Five Key Changes in the Re-Revised Quarterly Tax Circular

Key Changes Taxpayers Need to Know

The Inland Revenue Department has issued the Re-Revised Circular No. SEC/2026/E/06 dated 12 August 2026 relating to the calculation and payment of quarterly income tax instalments.

The new circular amends the original circular dated 3 August 2026 and the revised circular dated 6 August 2026. According to the IRD, these further changes were introduced following requests made by taxpayers.

This article compares the Revised Circular dated 6 August 2026 with the Re-Revised Circular dated 12 August 2026 and explains the five key changes taxpayers and tax practitioners should understand.

Quarterly Instalment Due Dates

The statutory quarterly instalment deadlines remain unchanged:

• First instalment: 15 August
• Second instalment: 15 November
• Third instalment: 15 February
• Fourth instalment: 15 May of the succeeding year

The quarterly instalment continues to be calculated using the following formula:

Quarterly instalment = (A – C) ÷ B

Where:

• A is the gross income tax payable based on the applicable calculation method.
• B is the number of instalments remaining for the year of assessment, including the current instalment.
• C is the total tax paid or credited before the relevant instalment deadline, including previous instalments and applicable WHT/AIT credits.

Five Key Changes Introduced by the Re-Revised Circular

1. Application Restricted to the Year of Assessment 2026/2027

The revised circular dated 6 August 2026 stated that it applied to the:

Year of Assessment 2026/2027 and subsequent years of assessment.

However, the re-revised circular restricts its application specifically to the:

Year of Assessment 2026/2027

Accordingly, the procedures introduced by the re-revised circular should not automatically be applied to subsequent years of assessment unless the IRD issues further instructions.

This is an important change because the circular now operates as a specific procedure for the Y/A 2026/2027.

2. Final SET Can Be Used for the First Quarterly Instalment

The re-revised circular introduces a new facility for taxpayers whose tax computation for the Y/A 2025/2026 has not been finalized by the first instalment deadline.

Such taxpayers may use the final Statement of Estimated Tax (SET) for 2025/2026 when calculating the first quarterly instalment for the Y/A 2026/2027.

This facility applies under the following alternative methods:

No Previous Taxable Income but Current Income Is Expected

This includes circumstances where the taxpayer had no taxable income in 2025/2026 because of:

• Deductible tax losses;
• A tax exemption; or
• Other applicable adjustments,

but expects to have assessable income during 2026/2027.

Previous Income Existed but a Significant Reduction Is Expected

This applies where the taxpayer had assessable income in 2025/2026 but reasonably expects lower income during 2026/2027 due to circumstances such as:

• A significant decline in business;
• An increase in expenditure;
• A reduction in investment activities; or
• The discontinuation of a business or investment source.

The revised circular dated 6 August 2026 did not expressly permit the use of the previous year’s final SET for this purpose.

3. SET-Based Calculation Must Be Revised for the Second Instalment

Where a taxpayer uses the final SET for 2025/2026 to calculate the first quarterly instalment, the calculation must be revised for the second quarterly instalment using the Return of Income for 2025/2026.

The taxpayer is required to submit:

• Attachment 1 for the first quarterly instalment; and
• Attachment 1 (Revised) for the second and subsequent quarterly instalments.

Only one revision is permitted under this arrangement.

Therefore, once the Return of Income for 2025/2026 is finalized, the taxpayer should carefully revise the calculation because the revised basis will apply to the second and subsequent instalments.

4. Attachment Deadline and Submission Procedure Changed

Under the revised circular dated 6 August 2026, the required attachments had to be submitted on or before 15 August of the year in which the first instalment became due.

The re-revised circular extends this deadline to:

30 November 2026

This extension provides taxpayers with additional time to finalize their tax computations and prepare the required attachments and supporting calculations.

However, the extension applies only to the submission of attachments. It does not change the statutory deadlines for paying quarterly income tax instalments.

RAMIS Submission

Attachments relating to the Y/A 2026/2027 may now be uploaded when submitting the Return of Income for the Y/A 2025/2026 through RAMIS.

The relevant upload path is:

Upload Supporting Documents → Supporting Documents → Other Relevant Documents

The document should be named in the following format:

TIN_2627_INSAttachment1

For example:

111122222_2627_INSAttachment1

Where applicable, the document title should be changed to:

• INSAttachment1_Revised; or
• INSAttachment2

Both Attachment 1 and Attachment 1 (Revised) may be submitted on the same date, where applicable.

Taxpayers who wish to submit the documents manually may submit them to:

• The Central Document Management Unit;
• The relevant Metro Office; or
• The relevant Regional Office.

5. Attachment 1 Revised to Identify the Calculation Basis

The re-revised circular introduces an amendment to Attachment 1 – Form No. SEC/2026/SA/01.

Taxpayers must now identify the basis used to calculate the estimated assessable income by selecting one of the following:

• Previous Year Return of Income Basis; or
• Previous Year SET Basis.

This amendment enables the IRD to identify whether the first quarterly instalment calculation was based on the finalized Return of Income or the final SET for 2025/2026.

The taxpayer should select the correct basis and attach the relevant calculations and supporting information.

Summary of the Five Key Changes

What Has Not Changed

The following provisions remain unchanged:

• Statutory quarterly instalment deadlines;
• Quarterly instalment calculation formula;
• Standard basis for taxpayers with taxable income for 2025/2026;
• Alternative methods for taxpayers with no previous taxable income or lower expected income;
• Credit schedule submission deadlines;
• Treatment of APIT and AIT credits;
• Treatment of foreign tax credits;
• Use of Attachment 2 by newly registered taxpayers; and
• Deadlines applicable to mid-year revisions.

What Should Taxpayers Do?

Taxpayers should take the following actions:

1. Follow the Re-Revised Circular dated 12 August 2026 for the Y/A 2026/2027.
2. Determine whether the standard basis or an alternative basis applies.
3. Use the final SET for 2025/2026 only where the applicable conditions are satisfied.
4. Revise the SET-based calculation for the second instalment using the Return of Income for 2025/2026.
5. Submit Attachment 1 and Attachment 1 (Revised), where applicable.
6. Indicate whether the calculation is based on the previous year’s Return of Income or final SET.
7. Submit the required attachments on or before 30 November 2026.
8. Follow the prescribed naming format when uploading documents through RAMIS.
9. Retain the calculations and supporting information used to establish any expected reduction in income.

Conclusion

The Re-Revised Circular dated 12 August 2026 provides additional flexibility to taxpayers whose 2025/2026 tax computations were not finalized by the first quarterly instalment deadline.

The principal changes are the restriction of the circular to the Y/A 2026/2027, permission to use the final SET for the first instalment, mandatory revision using the previous year’s Return of Income, extension of the attachment deadline to 30 November 2026, and amendment of Attachment 1 to identify the calculation basis.

Taxpayers should carefully follow these revised procedures when calculating, documenting and submitting their quarterly income tax instalment position for the Y/A 2026/2027.

This article is provided for general informational purposes only. Taxpayers should consider their individual circumstances and obtain professional advice where necessary.

Circular No: SEC/2026/E/06 (Re-Revised) [12 August 2026]