Tournament chairman John Hart confirmed it was "a significant loss".
Cushioning the blow, Millbrook, which also underwrites the Open, has committed to cover any loss.
Mr Hart would not confirm how much Sky’s sponsorship was worth, but they had been a naming sponsor — "the NZ Open presented by Sky Sport" — since 2020.
He said they had "scrambled" to try to fill the hole Sky had left.
"We’re not out of the woods — we won’t make money, we’ll lose money."
However, he said he could not praise enough Millbrook’s support as the tournament’s underwriter, "because most people would have said ‘no"’.
"When I took them through the rationale and where we were with what we were losing, not once did they falter."
He said Millbrook managing director Gota Ichii "looked at me and said, ‘John, we love what you’re doing, do your best, and we will cover the loss, whatever it is"’.
Mr Hart said there was no suggestion of reducing the prize money or lessening the experience.
Reflecting Millbrook’s commitment, the Open’s tag-line now is "presented by Millbrook".
Mr Hart said he understood Sky Sport’s position — "they’ve got their own model and they’ve got their own issues, but they are still our broadcaster and we’ve got a very good relationship with them".
"We’re meeting the production cost but they’re now paying for us to do the broadcast."
Sky NZ head of communications Ellie Brosnahan confirmed Sky was no longer a named sponsor "but remains highly involved in the NZ Open".
As to why it was no longer a named sponsor, she replied: "Sky partners with a large number of local and international sports codes to ensure we have a well-rounded array of sport on offer for our audiences.
"In that context, it’s normal for our partnerships to change in nature from time to time."
Ms Brosnahan said Sky had a long-standing relationship with the NZ Open and had just signed a new three-year agreement with the event as broadcast partner.
"We are also supporting the production partner for the event, NEP, through the Sky Sport graphics package and by providing Sky Sport presenters for the coverage."
She noted this year’s coverage, from 2.30pm each day, was available across Sky’s platforms, including, for the first time, full free-to-air coverage on Sky Open.
