It comes after it pushed back on a proposal by a top shareholder to split the lender.
HSBC said the idea put forward by China's Ping An Insurance Group would be costly.
It also argued it could hurt the bank's credit rating, tax bill and operating costs in the long-term.
Monday's comments were the most direct defense by Europe's biggest bank against the move.
In April, Ping An had called to carve out the lender's Asian operations.
HSBC is due to meet shareholders in Hong Kong on Tuesday (August 2) to talk over the insurer's idea.
The bank also pleased investors by posting profits beyond expectations.
HSBC saw a pretax profit of $9.2 billion for the first half of the year.
It was down from last year, but beat analyst estimates of around $8.1 billion.
The lender said it would now focus on restructuring its U.S. and European businesses instead of a break-up.
HSBC also vowed to go back to paying quarterly dividends from early next year.