The Financial Markets Authority says its chief executive, Sean Hughes, will not seek reappointment for a second term and will leave the financial regulator at the end of the year.
Hughes, who led the FMA from its establishment three years ago, said it had been an intense and satisfying period of work.
"Having delivered on my primary task to design, build and implement the strategic and operational platform for FMA, I have decided to complete my contract this year, and look to identify my next challenge," he said. "Announcing my decision now will allow a smooth and orderly transition for the leadership of FMA's next stage."
Chairman Simon Allen said that while the FMA's board was disappointed that Hughes was departing, it respected his decision.
"We also recognise the significant work he has put into FMA's establishment and its positioning in both the domestic and Asia Pacific markets," Allen said.
He said Hughes had done an outstanding job of leading the regulator.
"Looking forward, FMA's regulatory scope is set to further expand from next year with the introduction of the Financial Markets Conduct Act," Allen said. "The timing is well aligned for the next chief executive to advance this work."
The FMA said it would use an external agency to help find Hughes' replacement.
An appointment is expected to be made by the end of the year.
The FMA is the single regulator for New Zealand's financial markets.
It took over regulatory functions previously carried out by the Securities Commission, Ministry of Economic Development and NZX.