Rather than using a fixed number of large cap or small cap stocks, Morningstar uses a flexible system that isn't adversely affected by overall movements in the market. Stocks are divided into seven style zones based on their country of domicile (Africa stocks are included in the Europe style zone). Within each zone, the market cap of each stock is converted to a common currency, the stocks are organized in descending order by size, and the cumulative capitalization as a percentage of total sample capitalization is calculated for each stock. Giant-cap stocks are defined as the group that accounts for the top 40% of the capitalization of the style zone; large-cap stocks represent the next 30%; mid-cap stocks represent the next 20%; and small-cap stocks represent the balance. For the traditional Style Box, giant-cap stocks are included in the large-cap group.
Click here to view the breakpoints. Note: market caps are the minimum in each cap group; therefore, the minimum large market cap is the large-medium breakpoint and medium is the medium-small breakpoint.