X0101 EFFECT 33 LIVE 2014-01-02 14:00:00

S-4

0001489136 SemGroup Corp 333-193005 0001584018 SemCanada, L.P. 333-193005-12 0001584033 SemCanada II, L.P. 333-193005-11 0001584034 SemMaterials, L.P. 333-193005-10 0001584036 SemGroup Europe Holding, L.L.C. 333-193005-09 0001533324 SemOperating G.P., L.L.C. 333-193005-08 0001584037 SemMexico, L.L.C. 333-193005-07 0001584038 SemDevelopment, L.L.C. 333-193005-06 0001536485 Rose Rock Midstream Holdings, LLC 333-193005-05 0001584041 Wattenberg Holding, LLC 333-193005-04 0001584043 Glass Mountain Holding, LLC 333-193005-03 0001594623 Mid-America Midstream Gas Services, L.L.C. 333-193005-02 0001584016 SemGas, L.P. 333-193005-01