One thing is clear after three days of an inquiry into the big four banks - customers and politicians should give up expecting them to match interest rate cuts by the Reserve Bank.
The notion of passing on a rate change by the central bank is "essentially inaccurate", Westpac chief Brian Hartzer told a parliamentary committee on Thursday.
Earlier, National Australia Bank boss Andrew Thorburn explained to the House of Representatives economics committee that in a low interest rate environment, funding factors are having a greater influence.
While funding costs had fallen overall it wasn't by as much as the bank's lending rates, which translated to a reduction in bank margins.
"Put simply, banks are now earning less than they used to for every dollar they lend," he said.
The appearance of Mr Hartzer later on Thursday, wrapped up the three-day banking review inquiry.
Prime Minister Malcolm Turnbull demanded the big four banks face the committee at least once a year after they failed to pass on the last RBA rate cut in August.
It was his alternative to calls for a royal commission by Labor, the Greens and crossbench MPs and senators.
NAB appeared less keen to cut exorbitant interest rates on credit cards, unlike its competitor ANZ the day before which believed there was an opportunity to show leadership on the issue
"If customers only wanted a product based on price, every single customer that came to us today would take our low rate card," NAB chief operating officer Anthony Cahill told the hearing.
Only one third took NAB's low rate card while two-thirds preferred the premium products which attract a higher rate.
Later asked whether Westpac would still make a profit if it cut its credit card rates, Mr Hartzer replied: "We could, yes."
Like the heads of CBA and the ANZ, Mr Hartzer was quick to apologise for his bank's past wrong-doings.
He conceded a "trust-gap" has opened up in recent years between banks and customers and they needed to work harder to close it.
Mr Thorburn started his examination by telling the hearing how proud he was to be a banker and the bank's CEO.
"However, there have been some issues in our industry and at NAB, which we cannot be proud of," he admitted.
But it took a question 40 minutes into the hearing from Labor MP Matt Thistlethwaite, the committee's deputy chairman, to get Mr Thorburn to apologise.
"I have apologised and I do so again," Mr Thorburn responded.
Mr Thorburn, like other bank bosses, supported the proposal of a banking tribunal funded by the industry.
But Mr Hartzer was more guarded in his response.
There are already bodies customers can go to, like in superannuation and insurance, but if people are falling through the cracks, he supports the idea of reviewing the architecture of appeal.
"If the answer is a tribunal, so be it," he said.
"We would simple say, let's not just add another layer."
