CoStar Group, Inc. is a company that specializes in offering information, analytics, and marketplace services to professionals from the commercial real estate, hospitality, residential, and related industries. The company offers several tools and platforms such as CoStar Property, CoStar COMPS, CoStar Market Analytics, CoStar Tenant, and many others that help professionals in their line of work. CoStar Group, Inc. also operates several apartment marketing sites, online auction platforms, and a software platform for homes for sale listings.