Documents Required for Corporate Tax Filing in Singapore: The Checklist for Form C-S, C-S (Lite) and Form C
The documents required for corporate tax filing in Singapore are the company's financial statements (audited or unaudited), a tax computation with its supporting schedules, and the records behind them. Form C-S and Form C-S (Lite) filers prepare and keep these, and send them only if IRAS asks. Form C filers upload them with the return, plus a detailed profit and loss statement, and complete the return's compulsory Additional Info page.
This checklist is for directors filing the Year of Assessment (YA) 2026 return, which covers the financial year ending in 2025. Amounts are in Singapore dollars, and the rules are as at November 2026.
Key takeaways
- The YA 2026 return is due 30 November 2026. Only Form C-S filed through accounting software is extended automatically, to 15 December.
- Form C-S and Form C-S (Lite): prepare the financial statements, tax computation and schedules before filing, keep them, and submit them only on IRAS's request.
- Form C: complete the compulsory Additional Info page of the online return (income and deduction details), and upload the financial statements and the tax computation with a detailed profit and loss statement as PDFs.
- Dormant company with Active status: file the Form for Dormant Company. IRAS does not need its financial statements.
- Keep records for at least 5 years from the YA. Without them, IRAS may estimate revenue and disallow claims.
Table of Contents
- What Documents Are Required for Corporate Tax Filing in Singapore?
- Which Return Does Your Company File?
- Documents to Prepare and Keep for Form C-S and C-S (Lite)
- What Must Be Filed With Form C?
- Extra Documents by Company Situation
- What Does My Accountant Need to File Form C-S?
- How Do You Authorise a Tax Agent in Corppass?
- Steps to File Your YA 2026 Return by 30 November
- What If Records Are Missing or You Miss 30 November?
- Common Mistakes and When to Get Help
- Frequently Asked Questions
- Official Sources
What Documents Are Required for Corporate Tax Filing in Singapore?
IRAS says a company must prepare its financial statements, tax computation and other supporting documents before it completes the return, whichever form it files. What differs between the forms is what you actually send.
A tax computation is the statement that adjusts the accounting profit to chargeable income: it adds back non-deductible expenses, removes non-taxable receipts, and applies further deductions and capital allowances (tax depreciation on fixed assets).
| Document | Form for Dormant Company | Form C-S or Form C-S (Lite) | Form C |
|---|---|---|---|
| Audited or unaudited financial statements | Not submitted to IRAS | Prepare, keep, send on request | File with the return |
| Tax computation and supporting schedules | IRAS does not list this | Prepare, keep, send on request | File with the return, even with no adjustments |
| Form IRIN 301 (Additional Information on Income and Deduction) | IRAS does not list this | Not required | On IRAS's list; income and deduction details go in the online return's Additional Info page, not in a separate upload |
| Detailed profit and loss statement | IRAS does not list this | Not required | File with the financial statements or tax computation |
| Research and development (R&D) Claim Form | IRAS does not list this | Prepare and keep, if claiming | File with the return, if claiming |
| Group Relief Forms GR-A and GR-B | IRAS does not list this | Group relief means Form C | Entered in the Group Relief section of the online Form C; no separate form submitted |
| Section 19B declaration (writing-down allowances on intellectual property rights) | IRAS does not list this | File with the return for the YA in which the rights were acquired (the first YA of the claim), plus any valuation report | File with the return for the YA in which the rights were acquired (the first YA of the claim), plus any valuation report |
| Revised tax computations for earlier YAs | IRAS does not list this | Loss carry-back means Form C | Only if claiming Loss Carry-Back Relief or reporting income missed in earlier years |
Which Return Does Your Company File?
Settle the form first, because it sets your document list. IRAS's conditions are:
- Form C-S (18 fields): incorporated in Singapore, annual revenue of $5 million or below, only income taxable at 17%, and not claiming carry-back of current-year capital allowances or losses, group relief, investment allowance, or foreign tax credit and tax deducted at source.
- Form C-S (Lite) (6 essential fields): meets the Form C-S conditions with annual revenue of $200,000 or below. Such a company may still choose Form C-S or Form C.
- Form C: everyone else, including companies incorporated outside Singapore and Singapore branches of foreign companies.
- Form for Dormant Company: Active status, no business and no income for the whole basis period.
Revenue here means the main income source, excluding separate source income such as interest. Our guide to corporate tax filing in Singapore covers the wider process, and our corporate tax form checker applies these tests.
