The RBNZ's rate cut has given two banks the opportunity to boost margins, by reverting to standard industry levels and removing their rate benefits

Thursday's OCR cut brought a swift response from banks.

Because the cut was clearly signaled by the Reserve Bank, and widely expected by the markets, banks were ready with their rate adjustments.

A -25 basis points policy rate cut has basically flowed through to a -25 basis points cut in bank floating rates.

Except that a few banks decided to pocket some of it and passed on less than the full policy cut.

Here is a summary of the changes they have announced:

Standing out in this list are the changes by both BNZ and Westpac. Both have decided no not pass all of the cut on to their customers.

BNZ is only passing on 10 bps of the benefit to its Total Money clients.

Westpac is passing on only 15 bps.

The new Westpac rate brings them back basically matching ANZ and ASB.

Westpac has form. Prior to the June 11 OCR reduction, Westpac's floating rate was 6.59%. They then only passed on 19 bps of that 25 bps OCR reduction.

Only July 23, Westpac passed on the full 25 bps reduction, matching the RBNZ's OCR cut.

And this time the Red Bank has kept more, again.

This means over the past three OCR cuts Westpac has kept 16 bps to bolster margins - paid for by their customers.

BNZ has defended their reduced response by focusing on their Total Money product's way of applying interest. They want you to think of "effective interest" - where the carded rate is applied to a loan balance reduced by qualifying deposits.

And even after the smaller reduction, the new carded rate is still the lowest in the market, but now equal with SBS Bank's offer.