Tax revenue
Tax revenue is a non-exchange transaction and is accounted for in accordance with PBE IPSAS 23 Revenue from Non-Exchange Transactions.
This means the payment of tax in itself does not entitle a customer to an equivalent value of services or benefits because there is no direct relationship between paying tax and receiving Crown services and benefits.
Tax revenue is recognised when a taxable event has occurred, the tax revenue can be reliably measured and it is probable that economic benefits will flow to the Crown.
Tax revenue is recognised at face value as the fair value is not materially different from the face value.
The New Zealand tax system is based on self-assessment where customers are expected to understand the tax laws and comply with them. IR helps customers comply and addresses non-compliant activities. Most people pay their fair share of tax. For the minority who do not, IR intervenes and encourages them to do the right thing. However, such procedures cannot be expected to identify all sources of unreported income or other cases of non-compliance with tax laws. IR is unable to reliably estimate the amount of unreported tax.
Income tax
Income tax is recognised on an accrual basis in the period the taxable event occurs. It is deemed to accrue evenly over the period to which it relates.
Estimation of income tax revenue
Where income tax returns have not been filed for the relevant period, accrued income tax revenue receivable or refundable has been estimated based on tax payments and/or provisional assessments for that period, or the prior year residual income tax or provisional assessments and payments information.
An estimation of the impact on tax revenue of significant new tax policies or tax rate changes is recognised from the date the policy or rate change takes effect, based on forecast tax policy costings.
Tax revenue is recognised proportionally based on the balance date of the customer. The amount of income tax receivable or refundable is not known with certainty until income tax returns for the period have been filed. The filing of income tax returns can happen more than a year after the end of the tax year. For example, 2025 income tax returns may not be filed until March 2026 (or after) and 2026 income tax returns may not be filed until March 2027 (or after).
Growth assumptions
While the majority of customers make provisional tax payments during a year using a 5% uplift under legislation, the income tax revenue estimation process is based on a rebuttable presumption that the forecast of firms’ net operating surplus, from the most recent Treasury forecast, is the best estimate of the expected uplift for unfiled returns unless rebutted for material impacts. The firms’ net operating surplus is a component of Income Gross Domestic Product (GDP) and is designed to measure net profits of businesses. This measure is approximately equal to accounting profit before taxes, dividends and interest, but after depreciation.
The following assumptions have been used in these financial statements:
- An annual average growth in firms’ net operating surplus for the tax year to 31 March 2025 of 0.65%.
- An annual average growth in firms’ net operating surplus for the tax year to 31 March 2026 of 10.42%.
The March 2025 tax year growth assumption is the annual growth rate derived from the Stats NZ quarterly national accounts data (income, saving, assets and liabilities) released in July 2025.
The March 2026 tax year growth assumption is from the Treasury’s most recent forecast of firms’ net operating surplus growth in the Budget Economic and Fiscal Update 2025, which was finalised on 7 April 2025 and published on 22 May 2025. There is no more up-to-date publicly available information in respect of firms’ net operating surplus for the 2026 tax year and, therefore, we have not rebutted the presumption to use the Treasury’s forecast of firms’ net operating surplus growth. For the 2026 income tax year, which ends on 31 March 2026, the period from 1 April 2025 to 30 June 2025 is included in these financial schedules.
The non-March balance dates use a pro-rata calculation of these rates.
Estimation judgements and assumptions
The measurement of income tax accruals requires significant estimates, judgements and assumptions and has a number of uncertainties. These include the following:
- Where customers have chosen to estimate their provisional tax, income tax revenue is recognised based on the most recent estimate provided to IR.
- Where customers subject to the provisional tax regime (calculated using the standard option) have not yet filed an income tax return:
- for customers with March balance dates for the 2025 income tax year, revenue is estimated as 100.65% of the prior year residual income tax
- for customers with March balance dates for the 2026 income tax year, revenue is estimated as 110.42% of the prior year residual income tax
- for all other income tax years, provisional tax assessments are recognised as revenue based on the provisional tax method adopted by the customer. Provisional assessments are based on 105% of the prior year residual income tax.
- Where customers have made payments for more than the provisional tax assessment (for both the standard and estimation option), their credit balance is also accrued as revenue.
- Where customers have made payments to IR but have not submitted a provisional tax assessment for the period, an estimate is made based on the payments.
- For customers who had a receivable or refundable residual income tax in the prior year but are not subject to provisional tax, the estimation is based on the prior year residual income tax adjusted for the relevant tax year growth assumption.
- For customers who are subject to provisional tax and have not filed their income tax return for the previous period, an estimate is made of the tax revenue receivable and refundable at year end based on prior year provisional tax assessments and any prior year payments that were in excess of their provisional assessment.
- The tax revenue impact of significant new Government policies or tax rate changes is recognised from the effective date of the new policy or rate change based on forecast tax policy costings. The estimation is unwound over the period during which income tax returns impacted by the change are expected to be received. The estimation can be required for up to 2 years from the effective date of the new policy, until the first income tax returns impacted by the change are filed.
