When major investors own shares in several firms in the same industry, the traditional approach to concentration measurement by the Hirschman--Herfindahl Index (HHI) fails to accurately reflect the level of competition in the market. To address this problem we derive a generalized HHI formula...

When major investors own shares in several firms in the same industry, the traditional approach to concentration measurement by the Hirschman-Herfindahl Index (HHI) fails to accurately reflect the level of competition in the market. To address this problem we derive a generalized HHI formula...