Financial Markets Authority (FMA) executive Garth Stanish left the investment watchdog at the end of last month over an internal employment matter, a spokesman for the authority said.
"Because it is an internal employment matter, we can't provide any further comment," the spokesman said.
Stanish was the FMA's director of capital markets.
Before joining the FMA he was head of issuer regulation and an acting head of regulation at NZX.
He has previously held positions with Crown Law and Simpson Grierson Law.
In 2017, Stanish commented on conduct in the bank bill market in the wake of the High Court judgment against former fund manager Mark Warminger.
Stanish was also a director of markets oversight, a group that includes oversight of NZX, crowd-funding/P2P lending platforms and frontline supervisors.
The FMA was established in 2011 to take over the functions of the then Securities Commission.