Commonwealth Bank has issued $US2.5 billion ($A3.6 billion) worth of subordinated notes.
A number of banks have issued them in recent months after the banking regulator told lenders they needed to bolster that type of capital, which acts as a buffer during a crisis.
Half the notes, priced at 3.61 per cent, are due 2034, with the remained priced at 3.743 per cent and due five years later.
AAP