLP Asset Management, LP, which has contracted with Standard & Poor's to maintain and calculate the Index. Standard & Poor's® and S&P® are registered trademarks of Standard & Poor's Financial Services LLC. "Calculated by S&P Custom Indices" and its related stylized mark(s) are service marks of Standard & Poor's Financial Services LLC and have been licensed for use by Cushing MLP Asset Management, LP. S&P and its affiliates shall have no liability for any errors or omissions in calculating the Index.