The Commerce Commission has warned two banks about the formula they used to calculate mortgage break fees.
The commission began investigating fees that banks charged customers if they repaid their fixed-rate loans early after complaints from customers in 2008 and 2009 when interest rates dropped.
The commission concluded that all the banks under investigation were found to have charged reasonable fees. They were: ASB, SBS, BNZ, National, KiwiBank, HSBC, Westpac, ANZ and GE.
However, the commission has warned KiwiBank and HSBC that the way they calculated the break fee was technically wrong.
As a result, KiwiBank has repaid $689,000 to customers and HSBC has repaid $113,000.
The commission says they have since changed their formula.