The stock exchange operator expects at least another half a dozen companies to list before the end of this year.
The listing last week of Genesis Energy completed the government's partial privatisation programme, which also included Meridian Energy, Mighty River Power and a sell-down of the government's stake in Air New Zealand.
NZX chief executive Tim Bennett said the Government's programme explains only about half of the exchange's growth of some $17 billion in the last 12 months.
The remainder of the rise in the market capitalisation is due to appreciation and six other listings including Z Energy, he said.
Mr Bennett expects most of the half-dozen companies that have appointed advisors to list within the next six months. The firms' valuations range from $50 million to $500 million, he said.
"We're seeing quite a large range of different types of companies listing, from agriculture to tourism, to transportation and of course the energy companies."
The head of equities at AMP Capital Investors, Guy Elliffe, says he knows of up to 10 firms considering a public listing.
He also expects more firms to consider acquisitions here and in Australia to boost earnings.