Wisconsin Public Service Corporation, a wholly owned subsidiary of Integrys Energy Group, Inc. (NYSE:TEG) , is an investor-owned electric and natural gas utility headquartered in Green Bay, Wisconsin. It serves approximately 420,000 electric customers and 309,000 retail natural gas customers in residential, agricultural, industrial, and commercial markets, as well as wholesale customers. The company's service area includes northeastern and central Wisconsin, as well as an adjacent portion of Upper Michigan.