Singapore: Your responsibility

An adviser can prepare the technical case, the figures and the R&D claim form. None of that moves the claim out of the company's name: the company makes the R&D claim in its own corporate income tax return for the year of assessment.1Source 1IRAS, Research & Development (R&D) Tax Measures (13 August 2026); Income Tax Act 1947 section 14C. If IRAS later finds that the deduction was overstated, your company pays the tax undercharged. The questions on who signs the claim and can we see the full claim before filing? are about making that responsibility real. The people who did the work read the technical descriptions before the return goes in, and the company keeps a copy of what was filed.

• Making the claim. The claim is made in the return for the relevant year of assessment, with the R&D claim form; the IRAS page read states no separate R&D claim deadline.1Source 1IRAS, Research & Development (R&D) Tax Measures (13 August 2026); Income Tax Act 1947 section 14C.
• Revising an assessment. A company that disagrees with its notice of assessment must object within two months of the date of the notice, through the Revise/ Object to Assessment digital service. Relief for an error or mistake in a return, which can include a deduction not claimed, can be applied for in writing within four years after the end of the year of assessment in which the assessment was made. No relief is given where the return followed the practice of the Comptroller generally prevailing at the time.2Source 2IRAS, After filing Form C-S/ Form C-S (Lite)/ Form C (29 May 2026); Income Tax Act 1947 section 93A. Test any offer to claim for earlier years against these dates (cold calls about unclaimed refunds).
• IRAS's time limit. Where a company has been assessed at less than it ought to have been charged, the Comptroller may make an additional assessment within four years after the expiry of the year of assessment (for years of assessment from 2008). There is no time limit where there has been fraud or wilful default.3Source 3Income Tax Act 1947 section 74. A claim can therefore be looked at well after the return has been filed, which is why review support in the engagement letter matters (is review support included?).

If IRAS reduces the deduction, your company pays the tax undercharged, and the tax on an amended or additional assessment is due one month from the date of the Notice of Assessment, even if you object. Singapore differs from the other countries on this site in one respect: the IRAS guidance describes late payment penalties, not interest. A late payment penalty of 5% applies to tax not paid by the due date, and a further 1% for each complete month it remains unpaid, up to 12%, if it is still unpaid 60 days after that.4Source 4IRAS, Late payment or non-payment of Corporate Income Tax (10 August 2026). For an error in the return, a penalty of up to 200% of the tax undercharged can be imposed where there was no intention to evade tax, and up to 400% where there was.5Source 5IRAS, Penalties for errors in tax returns (2 March 2023); Income Tax Act 1947 section 95. Whether the adviser's fee comes down too depends on the engagement letter, not on IRAS: see what happens to the fee if the claim is reduced?

The same penalty provision applies to any person who gives incorrect information affecting the liability of another person to tax.6Source 6Income Tax Act 1947 section 95(1)(b) and (2). That penalty is the other person's; it does not pay the company's tax or penalty, and the engagement letter's liability and indemnity clause is where any contribution from the adviser would be found.

A company that finds an error in a filed return can revise it through the Revise/ Object to Assessment digital service.2Source 2IRAS, After filing Form C-S/ Form C-S (Lite)/ Form C (29 May 2026); Income Tax Act 1947 section 93A. IRAS's Voluntary Disclosure Programme sets out the terms: no penalty for a qualifying disclosure made within the one year grace period after the statutory filing deadline. After that, for corporate tax, the penalty is 5% of the tax undercharged for each year that the error was late in being rectified. The disclosure must be timely, accurate, complete and self-initiated, and made before IRAS sends a query or audit notice.7Source 7IRAS, IRAS' Voluntary Disclosure Programme, e-Tax Guide (Thirteenth Edition) (30 January 2026), paragraphs 2.2, 4.1, 4.2 and 10. Take advice before you use it: the correcting a claim page sets out what to settle first, including what the engagement letter says about the fee on the corrected amount.

If IRAS reviews the claim within the time limit above, it can ask for the evidence behind it. Keep the return and the R&D claim form as filed, the technical case, the cost workings, the project records they rest on, and the engagement letter. Ask for anything the adviser holds that you do not (ownership of records and work).

• If your claim is reviewed and complaints about an adviser in Singapore
• Claim reduced on review and if you are charged a penalty
• The true cost of a claim

Sources

1. IRAS, Research & Development (R&D) Tax Measures (13 August 2026); Income Tax Act 1947 section 14C.   Back
2. IRAS, After filing Form C-S/ Form C-S (Lite)/ Form C (29 May 2026); Income Tax Act 1947 section 93A.   Back
3. Income Tax Act 1947 section 74.  Back
4. IRAS, Late payment or non-payment of Corporate Income Tax (10 August 2026).  Back
5. IRAS, Penalties for errors in tax returns (2 March 2023); Income Tax Act 1947 section 95.  Back
6. Income Tax Act 1947 section 95(1)(b) and (2).  Back
7. IRAS, IRAS' Voluntary Disclosure Programme, e-Tax Guide (Thirteenth Edition) (30 January 2026), paragraphs 2.2, 4.1, 4.2 and 10.  Back