ABC Supply Co., Inc. is a major, private American roofing supply company based in Beloit, Wisconsin. It also sells windows, gutters, and siding for residential and commercial buildings and is the largest roofing and vinyl siding wholesale distributor in the United States. The company was founded in 1982 by Ken Hendricks and Diane Hendricks. It grew from a single store in Wisconsin to having over 490 branches in 49 states nationwide. ABC Supply has expanded from its original business. In early 2010, the company acquired Bradco Supply, its largest acquisition to date.