The BT 500 survey ranks India's 500 most valuable private sector companies on the basis of average market capitalization. This rating does not include public sector undertaking companies.

The deciding metric in the ranking of the top 500 companies is their average market capitalisation on the Bombay Stock Exchange (BSE) for the first half of the current financial year—that is, the period between April 1 and September 30, 2007. Therefore, companies are ranked in order of their average market cap during that period. The reason BT has chosen average market cap over others as the deciding metric is simple: A company's market value is universally recognized as a variable that factors in not just present performance, but also future prospects.

For more details on the methodology visit: http://businesstoday.digitaltoday.in/index.php?issueid=15&id=2683&option=com_content&task=view