The business has been sold to ASX listed telecommunications provider MNF Group Limited for AU$22.0 million.
Conclusion of the sale was contingent on receipt of U.S. government approvals and follows the completion of the sale of the non-U.S. business on 23 April 2015.
The acquisition will give MNF Group access to a global voice network spanning 4 continents and a portfolio of over 220 international carrier relationships and interconnect agreements.
Spark NZ reported a net profit of $148.1 million at 31 December 2015.