Huang Jinbao is a gold trading tool designed and provided by Bank of China for domestic residents and non-residents involved in gold trading. When "Huang Jinbao" customers buy and sell gold in China Bank, all the traded gold will be credited to the gold passbook account opened by their customers in advance by the bank, and the money will be received and paid in the designated RMB deposit account or foreign exchange deposit account. The gold passbook issued by the bank will be used as the property right certificate for investors to hold gold. Therefore, "Huang Jinbao" business is essentially a paper gold transaction.
Because the bank does not directly collect cash or deliver gold in kind during the transaction, the gold in the customer's gold account can only be bought and sold, and cannot be extracted and stored.
I found it online, please have a look ~ I hope it helps.