The bank shareholders of Paymark have entered into an agreement to sell the company to Ingenico Group for $190 million.
ANZ, ASB, BNZ and Westpac each own 25 per cent of the shares in Paymark.
The Auckland-based specialist electronic transaction processing company handles a high proportion of New Zealand's debit and credit card transactions through its switching infrastructure.
Switching is the process that connects a customer's card used at a merchant terminal with the bank or other institution that issued them the card.
Ingenico Group is listed on the Paris Stock Exchange and has extensive operations in the payments industry across 170 countries. Ingenico's payment terminals are widely used in New Zealand.
The sale agreement is conditional on receiving Commerce Commission and Overseas Investment Office approvals.
The shareholders said they believed Ingenico would be a good owner for Paymark as it was a specialist in the payments business internationally and would be able to bring a high degree of technical skill and innovation to an increasingly complex and creative industry.
Paymark processes more than 75 per cent of the New Zealand's electronic card transactions.
About $5.9 billion was spent through Paymark's network in December, up 4.9 per cent on the same month in 2016. Underlying spending was up 0.5 per cent on November, Paymark said.
Spending through Paymark last year totalled $60b - up 5.4 per cent on 2016. This was slightly below the 5.8 per cent average annual growth of the past five years.