CoStar Group, Inc. engages in the provision of online real estate marketplaces, information, and analytics in the commercial and residential property markets. It operates through the North America and International geographical segments. The North America segment includes the United States and Canada. The International segment refers to Europe, Asia-Pacific, and Latin America. The company was founded by Andrew C. Florance and Michael R. Klein in 1987 and is headquartered in Arlington, VA.