David May remembers the early days of the New Zealand Superannuation Fund - it had no office, no staff and $2 billion in the bank.
As the first chair of the fund - which has now grown to $58 billion - May had the job of hiring its first chief executive, Paul Costello, and setting up all its systems and processes.
"It was a far cry from what it is today. We started off with no staff. No premises. We had $2 billion sitting in the bank. We had pretty demanding legislation; it said we had to be best-practice in the world - we had no idea what that meant."
Set up in 2001 by the Helen Clark-led Labour Government, the fund was the brainchild of Finance Minister Michael Cullen, as a way to put aside some money to help pay for the future costs of New Zealand Superannuation.
It didn't begin investing until 2003. Tim Mitchell, the first employee at the fund, believed it would just be a short-term gig to help it get going.
"I thought this sounds like a good six-months-to-one-year gig to go help and set up." He ended up being there 13 years.
The board had to borrow a room from the Government Superannuation Fund for meetings and a staff member to be secretary.
"They had no bank account, no stationery," Mitchell recalls.
"In the very early days it was that start-up feel, everyone had to pitch in and do everything because there was so much to be done to get the show on the road."
Originally based in Wellington, there was debate about moving the fund to Auckland where it is now based to ensure it was run at arm's length from government and political interference.
That only went so far; John Key's National-led Government put a hold on contributions and there was pressure from politicians to invest more of the fund in New Zealand.
It has also had to stand up against two major market meltdowns - the first during the global financial crisis in 2008 and then last year in March when global markets dropped because of Covid.
Matt Whineray, the current chief executive of the fund, said when it was hit by the GFC it was much smaller in size than last year, when its value fell by $9b in a matter of months.
Since then it has regained all of that and more, making a record 29 per cent return in the year to June 30.
"If you take it back to early March last year when things were falling 2 or 3 per cent a day, you don't know where the end of that is. It is much easier to say 'I can survive this if I know where the bottom of the drop is' but of course you don't."
But what the fund did do was prepare the Government and the public for a potential big drop by warning that such things could happen and modelling the situation in a 2018 annual report.
"What we were trying to do with that is say we can live through that. We have set ourselves up to manage the liquidity, respond to volatility but what we can't live through is someone taking the keys off us.
"Sometimes you get this question of where is your stop-loss for this strategy? And my answer to that is if you have stopped, you have lost."
When the fund did the modelling based on the GFC losses, it also warned that the market downturn could be much more prolonged.
"Actually the bounce we saw last year happened much faster [than the GFC]. The market was already starting to turn up before New Zealand went into lockdown."
Whineray admits working from home made it tougher for his team of 170.
"You have sort of got double stress; market stress and home stress. We just spent a lot more time talking about how people were going.
"What we weren't doing was spending a lot of time pontificating on where the markets were going. One of the things we have noticed in the past where we have got a model for responding to market shocks, if we override it with judgments, often we end up with poorer outcomes than if we just followed what the market was telling us.
"It is a really good lesson that even institutional investors like us, we are all prone to the psychology of losses looming larger than wins, and you feel losses more than you enjoy wins."
So is the fund on track?
"The fund as designed is on track - there is no question the contribution suspension put a dent in the ability to smooth it out but that's past history, we have just got on with it. We can't go back and change it."
Even 20 years after it began, the fund is still in the building-up phase; the first withdrawals by government are not due until the mid-2030s.
"Those withdrawals are still pretty small for 20 years - they are less than 1 per cent of the fund until you get into the mid-2050s and then they step up," Whineray says.
"At the start of the 2050s the model says $1.2b comes out, but at that time the fund is projected to be $300b.
"The serious contribution back to future taxpayers really kicks in, in the middle of the century, about the 2050s. And then the way the model works is, what it is looking to do is smooth out that rising increase [in the cost of NZ Super].
"If ... you graph the line of cost of NZ Super to GDP before this was set up, it was a rising line and the line still rises, but what it is trying to do is flatten it out a bit. Smooth it out so while we are all contributing to it, taxpayers now fund a bit more so taxpayers in the future have this pot of wealth to draw from later. In that sense it is working as it is intended to be."
At its peak, the fund is designed to contribute about 20 per cent of the cost of New Zealand Superannuation. That's a combination of the withdrawals from the fund plus the tax the fund pays.
By 2120 it is estimated the fund will be worth $2 trillion. That long-term view gives it a huge investment advantage but also means it has to pay close attention to factors like climate change.
But not all are convinced of the fund's worth.
Retirement policy expert Michael Littlewood has been an opponent of the fund since it was set up.
"I've always said it addresses the wrong problem because if the problem is the escalating cost of New Zealand Super, then this doesn't change that because whatever happens in the fund, the cost of the NZ Super is the dollars that are paid out.
"The fund doesn't change that number. Without some sort of review of the benefits, the cost is going to be the cost. It will be the number of people aged over 65 multiplied by the annual benefit."
Littlewood says the fund's role to smooth out the cost the NZ Super is one argument for it.
"But come 2033 - and you have got a bunch of politicians deciding to allocate tax money - do you really think they will reduce the amount of tax they collect from the population by the amount of money coming out of the New Zealand Super Fund?
"Because you have to believe that if you think the NZ Super Fund is going to make a difference to the smoothing of the costs.
"I think what is more likely is they will see the NZ Super Fund withdrawals as being free money and the tax rates will stay the same and tax collection will stay the same and all of a sudden we have got $100b coming out of the fund to spend on other things. So total government expenditure will go up, not down."
He argues that if smoothing is the aim, there needs to be a cast iron commitment that total taxes will come down by the same amount as the withdrawals.
Instead, Littlewood believes the fund would be better wound up and the money used to repay government debt, especially in the current climate where debt levels have climbed thanks to Covid's costs.