If one of the goals of its partial asset sales programme is to try to get ordinary New Zealanders interested in the sharemarket again, this week has been a good one for the Government.
State Owned Enterprises (SOE) Minister Tony Ryall held the same portfolio between 1997 and 1999, during which time he oversaw the privatisation of Auckland International Airport and Capital Properties in 1998 as well as the Contact float.
He says the conversion rate or proportion of would-be Contact investors who actually went on to buy shares was pretty high, with about 225,000 ending up with shares.
Though the likely level of final demand for Mighty River shares from individual investors is something Mr Ryall is prevented by law from talking about, the early signs are that the Mighty River sale will eclipse that of Contact, which remains New Zealand's largest-ever share offer by investor numbers.
Mr Gaynor has no doubts. "This will be the largest participatory initial public offer [IPO] we've ever had in this country. I'd say it will be quite a bigger one than Contact Energy - probably 250,000 to 300,000 shareholders, which is a phenomenal figure given there is actually huge opposition to it.
"I think the amount of shareholders will actually exceed the amount of people who sign the petition opposing it."
There are easy comparisons to be made between the two offers - they are of similar size. After selling 40 per cent of Contact to US company Edison Mission, the Government of the day sold the remaining 60 per cent to retail and institutional investors for $1.1 billion or $1.5 billion in today's money.
The current valuation of the 49 per cent stake in Mighty River being readied for sale is about $1.8 billion.
Labour's SOE spokesman Clayton Cosgrove likes the comparison, saying that 14 years after it was listed, "we now know Contact is conservatively estimated to be 65 to 75 per cent foreign-owned and we know, of course, the National Party lost the election the year it floated it".
But according to 2011 Treasury advice to the Government, a further 30 per cent of Contact's shares apart from the Edison Mission stake was sold to overseas buyers. That means that if Mr Cosgrove's estimate is correct, foreign ownership of Contact's shares has only marginally increased and may in fact have fallen since 1999.
Nevertheless, Mr Ryall accepts that the number of ordinary New Zealand investors with Contact shares has slipped from the 225,000 immediately after the float to less than 80,000 today.
"Obviously a lot of people decided they wanted to take the gain. Some of those shares were bought by New Zealanders; some of them might have been bought by foreigners but look, it was a different time."
National has learned its lessons well from previous privatisations, particularly those done in the 80s and early 90s, which Mr Ryall says were done "holus bolus" and often with the sole objective of getting the best price for taxpayers, which generally meant selling assets to foreign owners. He says the current National Government would never have been able to get a mandate for asset sales it believed were necessary to control debt, "without being able to give an assurance that those businesses were going to be retained in majority Government ownership, and that's all there is to it and that's why we're so upfront about it".
So rather than Contact, Mr Ryall prefers to compare the Mighty River sale model to the privatisation of the Port of Tauranga in 1992, where the Bay of Plenty Regional Authority retained a 55 per cent stake and still does to this day.
"It's quite different to what we had previously because it really deals with the fact we're maintaining guaranteed New Zealand ownership 51 per cent as a minimum and we certainly know from the Port of Tauranga that in fact it's the New Zealanders now buying out the foreigners on their share register."
Mr Gaynor is a strong supporter of that "mixed ownership model" appropriated by the Government for the privatisation programme, saying Port of Tauranga had thrived under that arrangement against most expectations at the time.
"The ones we know of like Port of Tauranga, Ports of Auckland when it was listed and Air New Zealand have performed very well. The evidence in this part of the world is that model actually works quite well."
Even Auckland Airport, where Auckland Council retained a cornerstone or large minority shareholding, rather than a controlling stake, showed the strength of the model, Mr Gaynor said.
"I haven't seen any disasters under this model, whereas under 100 per cent privatisations we've had a ton of disasters."
Similarly, Solid Energy's recent problems underlined the potential problems under 100 per cent state ownership.
Nevertheless, Mr Cosgrove insists eventual foreign control of Mighty River is "a given" and suggests a future National Government will alter legislation to allow a further sell-down.
He also puts the rush of potential investors down to the "free money" on offer in the form of the loyalty bonus the Government has promised.
The scheme, available only to ordinary New Zealand investors, is likely to be similar to that offered to investors in the 2010 Queensland Rail float. Individual investors received an extra share after 12 months for every 15 they bought in the initial offer and held on to.
Mr Ryall said the scheme was part of putting New Zealanders "at the front of the queue ... and also part of sending a signal that we want New Zealanders to be longer-term investors in the sharemarket as an alternative form of people's savings".
But Mr Cosgrove criticised the scheme as a transfer of wealth from the Government and taxpayer to a relatively small group of New Zealanders.
"All the people who can't afford the one or two thousand bucks worth of shares will pay for the loyalty bonus that will be given to those people who can. There's no such thing as free money, somebody ends up paying and that's discounted out of the return that the Crown as the shareholder will get."
Mr Cosgrove suggests many individual investors will sell their Mighty River shares as soon as they get the bonus shares to make a relatively quick profit, but Mr Ryall said the Labour party was saying "you can't trust New Zealanders, they'll sell out the moment they get an opportunity". "I'm saying well it's quite the opposite with the Port of Tauranga where the Kiwis are buying out the overseas people."
Mr Gaynor, who has for years advocated the virtues of increased public participation in the sharemarket, hopes investors look at the share offer "realistically".
"It's not a get-rich-quick scheme, it's a good company and it should deliver a good solid return for a low-risk-type operation over the long term."
All a matter of dollars and sense
Retired Hamilton couple Rob and Ellen (not their real names) are exactly the type of long-term retail investors the Government hopes will buy Mighty River shares.
They have pre-registered for the offer and will possibly buy as much as $5000 worth each if they can, depending on what they see in the offer documents.
Rob told the Weekend Herald they buy as many long-term investments as they are able.
"We are not share traders. Other than takeovers we seldom ever sell. When we can, we put savings into the NZX and ASX markets. Nothing scientific; mostly simple common sense; some failures but more successes."
The couple bought 1612 Contact shares in the May 1999 public offer for $3.10 each or just under $5000 for the lot. Two years later they bought a further 9000 at $2.84 each or $25,5680.
From 2009 Contact started issuing shares instead of paying a cash dividend, which increased the couple's stake as did a 2011 "cash issue" of shares.
The couple now have 14058 Contact shares which were trading at $5.44 yesterday, giving their holding a value of $76,475 from their original combined investment of about $30,500.
Rob says they also received cash dividends from the date of the original investment until 2009 but is unsure what the total was.
He's reluctant to compare the returns from the couple's Contact investment with what they might have earned from money in the bank, but "turning a $30,000 investment into $75,000 plus over 13 years seems quite good to me ... I doubt that any bank could compete with that".
The comparison with bank returns misses the point but is a common blind spot among New Zealand investors, he says.
"Astute share investors are less interested in dividends than they are in capital growth. The best companies in growth industries keep most of their profits to help fund future expansion. The shareholders who invest in those companies are usually there for the long-term capital growth."
In fact since day one, Contact has given shareholders a total return, including share price gains and dividends, of 10.5 per cent per annum on average.
Rob bristles at Labour's claims that retail investors in privatised SOEs will sell out to foreign interests. "New Zealand shareholders are a bit smarter than Labour is prepared to admit. They don't sell out to overseas buyers unless the price is very high. Then when the overseas buyers realise they have paid too much we can buy the shares back at a much lower price."