The Government has long said shares in Mighty River Power would be popular, but even the Treasury was caught out by the level of interest when the programme was launched.
A day after Tony Ryall expressed confidence in the ability of a dedicated website to process pre-registrations, the site buckled under pressure, hours before a $1.1 million advertising campaign was started.
Having been told to expect spikes in demand, servers were added by the Treasury, and Kiwis handed over their contact details, in their thousands.
"We're certainly pleasantly surprised on the upside," said John Crawford, the Treasury's head of commercial transactions, as the number of pre-registrations hit 151,978 at 5.15pm yesterday.
Since the launch on Tuesday morning, Kiwis had been lodging their interest at more than one a second, much faster than Contact Energy, the last major state sell-off, and even Queensland Rail, a larger sale in Australia in 2010.
"The world's changed in terms of media and how people respond quickly ...
"The vast majority of those pre-registrations were driven only by online news channels," Mr Crawford said.
Green Party co-leader Russel Norman said it was no surprise the level of interest was high, with political interest giving Mighty River's float unprecedented profile.
But the numbers were a tiny fraction of the adult population, and did nothing to dent the party's claim that three-quarters of New Zealanders still opposed the sales, he said.
"There's probably a significant number in that 100,000 who don't support asset sales but think 'if they're going to be sold anyway, I might as well do what I can to prevent the shares falling into foreign ownership'."
Some are indeed preparing to buy, in spite of their opposition.
Tauranga retiree Ron, who declined to give his last name, was one of dozens in a Fairfax-Ipsos poll who said last year that state asset sales were the major thing going wrong in New Zealand.
As opposed to the sales now as he was then, he still pre-registered for shares on Tuesday to help keep them in Kiwi hands.
"If they are going to be sold, it's better that I get my slice than some foreigners."
Having made the sales a flagship policy, the Government is now hypersensitive, blaming its approach on Securities Act concerns.
When a story emerged of a woman being contacted by a stock broker minutes after she left details by telephone with the Mighty River 0800 number, the Treasury insisted its systems had "bank level security".
A press statement from SOE Minister Tony Ryall, who was unavailable for interview, told media that its contents "are not permitted to be made available to persons" outside New Zealand.
Through a spokeswoman, Mr Ryall refused to say how much of the pre-registrations would turn into buyers, or how many they expected to sign up.
Meanwhile, officials have been busily taking down documents from the Treasury and Beehive websites which refer to the Mighty River offer, after legal advice.
"[We] have decided to take a very conservative approach now that we are into the pre-registration stage," a spokesman for Finance Minister Bill English said.