Difference between 2388 BOC (HK) && 3988 Bank of China

anyone can shared ? both share price difference quite a lot…

BOC HK is a subsidiary of BOC. Similar to OCBC NISP is a subsidiary of OCBC. Or Singtel OPTUS is a subsidiary of Singtel.
Essentially they are 2 different business entities. However I am sure that the performance of the subsidiary has an impact on the books of the parent company.

the business is focusing on the whole china for 3988.
the business is focusing on HONG KONG only for 2388.