X0202 3 2006-02-09 0 0001246263 MAGELLAN MIDSTREAM HOLDINGS LP MGG 0001349441 MGG Midstream Holdings, L.P. ONE WILLIAMS CENTER TULSA OK 74172 1 0 1 0 0001349464 MGG Midstream Holdings GP, LLC ONE WILLIAMS CENTER TULSA OK 74172 1 0 1 0 0001122443 MADISON DEARBORN CAPITAL PARTNERS IV LP 1 0 1 0 0001181100 MADISON DEARBORN PARTNERS LLC THREE FIRST NATIOANL PLAZA STE 3800 CHICAGO IL 60602 1 0 1 0 0001247497 RIVERSTONE HOLDINGS LLC 1 GREENWICH OFFICE PARK GREENWICH CT 06831 1 0 1 0 0001247527 CARLYLE RIVERSTONE ENERGY PARTNERS II LP 1 0 1 0 0001247529 C R ENERGY GP II LLC 1 0 1 0 0001247532 CARLYLE RIVERSTONE MLP HOLDINGS LP 1 0 1 0 0001249306 MADISON DEARBORN PARTNERS IV LP THREE FIRST NATIONAL PLAZA STE 3800 CHICAGO IL 60602 1 0 1 0 Limited partner interests Common Units representing limited partner interests 40646551 D These limited partner interests will convert to Common Units representing limited partner interests in the issuer upon the closing of the issuer's intial public offering on February 15, 2006. These limited partner interests are owned by MGG Midstream Holdings, L.P., which is a member of a "group" for purposes of Section 13(d) of the Exchange Act including MGG Midstream Holdings GP, LLC, Carlyle/Riverstone MLP Holdings, L.P., Carlyle/Riverstone Energy Partners II, L.P., C/R Energy GP II, LLC, Riverstone Holdings LLC, Madison Dearborn Capital Partners IV, L.P., Madison Dearboarn Partners IV, L.P., Madison Dearborn Partners, L.L.C., and other entities not jointly filing on this Form 3. The joint filers jointly are filing this Form 3 and information regarding the joint filers other than MGG Midstream Holdings, L.P. is set forth on Exhibit 99 to this Form 3. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interests therein, and this report shall not be deemed an admission that the reporting persons are beneficial owners of the reported securities for purposes of Section 16 or for any other purpose. Lonny E. Townsend, VP and General Counsel of MGG Midstream Holdings GP, LLC, general partner of MGG Midstream Holdings, L.P. 2006-02-09