Annual Corporate Tax Return (Form C / C-S / C-S Lite)
The annual corporate income tax return must be filed with IRAS by 30 November of each Year of Assessment. The form type depends on company size and complexity: Form C-S Lite for revenue up to S$200k, C-S for revenue up to S$5m, and Form C for larger or more complex companies.
Who this applies to
- All Singapore-incorporated companies
- Singapore branches of foreign companies
- Form C-S Lite: companies with annual revenue up to S$200,000 that meet all C-S eligibility criteria
- Form C-S: companies with annual revenue up to S$5 million, Singapore-sourced income only, standard tax rate
- Form C: all other companies, including those with foreign income, special incentive rates, or revenue above S$5 million
What to file
Form C / C-S / C-S Lite as appropriate. For Form C, attachments include financial statements (audited or unaudited), tax computation, and capital allowance schedule. For C-S and C-S Lite, only the declaration and tax computation are submitted; financial statements are retained by the company.
How to file
File online via the IRAS myTax Portal. Paper filing is not accepted. Companies must use CorpPass to access the portal. Tax agents can file on behalf of companies. The filing must be completed by 30 November; no extensions are routinely granted.
Payment due
Tax is payable within 1 month of the date of the Notice of Assessment (NOA) issued by IRAS after processing the return. Companies that paid estimated tax via the instalment plan (following early ECI filing) will have any balance adjusted against the final NOA.
Penalties for missing this deadline
Late filing attracts composition fines. IRAS may also raise estimated assessments based on prior years with additional penalties. Persistent non-compliance can result in court summons. Interest at 5% per annum is levied on overdue tax.
Filing checklist
- Determine which form type applies (C-S Lite, C-S, or C)
- Finalise audited or unaudited financial statements for the financial year
- Prepare the full tax computation with all add-backs, deductions, and allowances
- Confirm eligibility for SUTE or Partial Tax Exemption and apply correctly
- File via myTax Portal by 30 November of the YA
- Retain supporting documents for at least 5 years
Documents you'll need
- Financial statements (audited if required; unaudited acceptable for qualifying small companies)
- Tax computation showing adjusted income, deductions, and exemptions
- Capital allowance schedule for all qualifying assets
- Directors' resolution approving financial statements
- Relevant disclosure forms if claiming special deductions or incentives
Common mistakes to avoid
- Filing Form C when the company qualifies for the simpler C-S or C-S Lite, creating unnecessary work
- Using an incorrect YA (remember that income earned in the financial year ending in 2024 is assessed in YA 2025)
- Failing to add back non-deductible expenses such as private car expenses or personal entertainment
- Omitting the S$2,000 minimum cash grant from the YA 2025 CIT Rebate scheme if the company employed at least one local worker in 2024
Never miss a Singapore deadline
AccountsOS tracks every Inland Revenue Authority of Singapore (IRAS) and Accounting and Corporate Regulatory Authority (ACRA) deadline and reminds you weeks ahead.
Try Free