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How to Object to a Company Notice of Assessment in Singapore
Key Takeaways
- A Singapore company has two months from the date on its Notice of Assessment to object, using Revise/ Object to Assessment on myTax Portal.
- The assessed tax remains payable within one month, even while IRAS reviews the objection.
- IRAS issues four types of company Notice of Assessment, and only Type 2 (estimated) and Type 4 (completed) normally call for an objection.
- An estimated assessment does not correct itself: file the missing ECI or tax return as well as the objection.
- A valid objection states precise grounds and attaches evidence; unresolved disputes can go to the Income Tax Board of Review.
A Notice of Assessment that does not match your expectations is unsettling, especially when the tax payable is higher than your accountant’s computation. The good news is that Singapore has a clear, structured process for disagreeing with the Inland Revenue Authority of Singapore (IRAS). The bad news is that the process runs on tight deadlines, and many companies lose their right to object simply by waiting.
This guide explains what a company Notice of Assessment is, which of the four types need an objection, why notices often look wrong, and exactly how to file an objection that IRAS can act on.
What Is a Company Notice of Assessment?
A Notice of Assessment (NOA) is the official tax bill IRAS issues after it assesses a company’s chargeable income for a Year of Assessment. It states the chargeable income, the exemptions and rebates IRAS has applied, and the tax payable. The NOA is the document you act on: you either pay it or object to it, and in many cases you pay it while you object.
The NOA follows from your corporate tax filings: your Estimated Chargeable Income (ECI), filed within three months of your financial year end, and your Form C-S, Form C-S (Lite) or Form C, due by 30 November. Our guide to Singapore Corporate Tax Filing Deadlines 2026 shows how those dates fit together.
The Four Types of Notice of Assessment, and Which Need an Objection
IRAS issues four types of NOA to companies, and only some call for an objection.
| Type | What triggers it | When it typically arrives | Object if you disagree? |
|---|---|---|---|
| Type 1 | You filed a positive ECI | Shortly after ECI filing | No; revise the ECI instead |
| Type 2 | IRAS estimated your income because you did not file ECI within three months of your financial year end, declared a low ECI, or IRAS raised an advance assessment | After the ECI deadline passes | Yes, within two months, and file the missing ECI or return |
| Type 3 | Your company has complex tax affairs and IRAS issued an estimated assessment pending a full review | By 28 February after filing | Generally no; IRAS finalises it after review |
| Type 4 | IRAS completed the assessment based on your Form C-S, Form C-S (Lite) or Form C, with or without adjustments | By 31 May after filing for straightforward cases | Yes, within two months |
The Type 2 estimated assessment causes the most trouble for SMEs. In practice, what we see with most companies is a director who assumes an estimated bill will correct itself once the accounts are ready. It does not. You must file the outstanding ECI or tax return, and lodge an objection if you disagree with the estimate.
Why a Notice of Assessment Looks Wrong
Most disputed NOAs trace back to one of five causes.
IRAS estimated your income. You missed the ECI or Form C-S deadline, so IRAS used its own figure, which is rarely in your favour. We explain the consequences of late filing in Missed the 30th Nov Tax Deadline? Penalties in Singapore.
IRAS disallowed an expense. IRAS treated a cost as private, capital or otherwise non-deductible. Private car expenses and entertainment without a clear business link are frequent examples.
The wrong exemption scheme applied. A new company may expect the start-up tax exemption but receive partial tax exemption, or the reverse. Our guide to the Singapore Corporate Tax Rate 2026 explains both schemes.
Losses or capital allowances did not carry forward. A change of more than 50% in shareholding can forfeit unutilised items unless the company meets the shareholding test or obtains a waiver.
A data error in the return itself. A mistyped revenue figure or adjustment flows straight into the assessment.
Compare the NOA line by line against your tax computation before you decide to object. Some differences are IRAS correcting your own error, and objecting to those wastes time and goodwill.
How to Object to a Company Notice of Assessment
Follow these steps within two months of the NOA date.
1. Read the NOA carefully. Confirm the Year of Assessment, the chargeable income, the exemptions and rebates applied, and the tax payable.
