A number of different classification systems exist to assist portfolio managers in diversifying exposure to industry- or sector-specific risk.

The Industry Classification Benchmark (ICB) and the Global Industry Classification System (GICS) are very popular among practicioners. The two frameworks are reported to be similar in methodology and equivalent in use.

Keep in mind that differences do exist between the two systems. These differences, however, are concentrated around individual sectors and are the result of classification decisions inherent in the methodology. The two methodologies are therefore globally similar and locally different.