Mike Daniel, and shareholders representing 11.3% of NZX-issued capital, wrote to NZX chairman James Miller, asking the board and management to immediately reduce the cost base of the whole organisation.

Daniel, an investor and former Northland Port Corporation chairman, told Millar there seemed to be reluctance to accept that NZX faced little or no growth in revenue, while dealing with extremely high costs.

"The little or no growth comes at a time when the capital markets aroudn the world have been very positive, yet the NZX share price performance and total return is among the worst in the world for a listed stock exchange."

The NZX's strategic plan, targeting mid-term growth, and the Capital Markets 2029 review, aiming to boost listings, were not enough, he said.

Shareholders were still stuck with a declining share price.

"Endeavouring to retain present overhead levels while waiting for an outcome from the strategic plan and yet another review could easily see the NZX drop out of the NZX/S&P50 index, potentially negatively impacting the company's market capitalisation further."

He said a review was necessary, in light of the limited growth.

"Shareholders invest for earnings and the only way to increase earnings in the face of revenue stagnation is to reduce costs with renewed vigour."

He said "platitudes" would be insufficient. Shareholders expected "immediate and tangible" confirmation of efforts to "arrest the continued erosion of shareholder value".

"Should the NZX Board continue to ignore shareholders in this regard, as they seem to have largely ignored Elevation Capital's detailed NZXNOW presentation, the undersigned shareholders see little option but to effect change at the NZX Board level."

That would mean calling a special meeting to vote on board positions.

He did not disclose who the other shareholders were.

A spokeswoman for the NZX confirmed the letter had been received.

"We take shareholder concerns seriously, and our chair is in touch with Mike Daniel to discuss these concerns. We continue to be open to discuss any matter with all shareholders."

Late afternoon on Monday, shares were trading at $1.02, about 5% down on a year earlier.