But the thing that interests Business Insider is that more members of this select group are declaring income of less than $70,000 a year - the threshold for the top tax rate of 33 cents in the dollar.
Of the 212 super-rich people who fall under the HWI unit's gaze, 79 declared income of less than $70,000 in the 2013 year.
For the 2014 financial year, 84 declared income below that threshold.
"It is important to note that it is common for income to be declared in other entities, such as trusts and companies," Inland Revenue investigations and advice manager Lynley Sutherland told Business Insider.
The 212 people control 6986 entities, which could include the likes of companies, trusts, or limited partnerships.
Sutherland says the department does not hold information on the number of tax-planning devices the super-rich use, but pointed to the things the IRD keeps an eye on.
Business Insider would wager that at least one of the 212 is under investigation by Inland Revenue, which refuses to provide any firm numbers.
"As you will appreciate, there are a small number of people involved, so releasing the information may make it possible to form inferences about particular individuals," Sutherland says.
And though the number of the super-rich has gone up, the amount of extra tax they were found liable for is down on last year.
In the year to June, the IRD assessed a further $45 million of tax to high-wealth individuals. That has slipped from $77 million during the prior 12 months.
The amount of tax in dispute between IRD and the group also fell from $112 million to $102.5 million.
The last failed finance company trial is now due to begin, more than 10 years after the first collapses began rocking the sector.
At least 50 finance companies fell over during the past decade, leaving investors billions of dollars out of pocket.
And the washup is still hitting New Zealand's corporate shores, with receivers and liquidators picking over the sector's remains.
Regulators, too, have not yet been able wash their hands of the failures and are still to prosecute one last case, involving five men allegedly involved in Mutual Finance and Viaduct Capital.
The three-month trial - in which Paul Bublitz, Bruce McKay, Richard Blackwood, Lance Morrison and Peter Chevin are defending charges brought by the Financial Markets Authority - was due to begin in February.
But Chief High Court Judge Geoffrey Venning this week agreed to delay the case until next August to allow Bublitz, a property developer, more time to get money to pay for a lawyer.
Paul Bublitz, a property developer.
The new start time puts the trial after the 10-year anniversary of some of the early collapses, including Provincial Finance, National Finance and Western Bay Finance - which had all hit the rocks by August 2006.
Given the length of economic cycles, by the time authorities are finally finished with the finance company fallout, could they have some new crisis to contend with?
Admissible evidence?
The late Nick Wevers could feature in the Viaduct/Mutual trial after Bublitz signalled he may try to get FMA interview transcripts with Wevers admitted as evidence. Wevers, a former Viaduct director and chief executive of Blue Chip, died suddenly at home last year, only days after the FMA laid charges against him. The charges against the 59-year-old were subsequently withdrawn.
Nick Wevers, a former Viaduct director and chief executive of Blue Chip, died suddenly at home last year.
Viaduct called in the receivers in 2010, owing 110 investors some $7.8 million, of which $7.5 million was guaranteed. Mutual Finance collapsed in two months later owing about 340 investors $9.3 million, $9 million of which was covered by the Government's retail deposit guarantee scheme.
