Dow Jones Sustainability Index (DJSI) is the longest-running of its kind, built by Sustainability Asset Management (SAM) and Dow Jones Index in 1999. A family of different indexes, its goal focuses on providing a clear standard to investors interested in corporate performance around environmental, economic and social goals, increasingly regarded by many investors as key not only to  corporate social responsibility but also the creation of long-term value. The DJSI World  index evaluates the performance of the 2,500 largest companies from 58 different areas in 52 countries, whilst other indexes cover specific geographical regions.  This and indexes like it are seen as a key mechanism in encouraging firms to keep improving their sustainability performance.