ESRI was founded as Environmental Systems Research Institute in 1969 as a land-use consulting firm. ESRI products(particularly ArcGIS Desktop) have a one-third of the global market share, and are used by nearly 80 percent of GIS users worldwide from all professions.
ESRI has 10 regional offices in the U.S. and a network of 80 international distributors with about a million users in 200 countries. ESRI has 2,500 employees in the U.S., and is still privately-held by the founders. In 2006, year revenues were about $660 million. In 2008, ESRI ranked 70th on the list of largest software companies in the world. – Cont ΓÇô ESRI Wikipedia