Who owns most of the oil refineries in the US?

As of my last knowledge update, the largest oil refineries in the United States are primarily owned by major oil companies and integrated energy firms. Notable owners include ExxonMobil, Chevron, and Phillips 66, along with other companies like Valero Energy and Marathon Petroleum. These companies operate extensive refining networks across the country, allowing them to process crude oil into various petroleum products. The ownership landscape can change due to mergers, acquisitions, and market dynamics.