CoStar Group Inc (NASDAQ: CSGP) is a commercial real estate information and marketplace company that provides data, analytics, and online marketplaces to real estate professionals and consumers. It makes money primarily through subscription-based access to its information and analytics platforms, and through marketplace advertising sold to property owners, landlords, and brokers. Its portfolio includes CoStar, the commercial real estate research platform, and the Apartments.com Network, a collection of rental listing sites including Apartments.com, ApartmentFinder, ForRent.com, AFTER55.com, CorporateHousing.com, ForRentUniversity.com, ApartmentHomeLiving.com, Apartamentos.com, WestsideRentals.com, and Off Campus Partners. The Apartments.com Network serves as the flagship consumer-facing residential rental marketplace. CoStar Group also holds a stake in Domain, an Australian real estate platform that operates an Agent Ownership Model providing real estate agencies an economic interest in Domain-affiliated entities.

Revenue model

Subscription fees for access to commercial real estate data and analytics platforms, and marketplace advertising fees paid by landlords, property managers, and brokers to list properties on the Apartments.com Network and related sites.

Products and services

CoStar (commercial real estate research and analytics platform), Apartments.com Network (Apartments.com, ApartmentFinder, ForRent.com, AFTER55.com, CorporateHousing.com, ForRentUniversity.com, ApartmentHomeLiving.com, Apartamentos.com, WestsideRentals.com, Off Campus Partners), Domain (Australian residential and commercial real estate marketplace with Agent Ownership Model structured equity vehicles).

Customers and end markets

Commercial real estate brokers, investors, lenders, and appraisers (CoStar platform); residential landlords, property managers, and apartment communities (Apartments.com Network); residential and commercial real estate agencies (Domain AOMs). End markets include commercial real estate transactions and leasing, residential rental housing, and real estate advertising.

Value-chain role

Data aggregator, analytics provider, and online marketplace operator sitting between property owners and brokers on one side and tenants, buyers, and real estate professionals on the other.

Geographic exposure

Primary operations in the United States; presence in Australia through Domain.

Source: SEC 10-K, filed 2026-02-26

Industry: Services-Business Services, NEC Peers: Booz Allen Hamilton Holding Corp Equifax Inc Jacobs Solutions Inc Leidos Holdings Inc Nielsen Holdings plc Verisk Analytics Inc TransUnion