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A Guide to Filing Corporate Taxes: Form C-S and Form C


In Singapore, it’s a common practice for a business to fill their returns to the Inland Revenue Authority of Singapore (IRAS) by filing the tax return forms C-S or C. Forms C-S or C must be duly completed and submitted within certain timeframes and it is important for a company to declare its annual income of companies.


What is Form C-S?

Introduced by the Singapore Government, Form C-S has simplified the filing process in terms of time and cost. Specifically speaking, Form C-S is an abridged 3-page income tax form that helps small companies to report their annual income to IRAS. This form can be submitted on paper or via e-filing.

a) Documents Needed for Filing of Form C-S

The documents needed for the submission of Form C-S are a declaration statement portraying the eligibility of the company and other essential tax and financial information only. Please note that the due date for e-filing is December 15 while paper Form C-S should be filed by 30 November. Documents like tax adjustments, tax computations, and financial accounts should be prepared and kept just in case the IRAS make a request to submit them.

b) What are the Criteria for Filing Form C-S?

  • The company should be incorporated in Singapore
  • An annual revenue of $5 million or less
  • Income derived taxable at 17%

However, you are not eligible to file tax returns if you claim:

  • Carry back of current year capital allowance/losses
  • Group relief
  • Investment allowance
  • Foreign tax credit or tax deducted at source

c) e-Filing of Tax Form C-S

  • E-filing of tax Form C-S is definitely easier as it increases productivity through technology and better public services. In addition, it helps in the auto-computation of payable tax. Taxpayers will receive instant acknowledgement once the tax is successfully filed. Just in case you have enquiries while filing tax forms, the iHelp will provide guidance when you need to clarify any doubts you have in mind. Please note that if your company is eligible to file for Form C-S, you can either e-file it or submit a hard copy after downloading it.
  • You should ensure that the company has an Access Code and that you’ve been authorised by the concerned company as an ‘Approver’ for ‘Corporate Tax Matters’ via e-Services Authorisation System (EASY) before e-filing form C-S. Also, please keep in hand the company’s tax reference number and personal SingPass or IRAS pin.


What is Form C?

Form C, on the other hand, is a 7-page form along with financial statements and tax computations along with others. If the company is not eligible to file form C-S, it should file Form C along with the afore-mentioned documents and other tax-relevant papers. Paper Form C should be submitted by 30 November and e-filing by 15 December.


How to Do e-Filing

  • Go to the website:
  • Select “Organisation/Business Tax Matters” and login using SingPass or IRAS PIN
  • Key in Organisation Tax Ref. No.
  • Click on “Corporate Tax” and select “File C-S/C”
  • Select the year of assessment (YA) for the year you are filing and continue to Form C-S
  • Go on to save the confirmation page and after saving, click “submit”.
  • Please note that you will log out automatically if you leave the filing page idle for more than 20 minutes. That said, you can always save the current session and continue later if you are unable to complete at one go. The draft that has been saved will remain in the portal up to 15 Dec, which is the last date for e-Filing.

Filing returns to IRAS could be tedious and time-consuming. Having said that, you can always reach out to 3E Singapore for professional assistance. Feel free to contact us today!

Related Link
Corporate Taxation Services
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