When does a company need to file IR4 vs IR4S?

IR4 is the standard company income tax return for resident NZ companies. IR4S (the older shortened return) has been retired and replaced by streamlined IR4 schedules for smaller companies. Most companies now file IR4 with a dividend-withholding schedule (IR4J) and shareholder details schedule (IR4S as an annex) — your filing platform handles the schedule split automatically.

What about look-through companies?

A look-through company (LTC) does not file an IR4. It files an IR7 partnership-and-LTC return and the underlying profit or loss flows through to the owners’ individual IR3 returns. The owners pay tax at their personal marginal rates rather than the flat 28% company rate. Switching from a standard company to LTC status requires an LTC election filed with IRD.

How do I get the tax-agent extension?

Link the company to a registered tax agent in myIR before the self-filer due date (7 July following balance date for 31 March companies). The company must not be in arrears on prior-year IR4 or GST. Once linked, the company falls inside the agent’s extension-of-time arrangement and the IR4 due date typically moves to 31 March of the following year, with terminal tax due 7 April.

What if my balance date is not 31 March?

Companies with an approved non-standard balance date (for example 30 June or 31 December) file the IR4 three months and seven days after balance date for self-filers — or under the tax-agent extension arrangement if linked. Approved non-standard balance dates are common for foreign-parented companies aligning to a global financial year and for seasonal industries.

Key dates Published 2026-06-06 · 6 min read

IR4 due date NZ — company income tax return dates

By the TaxAccountants.co.nz editorial team · Published 2026-06-06

When the IR4 company return is due for standard and non-standard balance dates, how the tax-agent extension changes the date, which entities skip IR4 entirely, and why the Companies Office annual return runs on a separate calendar.

In one paragraph

For a standard 31 March balance date, the IR4 is due 7 July after balance date if the company self-files, or 31 March of the following year if it is linked to a registered tax agent. Non-standard balance dates file three months and seven days after balance date for self-filers. Look-through companies file an IR7 instead of an IR4. Source: IRD — key dates.

Standard 31 March balance date

Most NZ companies use a 31 March balance date that aligns with the income-tax year. For the 2026 income year (1 April 2025 – 31 March 2026): self-filer IR4 is due 7 July 2026; tax-agent-linked IR4 is typically due 31 March 2027 under the extension arrangement. Source: IRD — key dates.

Terminal tax — the wash-up between the IR4 figure and provisional tax already paid — is due 7 February 2027 for self-filers, or 7 April 2027 for tax-agent-linked filers.

Non-standard balance dates

Some companies have an IRD-approved non-standard balance date, often to align with an offshore parent or a seasonal business. The self-filer IR4 due date for these is three months and seven days after balance date — so a 30 June balance date files by 7 October following balance, and a 31 December balance date files by 7 April following balance. Tax-agent-linked companies fall inside the agent’s extension arrangement. Source: IRD — income tax for businesses and organisations.

The tax-agent extension

Registered tax agents have an extension-of-time arrangement with IRD that lets them file client returns progressively through to 31 March of the year after balance date. A company qualifies if it is linked to the agent before the self-filer due date and is not in arrears on prior-year IR4 or GST. Linking after the self-filer date does not retroactively cure late filing for that year.

Entities that do not file an IR4

Look-through companies file an IR7 (the partnership-and-LTC return) and the result flows to the owners’ IR3 returns at personal marginal rates. Certain charitable and tax-exempt entities have separate filing obligations. Companies in liquidation file final IR4s up to the cessation date and the liquidator handles the wrap-up. Source: IRD — income tax for businesses and organisations.

Companies Office annual return — separate calendar

The Companies Office annual return is unrelated to IR4. It is filed via the Companies Office portal in the company’s allocated annual-return month, with its own fee and its own penalty regime. Missing it can trigger removal from the register. Many small-business owners conflate the two — they are entirely separate obligations, run by different agencies.

Provisional tax runs on its own dates

Provisional tax instalments for a 31 March balance date fall on 28 August, 15 January and 7 May, regardless of whether the company is self-filed or tax-agent-linked. Missing an instalment exposes the company to UOMI and, in some cases, late-payment penalties. Source: IRD — provisional tax.

Related on TaxAccountants.co.nz

NZ income tax calculator — useful to scope terminal tax before filing.
NZ income tax rates 2026 — the personal scale that LTC owners pay on flowed-through profits.
Sole trader vs company NZ — structure decision before you incorporate.
GST registration threshold — a separate registration calendar for the company.

IR4 deadline closing in?

Linking a company to a registered tax agent before the self-filer date avoids the late-filing penalty and gives you the extension window. We refer every quote request to Lynch & Associates, our Auckland partner firm of CAANZ-member accountants and IRD-registered tax agents, who will reply within one business day.

Get a quote — free for users

Sources

Editorial note: Where 7 July or 31 March falls on a weekend or public holiday, the due date rolls to the next business day. Verified 2026-06-06.

Disclosure: TaxAccountants.co.nz is an introduction service. Quote requests are referred to Lynch & Associates Chartered Accountants.