WBI Holdings, Inc. is an indirect wholly owned subsidiary of MDU Resources Group, Inc. and provides a key role in the corporation's diversified business strategy. This group of energy and energy service companies serve the upper Midwest and Central regions of the United States featuring natural gas pipeline, oil and natural gas production and exploration and energy services.

MDU Resources includes natural gas and oil production, construction materials and contracting, electric and natural gas utilities, natural gas pipelines and energy services, and utility services.