The Commonwealth Bank has posted a full-year net profit of $9.23 billion, and its boss has defended CBA's decision not to pass on the full interest rate cut as better for the economy.

Key points: CBA's preferred cash profit measure up 3pc to $9.45b

CBA's preferred cash profit measure up 3pc to $9.45b Dividends to remain steady over the year at $4.20, fully-franked

Dividends to remain steady over the year at $4.20, fully-franked Bad loan costs jump 27 per cent

The bank's preferred measure of cash profit, which excludes a range of one-off and accounting items, was up 3 per cent to $9.45 billion.

The bank has copped flak from politicians, consumer groups and the media for failing to pass on the Reserve Bank's 25-basis-point interest rate cut in full.

However, CBA's chief executive Ian Narev said he had to balance the interests of the bank's stakeholders, not just for the institution's own sake but for the economy.

"As a result of our decision we will have depositors having an opportunity to earn more for their deposits, we've got borrowers paying less for their loans, we've got shareholders feeling more secure about their dividends," he told a press conference.

That's how you build confidence in the economy and create the stimulus that is going to increase growth.

CBA said its net interest income rose 7 per cent to $16.9 billion, despite a small fall in its net interest margin - the profitable gap between what rate the bank borrows money at and the rates it lends it out at - to 2.07 per cent.

However, as with ANZ's trading update yesterday, a significant 27 per cent jump in bad loan costs weighed on profits, although the bad loan write-offs remain just 0.19 per cent of CBA's total portfolio.

'Soft half from CBA'

It is a trend that many bank analysts have long forecast, with banks having profited from a reduction in bad debt provisions during the years after the global financial crisis.

The bank analysts at UBS said CommBank slightly missed average profit forecasts, but has managed to contain its business costs to offset weak revenue growth and the rise in bad debts.

"Soft half from CBA. Weak revenue trends across many divisions. Good to see a response on costs," the analysts wrote in a note.

But deteriorating asset quality trends are now clearly in place.

Shareholders certainly thought so, with the bank's shares down 1.3 per cent at $77.40 by the close of trade, as opposed to another 1.2 per cent gain for ANZ which released a well-received trading update yesterday.

Deposits to surge by 'a billion dollars a week'

Even before CommBank's move to increase term deposit rates after the RBA's interest rate cut earlier this month, CBA had grown its deposit base by 8 per cent over the past year to $518 billion, which is 66 per cent of the funding it needs.

Mr Narev today revealed the extent to which it expects deposits to surge due to the rate rise.

"Based on previous experience we would expect upwards of a billion dollars a week to come into these deposit products," he told the media briefing.

Despite the very public scandals that have rocked the Commonwealth Bank's financial planning and insurance arms, CBA's chief executive Ian Narev said the institution held top place for customer satisfaction.

"Customer satisfaction is the key metric we use to benchmark execution of group strategy, because satisfied customers look to us to meet more of their needs," he explained in a statement.

"This year we have achieved our best ever customer satisfaction results, and this has again translated into increased customer activity."

The bank has announced a fully-franked final dividend of $2.22 per share, leaving the full-year shareholder payouts flat on the previous year at $4.20.