MPLX LP, is a fee-based limited partnership formed by Marathon Petroleum Corporation to own, operate, develop and acquire crude oil, refined product and other hydrocarbon-based product pipelines and other midstream assets. The Company�s assets consist of a 51% indirect interest in a network of common carrier crude oil and product pipeline systems and associated storage assets in the Midwest and Gulf Coast regions of the United States. Effective March 1, 2014, MPLX LP, a majority-owned unit Marathon Petroleum Corp (MPC), raised its stake to 56%, from 51%, by acquiring a further 5%, in MPLX Pipe Holdings LP. Effective March 1, 2014, MPLX LP raised its stake to 69% from 56%, by acquiring a 13% stake, in MPLX Pipe Line Holdings LP.