The big four banks could be among the biggest beneficiaries of yesterday's RBA rate cut, according to new research.

An analysis from financial comparison site Mozo found the Commonwealth Bank is set to make an annual windfall of $334 million by only partial passing on the cut, while also pocketing $59.9 million by delaying the effective date of their cuts by 20 days.

At the same time, the NAB's partial cut could result in a potential $120.9 million gift horse and another $13.7 million by delaying the rate relief for 9 days.

At a glance:

• The RBA cut the national cash rate for the third time this year on Tuesday.
• New research from financial comparison site Mozo Big 4 banks’ tactic of holding back some of the RBA’s rate cuts has seen them pocket a $4.7 billion windfall since 2016.
• Mozo data shows that In July, 13 lenders passed on the RBA rate cut in full, while 63 passed on part of the cut. 

While the two other major banks are still to announce if they’ll cut rates, Mozo found by holding back some of the previous rate cuts ANZ is set to pocket $152.5 million a year and Westpac $127 million.

Mozo data shows that In July, 13 lenders passed on the RBA rate cut in full, while 63 passed on part of the cut.

Mozo Director Kirsty Lamont said that going forward, it was likely that the number of lenders passing on any official rate cut in full would decline. 

“The biggest lenders could soon be backed into a corner as the cash rate gets closer to zero,” she said. 

“With a potential fourth 25 basis point cut likely later this year or early 2020, the amount of money the big banks can earn in interest on loans compared to what they are paying to savers will get very tight. 

“Pressure on the big banks net interest margins, coupled with their higher cost structures, could soon make it uneconomical to cut home loan rates any further in a bid to keep up with the more efficient and competitive smaller lenders.” 

Similar to this:

RBA will keep close eye on housing market conditions in the coming months

Housing market could help balance out future risks for economy: RBA

Potentially more risk from not acting in today's market following RBA cut - Ray White Chairman Brian White