Form C-S 2026: file by 30 November and check your CIT rebate

A Singapore company files its Year of Assessment (YA) 2026 tax return on IRAS’s myTax Portal by 30 November 2026. The form depends on revenue and on what the company claims: Form C-S if annual revenue is S$5 million or below and it meets IRAS’s other conditions, the simpler Form C-S (Lite) if it qualifies for Form C-S and revenue is S$200,000 or below, and Form C if it qualifies for neither. A company that did no business and had no income files a short dormant-company form, or nothing if IRAS has granted it a filing waiver.

Company tax is a flat 17% of chargeable income, after any partial tax exemption or start-up exemption. For YA 2026, IRAS marks the CIT Rebate as enhanced to 50% of tax payable, with the rebate and a S$2,000 cash grant together capped at S$40,000. IRAS says it applies the rebate when it assesses the return, so the chargeable income you declare should not include it.

This is general information from IRAS pages read on 17 October 2026, not tax advice. A tax agent or IRAS can confirm what applies to your company.

Which form does your company file for YA 2026?

Work down these questions and stop at the first form that fits, using the criteria on IRAS’s filing season page.

1. Did the company carry on no business and have no income in the financial year? Check its status under “Update Corporate Profile” on myTax Portal. “No Business Done” means a waiver has been granted and no return is needed. “Active” means the Form for Dormant Company, which asks for two essential declarations.
2. Is it incorporated in Singapore, with revenue of S$5 million or below and income taxed at 17%, and is it not claiming carry-back of current year capital allowances or losses, group relief, investment allowance, or foreign tax credit and tax deducted at source? If any part fails, file Form C, with financial statements, tax computation and schedules submitted together with it.
3. If question 2 is a clear yes, is revenue S$200,000 or below? Then the company can file Form C-S (Lite), which needs six essential fields. Otherwise file Form C-S.

IRAS’s guidance says to set aside at least 10 minutes for Form C-S or Form C-S (Lite) and at least 30 minutes for Form C once the documents are ready. For the simplified forms, the financial statements, tax computation and schedules are kept and sent only if IRAS asks, apart from an IP writing-down allowance declaration. The form-choice pages we read do not define “revenue”. IRAS’s ECI page defines it, for ECI purposes, as a company’s main source of income, excluding separate-source income such as interest, dividend and rental income that does not arise from its principal activity. We did not confirm that the same definition governs the choice of form, and we did not open the explanatory notes IRAS links. If revenue is close to S$200,000 or S$5 million, read those notes or ask a tax agent.

Does every company have to file by 30 November?

Not quite every company. IRAS says all companies must file by 30 November 2026 unless a waiver has been granted, and its scenario table shows who does not need to. A company incorporated in 2025 files if its first accounts closed in 2025 and it earned income or started business that year; it does not if it closed its first accounts without starting business or receiving income in 2025, or did not close them in 2025. A loss-making company still files, as long as it carried on business or received income. A dormant company’s duty depends on the profile status in question 1.

How is YA 2026 company tax worked out, and where does the 50% rebate fit?

IRAS’s rates page gives these pieces without a numbered sequence; our summary of how they fit together is:

1. Start from chargeable income in your tax computation.
2. Apply the partial tax exemption: 75% of the first S$10,000 and 50% of the next S$190,000, at most S$102,500. Companies in their first three YAs may qualify for a start-up exemption instead.
3. Tax the rest at 17%, then subtract tax set-offs such as foreign tax credit.
4. Take the rebate at 50% of what is left, capped at S$40,000. A company eligible for the cash grant gets no rebate if 50% of its tax is S$2,000 or less, and otherwise the rebate less S$2,000. An ineligible company gets the full rebate.

The grant goes to companies that are active when it is paid and made CPF contributions in calendar year 2025 for at least one Singapore citizen or permanent resident employee, excluding shareholders who are also directors. IRAS said eligible companies would receive it automatically by the second quarter of 2026. IRAS says it is not shown in the estimated tax payable on the filing acknowledgement page and is accounted for only in the final tax payable on the NOA. The page does not say what amount companies were actually paid or how any difference between the earlier S$1,500 minimum and S$2,000 is settled, so compare what you received with the NOA. The grant is separate from the SME Cash Grant 2026, which IRAS describes as up to S$2,500 in November 2026, based on local employees between April and June 2026. It tests CPF contributions in 2025, not the wage floors in our Progressive Wage Model checklist.

Worked example (illustrative). Company X is fictional: a 31 December 2025 year-end, past its first three YAs, income taxed at 17% only, no set-off, and a Singapore citizen employee on CPF in 2025, so it is active, meets the local employee condition and received the S$2,000 grant. Chargeable income before exemption is S$120,000.

