
The partnership is a master limited partnership (MLP), a creature of corporate finance that operates like a medieval guild crossed with a modern-day toll road. It was birthed by Marathon Petroleum, the refining giant, to own and operate midstream energy infrastructure-pipelines, processing plants, and storage terminals. Think of it as the postal service of the oil and gas world, delivering crude and natural gas liquids (NGLs) to their final destinations. The beauty of this business model is its reliance on long-term contracts and regulated rates, which provide a stability that would make a cat napping in a hammock envious.