匯豐銀行明智理財投資戶口問題

脹面結餘 is your existing amount
信貸總額 is the credit line that the bank offers you - if you have apply for the 'secured credit line' - usually when you open the account, there is a question on asking whether you want to have the secured credit line or not, then you will have a 信貸額 for you to use, you can read the below link for reference :
https://www.hsbc.com.hk/1/2/chinese/hk/loans/overdrafts/hp-pva-secured
https://www.hsbc.com.hk/1/2/chinese/hk/loans/overdrafts/hp-pva-secured/rates
可用結餘 is 脹面結餘 + 信貸總額
and if you purchase 股票, then the 股票 order will become and 'freezing amount' and also, if you have 信貸額, then the 股票 will have a certain percentage to sit on that, so, cannot really give you a actual figure now since you have not state clearly on the figures