The local Serco unit hasn't paid a dividend to its parent since the contract began. It paid tax of $207,186 last year.
"The parent company, Serco Group, has not been paid a dividend to date," a spokeswoman for the local unit said. "We have focused our resources on supporting our existing and future work in New Zealand. The parent company and other subsidiaries have been reimbursed for services provided."
In the latest performance assessment by Corrections, for the July-September quarter last year, Serco met almost 100 per cent of its performance measures. For the full-year, notes to Serco's accounts show a $174,136 Crown asset remediation provision.
Two prisoner escapes were recorded in the year, the second of a man who escaped from a health clinic during an eye check.
The Wiri prison was the first of the government's so-called public-private partnerships, or PPPs, where the private sector is allowed to invest in what has traditionally been a public sector role of providing health, education and other facilities.
Shares of Serco Group last traded at 592 pence on the London Stock Exchange and have gained about 9 per cent in the past year.