Bank of Communications, one of China's largest bank by assets, will join Hong Kong's benchmark Hang Seng Index from Sept. 10, the index compiler said Monday.

The addition will bring the total number of benchmark's constituent stocks to 40 from 39, and the number of H shares among them up to seven, with six of them being financial shares from the banking or insurance sectors.

Hang Seng Index Services Ltd, a wholly-owned subsidiary of the Hang Seng Bank, also announced changes in its index compilation method starting from Sept. 10.

Full free float adjustment will be applied to all HIS constituents and the capping level on individual weightings will be reduced to 15 percent from the current 20 percent, HSI Services Ltd said in its latest quarterly review released Monday.

The Bank of Communications, which analysts had expected to be included in the benchmark, is 18.6 percent owned by HSBC Holdings.

China CITIC Bank and China Molybdenum will join the H-share index, also from Sept. 10, increasing its membership to 43 firms from 41.

The primary business operations of China Molybdenum involve molybdenum mining, flotation, roasting and smelting, and downstream processing.