New research supports previous studies suggesting wealth is concentrated at the top.

Most people in New Zealand have negligible net assets and less than $10,000 cash in the bank, according to an independent analysis of government data.

Researchers at the Victoria University of Wellington Institute for Governance and Policy Studies used long-term survey data by Statistics New Zealand to track earnings, assets, and wealth between 2002 and 2010.

Max Rashbrooke, his father Geoff Rashbrooke and Statistics New Zealand analyst Wilma Molano burrowed into the data to extrapolate a nationwide snapshot of individuals' wealth, and their findings suggest limits to social mobility.

In other words, those at the bottom of the socio-economic heap tend to stay poorer for longer.

READ MORE:

* The truth about inequality

* A 'rich' country, but unequal too

* What's the average Kiwi family?

* The richest 10 per cent own $436 billion: research

Those at the top continue to accumulate assets and wealth.

SUPPLIED Max Rashbrooke co-authored a new analysis of assets and wealth in New Zealand.

Max Rashbrooke​ said the long-term survey data allowed conclusions to be drawn, but the quality of the data was limited because the original information relied on people recalling their assets accurately. Any conclusions about long-term trends were extrapolated from the data, he said.

There was still a "fair bit of mobility" and people moved up in terms of wealth as they aged, paid off student debt and other liabilities, but net wealth was concentrated among high-income earners and the richest tier of the adult population.

"There are a lot of people staying where they are at either end of the spectrum. A very large proportion, just over 50 per cent, if they are poor they are likely to be poor 20 years later. Same for the wealthy.

"That's classic half-glass empty. To look at it differently that shows a lot of movement because half the population moves out over their lifetime.

"It also shows you a lot of people are poor for long periods of time."

The analysis also investigated reported assets over time as statisticians interviewed people every two years for almost a decade.

Unsurprisingly, property is by far the biggest asset class - about 45 per cent of the country's wealth. The next largest asset class, business assets, accounted for 18 per cent of overall wealth.

The amount of wealth held in trusts was $73bn.

In terms of liabilities, the bulk of the total was mortgage debt - at 81 per cent of the total owing.

Property is by far the largest asset class in the country.

Analysing reported bank balances suggested most people - around 60 per cent of the adult population - do not have more than $10,000 in cash.

At the top end, bank balances were an average $69,000 in cash.

Rashbrooke said home ownership was slightly more evenly distributed than other assets - but significant ownership of rental and investment properties was the preserve of the wealthiest 10 per cent.

The net worth (the sum of total assets minus total liabilities) of the country was $815 billion in 2010.

"At the social level...it may be of concern if wealth - and ownership of particular types of asset - is highly concentrated at one end of the spectrum. Concentrations of wealth may also lead to some groups having greater influence on politics than others, and to neighbourhoods becoming increasingly stratified by wealth," the analysis said.

To analyse the numbers, the researchers divided the population into tenths called deciles. For example, decile 1 represents the "poorest" 10 per cent of the population, with a total negative net worth of -$7.8bn.

JESSICA SHAPIRO Credit card debt accounts for two per cent of the country's net debt.

At the other end of the spectrum, the richest 10 per cent of individuals own $436bn - more than half of the entire country's net wealth.

A person in the middle of the adult population owns very little except housing, he said, although the spread of home ownership is more even throughout the population. In the fifth and sixth deciles, the average home ownership asset wealth was between $50,000 and $150,000.

Assets, trust assets, and cash were largely in the hands of the top 30 per cent.

People in the middle - most people, in other words - had a net worth calculated as about $95,000.

The average person in the poorest group had a net worth of around -$6000.

Trust assets and collectibles - art, vintage cars, memorabilia - were the preserve of the wealthiest 10 per cent people, he said. So too was cash in the bank.

"Assets are what you rely on planning for the future, they're what you rely on to get through the tough times. There are different kinds.

"It's important to know what the liquid assets are for the average person. You can recognise why so many people are saying they are struggling. People are really operating on pretty bare bones."

From decile five and up, the level of housing wealth increases significantly.

Rashbrooke said business wealth - equity and ownership stakes in companies - was very concentrated at the top.

"It either tells us that small business ownership is really concentrated at the top end. Or most small businesses are actually not doing very well for their owners.

"There's not much evidence of everyone having a stake in the economy."

Mortgage debt was more evenly spread throughout the population than other asset classes and liabilities. Credit card debt - only two per cent of the country's liabilities - was also more evenly spread.

Rashbrooke said it was important to remember the analysis was based on survey data and this information was used to paint a picture of the population as a whole.

"The poorest decile - not all of them are conventionally poor. It could be a high income with a massive mortgage. And a fair number of people with student loans. They do in theory go up to earn more. So not all those in the poorest tenth are classically lifetime poor."

Among the wealthy, in the very top one per cent, these individuals own, on average, trust assets worth $514,000, home values at $473,000, and have about $162,000 in the bank. These individuals are each worth around $4.3 million.

At the other end, the poorest 10 per cent's wealth profile was dominated by debt, with total liabilities over $15bn. This group has almost $1.8bn in housing assets and $6.1bn in mortgage debt.

"[In] the poorer deciles, the very small amounts of liquid assets, such as cash in bank accounts, indicate that many New Zealanders have little to draw on in case of major life shocks.

"There is little evidence to support the view that ownership of the economy is widely distributed," the study said.

Rashbrooke said the findings were not all bleak but the analysis chimed with previous research on inequality and concerns about inequity becoming entrenched.

"This data [stops in 2010] and in the last seven years we've had the continued explosion of the housing market.

"It does confirm just how unequally wealth is distributed. It shows the average person owns very little, has very little cash in the bank or liquid assets they could draw on in hard times.

"Over 20 years you have very large numbers of people starting poor and they remain poor. If they start wealthy they remain wealthy."