The bank's two representatives on the TCNZA board have also resigned.
Telecom New Zealand signed the five-year deal with the CBA in August 2000. The then head of the CBA's technology, operations and property business unit, Russell Scrimshaw, said TCNZA would "utilise the expertise of AAPT, ComTech [now Dimension Data] and EDS" in "streamlining the CBA's existing telecommunications infrastructure into a single Internet protocol network supporting a full range of integrated data, voice and video services".
Under the original deal, the CBA had an option to take a stake of up to 35 percent in TCNZA within five years.
Telecom New Zealand group spokesperson Andrew Bristol emphasised that the relationship with CBA was "unchanged" even after the buyback. He told ZDNet Australia that the CBA's option to take a stake of up to 35 percent in TCNZA lapsed on 30 June, 2003.
"The bank didn't take up that option and so it had already lapsed since the option had to be taken up within a finite time," Bristol said.
Bristol said the telecommunications company paid the same nominal price for the 5 percent stake as the bank did when it acquired the stake in August 2000 as part of the telecommunications outsourcing arrangements.
Mark Ratcliffe, Telecom NZ chief executive officer and group general manager ICT services, said when the bank took the stake, it was "not uncommon for customers to take an interest in their outsourcing partners to help ensure that both organisations were aligned around contract performance and delivery".
"Four years on, TCNZA has built up a strong relationship with the [CBA] and has a deep understanding of the bank's business. In the circumstances, all involved felt it no longer necessary for the bank to have a stake in TCNZA," Ratcliffe said.
Bristol added that TCNZA was already in discussion with the CBA regarding its future relationship with the financial heavyweight after the initial contract expires in September next year.