American Water Works Company, Inc. is a holding company for regulated and market-based subsidiaries throughout the United States and Ontario, Canada. The Company's Regulated Businesses segment provides water and wastewater services as public utilities in 16 states in the United States as of December 31, 2016. The Market-Based Businesses consists of four segments, including Military Services Group, which conducts operation and maintenance (O&M) of water and wastewater systems for military bases; Contract Operations Group, which conducts O&M of water and wastewater facilities for municipalities and the food and beverage industry; Homeowner Services Group, which primarily provides water and sewer line protection plans for homeowners, and Keystone, which provides water services for natural gas exploration and production companies. The Company, through its subsidiary, American Water Works Service Company, Inc. provides support and operational services for its operating subsidiaries.