Tax Return Corrections From 1 October 2026 Under PER-12/PJ/2026

PER-12/PJ/2026 was issued on 28 September 2026 and took effect on 1 October 2026, amending PER-11/PJ/2025. The main change is how a corrected return is calculated. Article 12(2a) requires an Article 21/26 correction to take into account all tax already paid for the period being corrected.

Previously Coretax compared the corrected return with the return being corrected. According to the tax office’s own briefing material, a correction from one overpayment to a smaller one therefore created an apparent underpayment: the taxpayer had to pay, with potential penalties, while still in an overpaid position.

An example from the tax office

PT KLM’s October 2026 Article 21 return, on its second correction, shows an overpayment of Rp60 million. Further review shows the amount withheld should have been Rp15 million, not Rp10 million. A third correction brings the overpayment to Rp55 million.

Under the old method that difference read as an underpayment, and the withholder had to pay Rp5 million. Under the new method there is no payment, because the comparison is with all tax paid for the period. If the Rp60 million had already been carried to November, the compensation balance becomes negative Rp5 million and is taken into the next normal return.

The same approach applies to unified withholding returns, VAT returns, and annual returns for individuals and companies, with their own deductions such as refunds already received.

Effects to plan for

Article 129A(1) provides that rights and obligations follow the last correction filed. If an overpaid return with a refund application is corrected, the application is not processed further while no decision has been issued or the audit has not begun. Preliminary refund applications made by separate letter stop too.

Companies paying Article 29 tax by instalment need more care. Under Article 129B, correcting the annual return cancels the instalment or deferral decision from the day the correction is filed.

The existing condition stays: an Article 21/26 return can be corrected only while the Director General of Taxes has not begun an audit of that period.

What the tax team should do

First, list returns from January 2025 onward that are due for correction, separating those filed before 1 October and still in process. Before filing a correction, check three things: any refund in progress, any instalment decision, and the compensation balance.

If employees will sign withholding slips, set the appointment in the Taxpayer Portal and record who holds that authority.