• Exemption: S$7,500 (75% of S$10,000) plus S$55,000 (50% of the next S$110,000) is S$62,500.
• Chargeable income at 17%: S$120,000 less S$62,500 is S$57,500, so tax is S$9,775.
• Rebate at 50%: S$4,887.50. That is above S$2,000, so the NOA rebate is S$4,887.50 less S$2,000, or S$2,887.50.
• Net tax on the NOA: S$9,775 less S$2,887.50 is S$6,887.50. With the grant already received, the total benefit is S$4,887.50, which is 50% of the tax.

Without the grant, the full S$4,887.50 rebate would apply and net tax on the NOA would be S$4,887.50. By our arithmetic from IRAS’s formula, eligibility for the grant changes the total benefit only when 50% of the tax is S$2,000 or less.

Checked against IRAS. IRAS shows figures after the exempt amount and does not say which exemption its examples use. Assuming the partial tax exemption applied (our arithmetic, not IRAS’s), Examples 2 to 4 work back to S$155,000, S$40,000 and S$400,000 before exemption, and the method reproduces each published total:

• Example 2 (no grant): S$75,000 after the S$80,000 exemption; tax S$12,750, less S$750 set-off, is S$12,000; rebate S$6,000; net tax S$6,000.
• Example 3 (grant, low profit): S$17,500 after the S$22,500 exemption; tax S$2,975; half is S$1,487.50, under S$2,000, so no rebate; net tax S$2,975.
• Example 4 (grant): S$297,500 after the S$102,500 maximum exemption; tax S$50,575, less S$175, is S$50,400; rebate S$25,200 less S$2,000 is S$23,200; net tax S$27,200.

By our arithmetic the S$40,000 ceiling is reached when tax after set-offs hits S$80,000. IRAS’s Example 5 (gross tax S$124,575, partly at a 10% concessionary rate, no set-off) applies it: a rebate of S$38,000 after the S$2,000 grant. One trap: on 17 October 2026 IRAS’s rates page and ECI page both still show the earlier Budget 2026 terms (40% and a S$30,000 limit; the rates page also a S$1,500 minimum grant) directly above the updated 50% and S$40,000 (the S$2,000 grant appears on the rates page only). Our inference: a source quoting 40% is probably quoting those earlier terms.

What if the company has already filed ECI, or has not?

Estimated chargeable income (ECI) is a separate filing, due within 3 months of year-end: 31 March 2026 for a 31 December 2025 year-end, per the ECI page and due dates page. It is not needed when revenue is S$5 million or below and ECI is nil. If the return’s chargeable income is lower than the ECI, IRAS refunds the excess tax paid earlier automatically; if higher, the additional tax is due within 1 month of the NOA. A company that had to file ECI but did not may get an estimated NOA, payable in full within 1 month even if it objects, with objections due within 2 months. IRAS said it would allow the rebate in an ECI-only assessment by June 2026, and in a Form C-S, C-S (Lite) or Form C assessment that was not yet finalised by August 2026.

What happens after filing, and which dates come next?

IRAS reviews the return and issues the NOA, which you can retrieve on myTax Portal. Diarise these dates:

• Until 30 November 2026: a draft saved in the portal is kept until the due date.
• 30 November 2026: the filing deadline, and the date IRAS gives for emailing “Appeal for CIT Rebate Cash Grant”, with supporting documents, through myTaxMail if an active company meets the local employee condition (for example under a centralised hiring or secondment arrangement) but did not receive the grant by the second quarter of 2026.
• Within 1 month of the NOA date: pay, by GIRO, PayNow QR, AXS or Internet Banking, even if a revision or objection is filed.
• Within 2 months of the NOA date: revise or object through the Revise/ Object to Assessment digital service.

For illustration, since the pages we read do not say when notices will issue, an NOA dated 15 December 2026 would put payment at about 15 January 2027 and the revise-or-object limit at about 15 February 2027. Count from the date on your own notice. IRAS also plans to make that digital service compulsory for objections and revisions from 1 July 2027; the change is to be included in the Finance (Income Taxes) Bill 2026, which will undergo public consultation.

What to check before you file

• Someone at the company or its tax agent holds Corppass “Approver” authorisation for Corporate Tax (Filing and Applications).
• The profile status matches what the company did in financial year 2025, and you have noted the revenue figure that chose the form.
• Financial statements and tax computation are ready; a routine like our month-end close checklist helps.
• Pre-filled brought-forward allowances, losses and donations match your records, and the rebate is not deducted from chargeable income.
• IRAS’s common errors are cleared: non-deductible items such as S-plated cars, missing receipts or cash transactions, and a non-Singapore dollar functional currency not updated in the corporate profile. On Form C-S (Lite), “Adjusted Profit/Loss before Capital Allowances” is profit after tax adjustments, not the adjustments themselves.
• You know whether the S$2,000 grant arrived. If an active company met the local employee condition but did not receive it, IRAS’s appeal email is due by 30 November 2026.

For other dates in the same window, see our SME compliance calendar for October 2026 to March 2027, or the Operations hub.

Common questions