40 Under 40 is a list compiled by Fortune magazine that includes persons that the newspaper judges to be the most prominent young leaders of the year. There have been two periods to the list's existence: To begin with, from 1999 to 2003, the list was provided just as a numerical ranking of wealth, which coincided with the beginning of the dot com bubble. The current iteration, which began in 2009 and is a subjective rating of power and influence, has been in use since then. The list covers corporate executives, political personalities, athletes, fashion designers, and others under the age of forty who are leaders in their respective fields. The bulk of the list's members are corporate leaders working in the technology sector, according to the list.
Candidates from blue chip sectors are not usually included on the list, which often includes businessmen and women who have established their reputations in a variety of other enterprises.