Yesterday's announcement is not the end of this saga, with further consultation flagged - particularly around the details of the policy - but legislation is expected to be introduced to Parliament in December and active by July 2018.
The moves are necessarily broad - policy documents and submissions released this morning run to more than 1000 pages - as any crackdown of this nature necessarily requires a comprehensive scope.
If you considered the tax system as a balloon, squeezing only one end merely see the other expand. As the cabinet paper accompanying today's announcement puts it: "Stripping the tax benefits from one type of arrangement is ineffective if multinationals can get the same benefit from switching to a different type of arrangement."
The government has adopted a three-pronged strategy limiting the abuse of debt-loading, the structuring of corporate affairs to avoid the appearance of economic activity in New Zealand (formally referred to as "permanent establishment"), and the abuse of equity-debt hybrid vehicles.
The latter measure has been in-train for years, while the former two are fresher tools sharpened over the past 12 months.
New measures to combat debt-loading include preventing related-party debts where interest rates are jacked-up in order to transfer profits out of New Zealand. New policies will require interest rates to be in line with those paid by parent companies for finance.
Additional measures will also lower the amount of debt companies can be saddled with in order to writeoff the interest for tax purposes. An OECD-recommended cap on interest expenses relative to earnings before interest, tax, depreciation and amortisation was mulled, but discarded.
Hardening permanent establishment rules is a recent addition to the government policy slate and the most likely to draw the interest from activists and corporate taxpayers.
Without permanent establishment, Inland Revenue has no claim to the income of companies. New measures will see interest triggered by Inland Revenue, including if companies employ highly-paid local staff, or have connections to low-tax jurisdictions.
While not named in government documents, these jurisdictions would likely include low-tax havens Singapore, Ireland, the Netherlands and others commonly used by many pharmaceutical and technology companies who have presently structured their affairs to avoid permanent establishment in New Zealand.
But yesterday's announcement isn't all about high-profile corporates: An intriguing coda in documents is a memorial notice for the formerly low-profile New Zealand foreign trusts.
The sector had a torrid time through the Panama Papers affair, particularly over revelations quirks of the structures - notably secrecy and the ability to leverage them into tax-free vehicles - had been abused by the internationally mobile.
Last year's Shewan Report stripped away secrecy, requiring Inland Revenue to be informed of their ultimate beneficiaries. The need for disclosure saw the sector shrink rapidly ahead of the first round of reporting on June 30.
Yesterday's cabinet documents states in addition they will also lose their tax-free status, likely seeing in the industry atrophying further.
Most countries only tax a trust if its trustees are resident, while New Zealand only takes the residency of a settlor into account. In 2014 Treasury noted the "difference between the two approaches creates an arbitrage opportunity" whereby the income of some New Zealand trusts wouldn't be subject to any tax.
The loophole - the arbitraged no-tax New Zealand trust - will now trigger New Zealand tax liabilities.
"When the income of the trust is not tax anywhere in the world because of the different tax treatment the relevant countries place on the trust structure, we recommend the New Zealand trustee be subject to tax ... We anticipate this meaning that most foreign trusts will be taxed in New Zealand on their foreign income."
While the implementation of the above is being delayed to "give these structures time to assess their options," the foreign trust industry may well be mulling, beside taxes, the other certainty in life.