Significant new Government policies or tax rate changes
There are 5 significant new tax policy changes that materially impact revenue for 2024–25 and which have been included in the revenue estimation. These tax policies are:
- Investment Boost
- Denial of deductions for commercial and industrial building depreciation
- Restoring interest deductibility for residential property
- Increasing the trustee tax rate to 39%
- Personal income tax and Independent Earner Tax Credit threshold changes.
Revenue recognition for these tax policies is based on forecasted tax policy costings, which is considered to be the best estimate of expected impact available. Recognising this revenue has resulted in an estimated net increase of $278 million in income tax revenue.
Forecast costings contain certain assumptions and are sensitive to customer behaviour, and changing macroeconomic conditions. This means the estimations may be higher or lower than actual revenue, and these differences may be material.
Of the significant policies listed above, the denial of deductions for commercial and industrial building depreciation, restoring interest deductibility for residential rental property and increasing the trustee tax rate policies were effective from 1 April 2024. These changes were not incorporated into the income tax revenue estimation as at 30 June 2024. Had they been included, the estimated impact would have been an increase in revenue of $170 million.
The Investment Boost policy costing, which is used to estimate the revenue impact of this new policy, is based on some assumptions and judgements which have a higher degree of uncertainty. The modelled impacts use aggregate macroeconomic data as an input together with assumptions on coverage within the tax base, and forecasts of growth in investment. Variations in any of these factors can materially affect the actual revenue impact of this policy. Any variations will be recognised in future years as the related income tax returns are filed.
Changes in the estimation of income tax revenue
The estimation model has been refined during 2024–25 to explicitly incorporate the estimated impact of significant tax policy and tax rate changes where income tax returns reflecting those changes have not yet been filed. Under this revised approach, an estimation adjustment is recognised to estimate the impacts of the material tax policy or tax rate changes from the effective date of the new policy/change. Estimations are based on forecast policy costings provided the forecasts are assessed as sufficiently reliable and are unwound over the period during which income tax returns impacted by the change are expected to be received.
Significant assumptions and sensitivities
The significant assumptions and sensitivities behind the estimation of income tax revenue for companies and other persons are:
| Actual 2024 |
Actual 2025 |
|||
|---|---|---|---|---|
| Stats NZ average annual growth in net operating surplus–2024 income tax year | (1.65%) | n/a | ||
| Treasury’s forecast firms’ net operating surplus–2025 income tax year | 4.73% | n/a | ||
| Stats NZ average annual growth in net operating surplus—2025 income tax year | n/a | 0.65% | ||
| Treasury’s forecast firms’ net operating surplus—2026 income tax year | n/a | 10.42% | ||
| Sensitivities ($000) | ||||
| Impact on revenue of a 1% increase in firms’ net operating surplus | $232,000 | $221,000 | ||
| Impact on revenue of a 5% increase in firms’ net operating surplus | $1,168,000 | $1,113,000 | ||
| Impact on revenue of a 10% increase in firms’ net operating surplus | $2,351,000 | $2,240,000 | ||
| Impact on revenue of a 1% decrease in firms’ net operating surplus | $(231,000) | $(221,000) | ||
| Impact on revenue of a 5% decrease in firms’ net operating surplus | $(1,152,000) | $(1,098,000) | ||
| Impact on revenue of a 10% decrease in firms’ net operating surplus | $(2,289,000) | $(2,182,000) | ||
Income tax revenue has a high degree of estimation and is therefore uncertain. Application of key assumptions used in estimating income tax revenue may not necessarily reflect actual tax returns when they are filed. Any variance between the estimate and actual tax return is recognised as revenue when the tax return is filed. The estimation of income tax revenue is challenging because estimation is required so far ahead of the point when a customer is required to file relevant income tax returns. In addition, forecasts of firms’ net operating surplus and the impact of new Government policies are inherently uncertain and volatile.
Goods and services tax (GST)
GST returns are assessed on a 1, 2, 3 or 6-monthly basis and are due the month after the end of the period. At year end, IR estimates the amount of GST outstanding as follows:
- For customers who file a return of GST for the June period, the actual amounts filed are used.
- For customers who have not filed a return, the estimate is based on customer payments for that return period or the most recently assessed GST return.
Source deductions (PAYE)
Employers are required to file an employment information form for each payday. Revenue is assessed based on these forms. June employment information forms filed by employers in July are accrued at year end.
Non-tax revenue
Child support
Child support revenue comprises amounts owed to the Crown and the penalties levied on child support debts owed to both custodial parents and the Crown by parents who pay child support. This revenue is recognised initially at fair value and subsequently tested for impairment at year end.
Interest unwind—Small Business Cashflow Scheme
Small Business Cashflow Scheme loans are initially discounted to fair value. This predominantly reflects the time value of money. As time moves on, loans become closer to being repaid and are therefore worth more. This increase in value is recognised as interest unwind.
The interest unwind has been calculated using a discount rate appropriate for low-rated commercial and unsecured retail lending.
Interest unwind—student loans
Student loans are initially discounted to fair value. This predominantly reflects the time value of money. As time moves on, student loans become closer to being repaid and are therefore worth more. This increase in value is recognised as interest unwind. The interest unwind has been calculated using the official cash rate plus a risk adjustment calculated by the consulting actuaries plus an expense allowance for IR to collect the loans.