2. Identify the exact disagreement. Pinpoint the specific adjustment or figure and the amount in dispute.
3. Gather evidence. Collect the financial statements, tax computation, invoices, contracts and schedules that support your position. Our guide to What Records Should You Keep for Business Tax Filing in Singapore? lists what you should already hold.
4. File online. Log in to myTax Portal with Corppass and use Revise/ Object to Assessment. IRAS strongly encourages this digital channel.
5. State precise grounds. Explain why the assessment is wrong and what the correct figure should be. A bare statement of disagreement does not count as a valid objection.
6. Pay the assessed tax on time. Payment within one month avoids late payment penalties, and IRAS refunds any overpayment if the objection succeeds.
7. Respond to IRAS queries promptly. IRAS may ask for more documents during its review, and slow responses delay the outcome.
For a Type 2 estimated assessment, file the overdue ECI or Form C-S at the same time, because IRAS needs your actual figures to revise the estimate.
Objection Deadlines at a Glance
| Event | Company deadline |
|---|---|
| Pay the assessed tax | Within 1 month of the NOA date |
| File a Notice of Objection | Within 2 months of the NOA date |
| Lodge a Notice of Appeal to the Board of Review | Within 30 days of IRAS’s Notice of Refusal to Amend |
| Lodge a Petition of Appeal | Within 30 days after the Notice of Appeal |
| IRAS time limit to raise an additional assessment | 4 years after the end of the Year of Assessment (no limit for fraud) |
What Happens After You Object?
IRAS reviews the objection and either agrees and issues a revised assessment, or disagrees. If both sides cannot resolve the dispute, IRAS issues a Notice of Refusal to Amend. The company can then appeal to the Income Tax Board of Review by lodging a Notice of Appeal within 30 days of the refusal, followed by a Petition of Appeal within 30 days after that.
Most SME objections never reach the Board. A well-documented objection with a clear computation usually resolves at the review stage, often after one or two rounds of questions.
What If You Miss the Two-Month Deadline?
IRAS can accept a late objection only where the company shows a reasonable cause for the delay, such as absence from Singapore or illness. Do not rely on this. If the window has closed and you find an error in your own return, write to IRAS and consider the Voluntary Disclosure Programme, which reduces penalties for errors you report yourself.
Remember that the process works both ways. IRAS may raise an additional assessment within four years after the end of the Year of Assessment if it finds new information, and without time limit where fraud is involved.
What Businesses Get Wrong About Notices of Assessment
Ignoring estimated assessments. A Type 2 notice becomes final if you neither file nor object. The tax is then legally due, even if it overstates your real income.
Withholding payment while objecting. Objecting does not suspend payment. Late payment penalties apply on top of any eventual revision.
Objecting without numbers. An objection that only says “we disagree” fails. IRAS needs the corrected figure and the evidence behind it.
Confusing GST and income tax processes. GST assessments have their own objection process; see GST Filing Mistakes That Businesses Should Avoid for the GST side.
Waiting for the accountant to notice. NOAs go to the company. If nobody owns the review, the two-month window closes quietly.
How Grof helps you handle IRAS assessments without the hassle
A disputed Notice of Assessment is an evidence question before it is a tax question. Most companies that lose objections do so because the computation or supporting documents were never organised, not because their position was wrong. Grof keeps your tax file ready, so a wrong NOA becomes a short, well-documented conversation with IRAS.
In practice, that looks like:
- Reviewing every NOA when it arrives. We compare each notice against the filed computation and flag differences well within the two-month window.
- Separating real disputes from corrections. We tell you when IRAS is right, so you only object where it counts.
- Preparing precise objections. Grounds, corrected figures and supporting schedules go in together through myTax Portal.
- Fixing estimated assessments fast. We file overdue ECI or Form C-S alongside the objection.
- Staying the point of contact. If IRAS follows up with questions, our tax team responds with you.
If a recent Notice of Assessment looks wrong, ask Grof’s accounting and tax team to review it before the two-month window closes.
