NZX has swiftly replaced Geoff Brown, with Fiona Mackenzie named as the new head of markets.

Mr Brown – who had been with the NZX for eight years – abruptly retired on Wednesday, with no explanation given for his sudden departure.

NZX has wasted no time in appointing Ms Mackenzie, who has been head of liquidity and traded products for the past year, as his replacement as head of markets.

Geoff Brown, head of market products at NZX, has resigned from the role after eight years with the company.

In a brief statement made this afternoon, NZX said Mr Brown’s resignation was effective from today.

While the NZX did not give any reason for his departure, it said Mr Brown had been a “tireless advocate” for New Zealand companies and an “energetic proponent” of the country’s markets.

It also said his imprint on the first critical phases of NZX’s growth has been considerable.

Shares in NZX Limited have taken a hit on the company’s own exchange today after it slashed $19.9 million from the expected sale proceeds of its carbon trading business.

At 3pm NZX shares were down 13c at $2.05, a fall of 6%, on mild volume.

Late on Friday, after the market closed, NZX announced it would write down the carrying value of remaining sale proceeds of its TZ1 Registry, which it sold to UK firm Markit Group last year.