NAB sold its auto leasing and two Asian insurance divisions this year to "focus on domestic operations," and a review of the credit card business' profitability is undergoing an internal review.
A spokesperson for NAB told an Australian newspaper that the rumours are just speculation and they were happy with the credit card division's performance.
The bank's market position is falling constantly, and reports the card division has lost a half per cent in the last six months of 2005.
Share price at the bank is also deteriorating, and Citicorp caused Friday's fall by re-evaluating its rating of NAB to "hold" from "buy."
NAB shares fell 14 cents to $37.55 on Friday's close.