Form C-S vs Form C-S (Lite) vs Form C

Singapore has three corporate income tax returns, and most owners assume the choice is about revenue. Revenue is only one of four conditions. A company well under the threshold can still be pushed onto the full form by a single relief it decides to claim.

All three are filed through myTax Portal by 30 November of the Year of Assessment — the calendar year after your financial year end. The obligation to make a return sits in s62 of the Income Tax Act 1947.

Which form applies

	Form C-S (Lite)	Form C-S	Form C
Annual revenue	S$200,000 or below	S$5 million or below	Any
Must meet the four conditions	Yes	Yes	No
Fields to complete	6	18	Full return
File financial statements?	No	No	Yes
File tax computation?	No	No	Yes
File supporting schedules?	No	No	Yes

The only difference in qualifying between Form C-S and Form C-S (Lite) is the revenue figure. Everything else is identical.

Qualifying for the Lite form does not oblige you to use it — IRAS confirms a company that qualifies may still file Form C-S or Form C. In practice there is rarely a reason to volunteer for more fields.

The four conditions for Form C-S

Your company qualifies only if all four are true:

1. It is incorporated in Singapore.
2. Its annual revenue is S$5 million or below.
3. It derives only income taxable at the prevailing corporate rate of 17%.
4. It is not claiming any of the following in that Year of Assessment:
   • carry-back of current year capital allowances or losses
   • group relief
   • investment allowance
   • foreign tax credit and tax deducted at source

Condition 4 is the one that catches people. A company with S$400,000 of revenue that decides to carry back a loss, or to claim credit for tax withheld by an overseas customer, files Form C regardless of its size. Which form applies is therefore not settled until you know what you are claiming — and that is usually decided late, when the computation is being prepared.

What counts as revenue

Revenue means the company's main income source, excluding separate source income such as interest. It is not total receipts, and it is not profit. A company with S$4.9 million of trading revenue and S$300,000 of interest income is still within the S$5 million threshold.

Concessionary and exempt income

Form C-S should not be filed where the company derives income that is tax exempt or taxed at a concessionary rate, such as under a tax incentive. There are two exceptions — Form C-S remains available where the income is:

• one-tier tax exempt Singapore dividends, or
• specified foreign-sourced income exempted from tax under s13(8) of the Income Tax Act 1947.

This is commonly misread in both directions. Receiving Singapore dividends does not push you onto Form C. Holding an incentive that taxes part of your income at 5% or 10% does.

"Not filed" does not mean "not needed"

Form C-S and Form C-S (Lite) filers do not submit financial statements or a tax computation. They must still prepare both and be ready to produce them on request.

The distinction matters more than it sounds. The saving is administrative, not substantive: you cannot complete even the six fields of Form C-S (Lite) honestly without accounts and a computation behind them, and IRAS can ask to see both. An owner who reads "financial statements not required" as "financial statements not needed" has misread it, and will have nothing to produce when asked.

A company must file even if it received no income or is making losses. There is no revenue floor below which the return stops being required.

Dormant companies

From YA 2020, a dormant company is not required to complete the Form for Reporting Related Party Transactions, even where the related party transactions disclosed in its financial statements exceed S$15 million. A dormant company may file Form C-S, or the Form for Dormant Company instead.

A worked decision

A Singapore-incorporated design studio. Financial year ending 31 December 2026, revenue S$180,000, one trading activity, no incentives, no overseas withholding tax.

Step	Result
Incorporated in Singapore?	Yes
Revenue S$5m or below?	Yes — S$180,000
Only income taxed at 17%?	Yes
Claiming any of the four reliefs?	No
Qualifies for Form C-S	Yes
Revenue also S$200,000 or below?	Yes → Form C-S (Lite), 6 fields
Return due	30 November 2027 (YA 2027)
Financial statements submitted?	No — prepared and retained

Change one fact — the studio claims credit for tax withheld by an overseas client — and the same company files Form C, with financial statements, tax computation and supporting schedules attached. Nothing about its size changed.

Filing late, or filing the wrong form

Filing a simplified form you do not qualify for is not a shortcut. It gets queried and you file again, while 30 November stays where it is.

Missing the deadline is an offence. IRAS may:

• Issue an estimated Notice of Assessment, based on previous years' income or other available information — and when estimating, it may assume an increase in your income. The estimated tax is payable within one month, even if you object, and even while the objection is outstanding. Late payment penalties apply on top.
• Offer to compound the offence, for a composition amount of up to S$5,000 per offence, depending on your compliance history.
• Issue a notice to a director under s65B, requiring the return information from them personally.
• Issue a Notice to Attend Court to the company or to the people responsible for running it, directors included.

To object to an estimated assessment you must do so within two months of the Notice, and you must submit the return, financial statements and tax computation with the objection. Without those documents the estimated assessment is not revised — objecting on its own achieves nothing.

On conviction, a company may face a fine of up to S$5,000 for each offence. A director convicted of failing to comply with a s65B(3) notice faces a fine of up to S$10,000, imprisonment of up to 12 months, or both, for each offence. Where returns are outstanding for two years or more, the court may order a penalty of twice the amount of tax assessed, in addition to a fine of up to S$5,000. The statutory penalty for failure to make a return is at s94A.

A waiver of the composition amount can be appealed through myTax Portal, but IRAS considers it only where the outstanding returns were filed by the date given in the composition offer and the company filed on time for the previous two years. It is a concession for a first lapse, not a routine remedy.

An extension of time can be requested online for the current Year of Assessment, but only after 30 November, and not once a Notice to Attend Court has been issued. For earlier Years of Assessment no extension is granted at all.

Before you file

Check whether you needed to file ECI earlier in the year — a separate obligation, due three months after your financial year end. Confirm whether your company is exempt from audit, which changes what your financial statements must contain even where you do not submit them. Your own dates are in the deadline tracker.

Conditions and figures on this page follow IRAS guidance current at 27 January 2026. Thresholds change; check the IRAS page before relying on them for a filing.