The Māori economy represents $50b in assets, about six per cent of New Zealand's total asset base.
The report, with guiding metrics, was distributed to participants earlier this year.
It showed the overall trend for post-settlement iwi had similarities to the start-up "hockey stick" effect with initially modest capital growth starting to build.
For participants, the most common asset in the top quartile for underlying returns was the significant holdings in managed funds which have performed well in recent years.
On the flip side, most participants in the lower quartile were actively managing large farms.
"In many cases cultural reasons were an important driver in the investment decision. This highlights non-economic considerations may be impacting financial outcomes," said Harrison.
One of the hardest commercial decisions for iwi was whether to distribute or reinvest profits, said the report, which this year included new metrics to help iwi discuss whether they have the right balance between earnings from business operations and how much they're investing in non-business activities.
Balance sheets showed, on average, just over half of iwi assets comprised cash and managed funds. These were available when promising investment opportunities arose.
Maori investment, historically focused in primary industry, had recently been extending into tourism, horticulture and commercial property.
Headwinds for iwi investment included exposure to commodity cycles and new challenges confronting the primary sector, in which iwi on average have one-third of their assets, said the report.
Fishing and farming faced increasing sustainability scrutiny and along with forestry, were threatened with disruption from science and technology-derived alternatives.
These assets had largely been returned through settlements or had been bought with cultural considerations, and were generally not for sale.
This situation put increased pressure on the rest of the assets to ensure they were allocated or re-allocated to best-fit investments that provided greater returns with the right balance between income and growth, the report said.
Business investment also tended to be swimming against the tide, it said.
Over the past three years, although the median reported dividends represented about one-third of pre-tax commercial operating profits, ANZ estimated that half was actually required to cover the non-commercial operating deficits.
"We can see those tribes 10-plus years since settlement have a median non-commercial operating deficit that is more than 50 per cent larger than others, so you would expect the demands on commercial profits will only increase going forward as tribes become more established - a pressure already felt by many commercial boards.
"Add to this the Māori population growth and inflation and iwi need to generate 3.5 per cent just to stand still."