More than 4000 people may have paid the wrong amount of tax after an Inland Revenue system glitch miscalculated dividend imputation credits for jointly owned shares.
Written by Swikblog News Desk
Published: 5 December 2025
Thousands of New Zealanders are being urged to re-check their latest income tax assessments after Inland Revenue (IRD) admitted a system error meant incorrect figures were automatically loaded into some returns. The glitch, affecting just over 4500 customers, has sparked fresh questions about how heavily people can rely on pre-filled data in myIR and whether more manual checking is needed in an increasingly automated tax system.
For many affected taxpayers the mistake appears to be in their favour, with IRD estimating an average difference of around $300 per person. But tax specialists say the real issue is trust: if people assume the numbers on screen are right, they may never spot mistakes that leave them paying too much – or too little – tax.
How a myIR pre-fill glitch caused thousands of wrong bills
The error centres on imputation credits attached to dividends from jointly owned shareholdings. One investor who contacted media said he and his wife noticed that while their income and tax information looked correct at the summary stage, the imputation credits automatically carried into their IR3 returns were only half what they should have been.
IRD has since confirmed there was a problem with the way myIR was pre-populating those credits for people who receive dividends with imputation credits from jointly owned shares. Returns started from 26 November onwards are said to be unaffected, but earlier online returns may contain mis-stated credits if taxpayers accepted the pre-filled numbers without manually correcting them.
Roughly 4500 customers are believed to have filed affected returns. IRD says it is working through the best way to amend those returns and will contact people once a fix is in place, aiming to correct the issue without creating extra admin for taxpayers.
Who is most likely to be affected?
The glitch does not affect every salary earner. It is primarily an issue for people who:
- Hold joint share portfolios with a spouse, partner or family member, and
- Receive dividends that include New Zealand imputation credits, and
- File an IR3 return where the information is pre-populated in myIR.
Tax experts note that some people may have paid more tax than necessary, while others could have received a larger refund than they were actually entitled to. Either way, the episode highlights how easy it is for mistakes in back-end systems to flow straight into households’ budgets without being noticed.
Deloitte tax specialist Robyn Walker has warned that any error in pre-populated data is “concerning”, because there is a natural tendency for people to trust what the system serves up if it looks “about right” rather than double-checking against dividend statements.
Will you get money back – or end up owing more?
For now, IRD’s message is that the average amount involved is about $300 and “all in the taxpayer’s favour”, meaning many people are likely due extra credits rather than fresh debts. However, until each affected return is re-run, some customers could still face adjustments that reduce a refund or increase the amount to pay.
IRD says it is looking at options to correct the returns centrally and will be in touch with affected taxpayers once that work is complete. In the meantime, anyone who has recently filed a return involving dividend income from jointly owned shares can still log back into myIR and compare the imputation credits on their IR3 with the numbers shown on their dividend statements.
For those worried about surprise bills generally, IRD’s own guidance on how to avoid an unexpected tax bill is a useful starting point, particularly for people with multiple income sources or complex family situations.
What you should do now
If you think you might be caught up in the error, financial advisers suggest taking these steps:
- Log in to myIR and open your latest return or income tax assessment.
- Check dividend income and imputation credits against your broker or company dividend statements, especially for jointly owned holdings.
- Correct any obvious discrepancies and re-file if necessary, or speak to your tax agent or accountant.
- Watch for correspondence from IRD over the coming days as it works through automatic corrections.
The story also underscores a broader trend: IRD is increasingly focused on closing gaps and tidying up the system, from dividend credits through to crypto gains and overdue tax debt. Recent reporting has highlighted both tougher compliance and the department’s strong return on every dollar spent chasing unpaid tax, a reminder that errors will rarely be left alone for long.
For households already juggling higher living costs, the episode is another reason to treat tax season as something more than a box-ticking exercise. Double-checking the numbers may feel old-fashioned in an age of automation, but as thousands of New Zealanders are now discovering, it can be the difference between losing hundreds of dollars and catching a mistake before it hits your bank balance.
And just as fans dissect every decision in a high-stakes football clash like the North London Derby, taxpayers may now start scrutinising their online assessments with a little more intensity too.
