Joost van Amelsfort, NZX head of market supervision, said the high number of investigations reflected its focus on continuous disclosure.
But while investigations had gone up, breaches had gone down.
"That shows the benefit of engagement with the market we are having."
Van Amelsfort said the report was designed to help improve the visibility about what the NZX does through its regulatory arm.
The NZX releases it regulatory metrics throughout the year and must give an annual report to the Markets Disciplinary Tribunal.
But van Amelsfort said this report was about giving market players more insight into how its enforcement team worked.
The report noted the NZX's regulatory arm would this year focus be on the timing of announcements, the treatment of developing information and how issuers manage market expectations.