The fact it would now operate under the scrutiny of the Government which retains a 51 per cent stake and retail and professional investors meant "the incentives to manage the business well will be sharper than ever".
Ryall also took a swipe at Labour and the Greens whose proposal for electricity market reform is blamed for affecting demand for shares in Meridian and Mighty River Power which was partially floated in May.
"In spite of the best efforts of some, the Government is very proud that Meridian is now on the market."
Meridian chief executive Mark Binns thanked his staff who had been working for 18 months on what was the largest ever IPO in New Zealand.
That work was conducted in a politically charged environment and against the backdrop of discussions about the future of the Meridian's largest customer, the Tiwai Point aluminium smelter.
Throughout that, Meridian's team `stayed on song in terms of delivering for customers and ensuring the underlying business continues to improve".
Investors now had a stake in some of New Zealand's "most iconic infrastructure assets" and Binns said he had no doubt that the additional transparency and reporting requirements that came with listing would lead to "better decisions and better governance".