YA 2026 Corporate Tax Filing Checklist: Form C-S, Form C-S (Lite) or Form C?

YA 2026 Filing Deadline

Singapore companies generally must file their Year of Assessment 2026 Corporate Income Tax Return by 30 November 2026 through myTax Portal, unless IRAS has granted a filing waiver.

The filing requirement can still apply where a company made a loss or had no income. For a company with a 31 December year end, YA 2026 generally relates to the financial year ended 31 December 2025.

Directors remain responsible for timely and accurate filing even when a tax agent is appointed. IRAS states that late filing or non-filing may result in enforcement action and penalties of up to S$5,000.

Which Corporate Tax Form Should Your Company Use?

Form C-S (Lite)

Form C-S (Lite) may be used when the company:

• Is incorporated in Singapore.
• Has annual revenue of S$200,000 or below.
• Meets all the qualifying conditions for Form C-S.

It is intended for companies with straightforward tax matters and requires only six essential fields. The company does not submit its financial statements and tax computation with the return, but must prepare and retain them for submission if IRAS requests them.

Form C-S

A company may file Form C-S when it:

• Is incorporated in Singapore.
• Has annual revenue of S$5 million or below.
• Derives only income taxable at the prevailing corporate income tax rate of 17%.
• Is not claiming current-year loss or capital-allowance carry-back, group relief, investment allowance, foreign tax credit or tax deducted at source.

Qualifying companies do not submit their financial statements and tax computation with Form C-S, but these documents must still be prepared and retained.

Form C

Form C must be used if the company does not qualify for Form C-S, Form C-S (Lite) or the Form for Dormant Company.

Financial statements, tax computation, supporting schedules and other applicable documents must generally be filed together with Form C. A company filing a full set of financial statements with ACRA in XBRL format should check the applicable IRAS submission requirements.

Form for Dormant Company

For YA 2026, a company that did not carry on business and had no income during the relevant financial year may use the Form for Dormant Company. IRAS describes this as a simplified return containing two essential declarations.

A dormant company must still file unless IRAS has granted a waiver. Dormant status for tax filing should be assessed carefully where the company received interest, rent, dividends or other income.

Documents to Prepare Before Filing

• Audited or unaudited financial statements, as applicable.
• A tax computation reconciling accounting profit or loss to taxable income.
• Schedules for non-deductible expenses, capital allowances and balancing adjustments.
• Records of unutilised losses, capital allowances and donations brought forward.
• Details of related-party transactions and applicable supporting documents.
• Claim forms or declarations for incentives, group relief, research and development or intellectual-property allowances, where applicable.
• Corppass authorisation for the person preparing, approving or submitting the return.

A Quick Form-Selection Check

1. Was the company dormant with no income? Consider the Form for Dormant Company.
2. Is it Singapore-incorporated and is annual revenue S$200,000 or below? Check whether all Form C-S conditions are met before selecting Form C-S (Lite).
3. Is it Singapore-incorporated, is annual revenue S$5 million or below and are all other Form C-S conditions met? Consider Form C-S.
4. If none of the above applies, use Form C.

Choosing the shortest form is not the objective. The company should use the form that correctly reflects its facts, income and claims.

Do Not Confuse the Annual Return with ECI

The YA 2026 Corporate Income Tax Return is separate from the Estimated Chargeable Income filing. ECI is generally due within three months after the company's financial year end unless an exemption applies. Filing one obligation does not replace the other.

Common Filing Mistakes

• Selecting Form C-S based only on revenue and overlooking the other qualifying conditions.
• Treating a company as dormant even though it earned interest or other income.
• Filing before the financial statements and tax computation are complete.
• Omitting tax adjustments for non-deductible expenses or capital items.
• Failing to reconcile brought-forward losses and capital allowances to earlier tax assessments.
• Leaving Corppass authorisation until the filing deadline.

How LN Corporate Services Can Help

LN Corporate Services can assist with tax computations, deductible-expense reviews, capital-allowance schedules and filing of Form C-S, Form C-S (Lite) or Form C. Where statutory audit is required, LN CO Assurance can separately discuss the audit engagement, subject to professional and independence requirements.