Form C-S, Form C-S (Lite) and Form C are the corporate income tax returns used to report your company's income to IRAS. You file the return that fits your company's revenue and tax position. The annual deadline is 30 November of the relevant Year of Assessment (YA).
A shorter form means fewer fields to complete. It doesn't remove the need to prepare the accounts and tax computation behind the return.
Which tax return should your company file?
Swipe sideways to see the full table.
| Return | Who can use it? | Documents submitted with the return |
|---|---|---|
| Form C-S (Lite) | A company that meets all Form C-S conditions and has annual revenue of S$200,000 or less. | No financial statements or tax computation attached, unless IRAS requests them. |
| Form C-S | A Singapore-incorporated company with annual revenue of S$5 million or less that meets the conditions below. | No financial statements or tax computation attached, unless IRAS requests them. |
| Form C | Required when the company does not qualify for the simplified returns. It is not only for large companies. | Financial statements, tax computation and supporting documents, subject to the full-XBRL exception below. |
Form C-S (Lite) is a shorter version of Form C-S. Eligible companies can still choose Form C-S or Form C instead. Dormant companies have a separate filing option, explained below.
What are the conditions for Form C-S?
Revenue alone isn't enough. Under IRAS' eligibility rules, your company must meet all four conditions:
- It is incorporated in Singapore.
- Its annual revenue is S$5 million or less. Revenue here means the company's main income source, excluding separate-source income such as interest.
- Its income is taxable at the normal corporate income tax rate of 17%, subject to the exceptions below.
- It is not claiming carry-back of current-year capital allowances or losses, group relief, investment allowance, foreign tax credit, or tax deducted at source for that YA.
Income taxed at a concessionary rate or exempt under a tax incentive can prevent the company from using Form C-S. IRAS allows exceptions for one-tier tax-exempt Singapore dividends and specified foreign-sourced income exempt under section 13(8) of the Income Tax Act.
Example: A company with S$150,000 in revenue that meets the other conditions can choose Form C-S (Lite). A company with S$1 million in revenue that is claiming a foreign tax credit must use Form C, despite being below the S$5 million threshold.
When do you need to file?
The deadline is 30 November each YA. For example, a company with a normal 12-month financial year ending on 31 December 2025 files its YA 2026 return by 30 November 2026. YA refers to the year in which the income is assessed, not necessarily the year the income was earned. Our Year of Assessment guide explains the distinction.
For a newly incorporated company, check when the first return is due based on its first financial year and business activity. If the first accounts cover more than 12 months, the income or loss may need to be attributed to two YAs. Don't assume the whole period belongs to one YA simply because you prepared one set of accounts.
These are separate filings. ECI reports estimated taxable income and is due within three months after FYE unless an exemption applies. Form C-S, Form C-S (Lite) or Form C reports the company's actual tax position. The annual return filed with ACRA is a different corporate filing. Completing one does not automatically complete the others. See our ECI guide for the earlier filing.
What if your company made a loss or was dormant?
A loss-making company still needs to file. Having no tax to pay does not, by itself, remove the filing requirement.
For IRAS purposes, a dormant company is one that did not carry on business and had no income throughout the relevant basis period. It can use the simplified Form for Dormant Company. If IRAS has granted a filing waiver and the company continues to meet its conditions, the annual return to IRAS is not required.
No sales does not necessarily mean dormant. For example, bank interest is still income. Check the company's actual activity and waiver status rather than submitting a dormant return automatically. See IRAS' dormant-company guidance for the conditions.
What documents should you prepare?
Start with completed accounts and a tax computation. The tax computation adjusts the accounting profit or loss for tax purposes, so you should not simply copy the profit figure from your accounts into the taxable-income field.
For Form C-S and Form C-S (Lite), prepare the financial statements and tax computation and keep them available for IRAS. Not attaching them is different from not preparing them.
For Form C, prepare the financial statements, detailed profit and loss statement, tax computation and supporting schedules. Include any claim forms required for the reliefs or allowances you are claiming. Supporting attachments must be in PDF format.
If your company has already filed a full set of financial statements with ACRA in XBRL format, it does not need to submit those financial statements again to IRAS. This does not remove the obligation to prepare them or submit the other required Form C documents. IRAS explains this exception in its basic corporate tax guide.
How do you submit the return?
- Finalise the accounts and tax computation, then confirm which return the company can use.
- Check that the person submitting is authorised in Corppass as an Approver for Corporate Tax (Filing and Applications), or authorise your tax agent.
- Log in to myTax Portal, select the correct company and YA, and complete the relevant return.
- Review the figures and attachments before submission, then save the acknowledgement and filed documents.
For the current portal instructions, use IRAS' filing guide. A company that is closing may also need to file for an advance YA before the normal return becomes available. Our company strike-off guide covers that process.
What happens if you miss the deadline?
IRAS can issue an estimated tax assessment and take enforcement action for late or missing returns. Filing late is still necessary even if the company has no taxable profit.
If you receive an estimated Notice of Assessment, the tax must be paid within one month from the notice date, even if you dispute it. An objection must be filed within two months from that date, together with the outstanding return and required documents. Objecting does not suspend payment. See IRAS' late-filing guidance.
Need help with your company's tax return?
We can help prepare the financial statements, work through the tax computation and file the appropriate return. You can read about our corporate tax filing service or get in touch with your company's financial year end and latest accounts so we can see what's needed.
