The four biggest banks have kept most of the net benefits of the interest rate cut announced by the Reserve Bank of Australia. The same can be assessed from the constant movements in the interest rates of credit cards.

The four banks in question are- Westpac, ANZ, CBA and NBA.

And since the figures show that the net impact of the rate cut on the banks have declined, it is not surprising that they were able to keep as much as 85 per cent of the net benefit.

In March 2008, the net impact of rate cut was at 7.25 per cent. And since then it has fallen down to 3.5 per cent.

The data collected by a website named RateCity has shown that while the banks did pass on the benefits to the customers, the four biggest banks managed to keep the lion's share of the increase with themselves.

This they were able to do by charging higher from the credit card borrowers.

RBA had reduced the rates by 3.5 per cent.

While Westpac has said that it would pass on the charges to credit card customers, others said that they have not thought about it as of yet.