A sector is a grouping of companies based on common business type (e.g. car manufaturers, or aerospace companies). In Calcbench, we use the company's self reported SIC (standard industrial classification) code in order to determine its sector.
To look at companies by sector you can:
1) Navigate the sector tree by first selecting an industry, and then choosing a sector that belongs to that industry
2) Search for a sector by name OR 4 digit SIC code or 6 digit NAICS code using the 'Search Sector' box
3) Choose a company in the 'Find Peers For' box to bring up that company's sector