Big four pocket billions from borrowers

When the latest interest rate cuts come into effect, the big four banks will each have held back 0.37 percentage points of the Reserve Bank's 2.50 percentage points in cash rate drops, on average, from their standard variable interest rates.

NAB kept more of the cash rate cuts than the other three big banks since November 2011, according to the comparison website, with 0.46 percentage points.

The bank was followed by Commonwealth Bank and Westpac, both keeping 0.34 percentage points, while ANZ passed on the most out of the big four, keeping 0.33 percentage points.

Westpac has the highest standard variable interest rate of the big four banks, and this will be 5.70 per cent from February 20.

CBA has the second-highest of the big four, with a 5.65 per cent standard variable rate, also from February 20, while ANZ and NAB follow with 5.63 per cent from February 12 and 20 respectively.

Finder.com.au spokesperson Michelle Hutchison said a majority of Australian mortgage holders will be impacted by the big four banks’ decisions to keep rate cuts from customers.

"The big four banks hold 84 per cent of home loan market share of all banks monitored by the Australian Prudential Regulation Authority,” Ms Hutchison said, “and it's estimated that 70 per cent of all mortgage holders have a variable home loan.

"So when the big four banks hold out on passing on rate cuts, it's going to hit most households with a mortgage."