Documents to Prepare and Keep for Form C-S and C-S (Lite)
IRAS's list for these two forms is: the audited or unaudited financial statements, the tax computation and supporting schedules, the section 19B declaration if the company claims writing-down allowances on intellectual property rights, and other supporting documents.
These are kept and sent on request, except the section 19B declaration, which goes in with the return for the YA in which the rights were acquired, through the Submit Document digital service. Where the intellectual property cost $10 million or more from a related party, or $40 million or more from an unrelated party, an independent valuation report also goes in with that return. "Unaudited" is in the list because dormant companies and companies that qualify as a small company under the Companies Act 1967 do not need an audit.
Form C-S takes its figures from the financial statements and the tax computation, as this map, based on IRAS's YA 2026 Explanatory Notes, shows:
| Form C-S item | Where the number comes from |
|---|---|
| Net profit or loss before tax | Profit and loss statement |
| Separate source income, non-taxable income, non-tax-deductible expenses, adjusted profit | Tax computation, with general ledger detail |
| Current-year capital allowances, balancing charges and allowances | Capital allowance schedule and fixed asset register |
| Unutilised capital allowances, losses and donations brought forward (pre-filled) | Last year's tax computation, Notice of Assessment and shareholder records |
| Current-year approved donations (pre-filled) | IRAS's View Donations digital service |
| Revenue, gross profit, directors' fees and remuneration, total remuneration excluding directors' fees, medical, transport and travelling, and entertainment expenses, inventories, trade receivables | Financial statements |
Non-tax-deductible expenses include depreciation, donations, fines and penalties, private expenses and S-plate car expenses, so your ledger needs to show them separately. And to carry forward unutilised capital allowances, losses or donations, at least 50% of the shareholdings must be held by the same shareholders on the relevant dates; for capital allowances the principal activities must also be unchanged. So keep the shareholder history.
What Must Be Filed With Form C?
A Form C company prepares a longer list, and IRAS says it is filed together with the return unless a document is specifically marked as kept for submission on request:
- Audited or unaudited financial statements.
- Tax computation and supporting schedules, even if there is no adjustment, with disallowable items shown as "Nil".
- Form IRIN 301 (Additional Information on Income and Deduction).
- A detailed profit and loss statement, with either the financial statements or the tax computation.
- Claim details such as group relief (entered in the Group Relief section of the online Form C, so no separate GR-A or GR-B form is needed) and the R&D Claim Form, where relevant.
- Revised tax computations for earlier YAs, only for Loss Carry-Back Relief or income not reported before.
- The section 19B declaration, if applicable, and other supporting documents.
Income and deduction details are declared on the compulsory Additional Info page of the online Form C. The PDFs uploaded through Submit Document are the financial statements, the tax computation and schedules (with the detailed profit and loss statement) and, where relevant, the section 19B declaration, R&D Claim Form and revised tax computations. The Form for Reporting Related Party Transactions is completed in the Related Party Transactions section of the online Form C, which opens when you answer Yes at item 31.
Attachments must be PDFs with a font size of at least 11 (IRAS suggests scanning at 100dpi black and white if you need smaller files), and the tax computation and its schedules must be merged into one PDF. Both the Preparer and the Approver can upload, but only the Approver can submit. If a full set of financial statements was filed with ACRA in XBRL format and shows as "Received (ACRA)" in Submit Document, you need not file the statements again, but the detailed profit and loss statement still goes in with the tax computation.
Larger companies have two more items. The Form for Reporting Related Party Transactions, part of Form C, is needed if related party transactions in the financial statements exceed $15 million. A company with related party transactions must prepare transfer pricing documentation under section 34F of the Income Tax Act 1947 if its trade or business revenue is above $10 million, or if documentation was required in the previous basis period, unless an exemption applies. It must be ready by the filing due date and is kept, not filed.
Extra Documents by Company Situation
The core pack is the same for everyone: financial statements, tax computation and schedules, and the source records behind them. Find your situations below and add their documents.
| Your situation | Extra documents to prepare and keep | Does it change the form? |
|---|---|---|
| Dormant, Active status, no income | None for IRAS | Form for Dormant Company. Fixed deposit interest or a donations claim means a regular return |
| Trading | Sales and purchase listings, general ledger, bank statements, stock list | Above $200,000 rules out Form C-S (Lite). Above $5 million generally means Form C |
| Claiming capital allowances | Fixed asset additions and disposals; capital allowance schedule per category (cost or tax written-down value brought forward, allowance, value carried forward); balancing charge or allowance on assets sold; hire purchase agreements | No |
| Renovation claim under section 14N | Itemised list of works and costs with premises addresses, confirming no Commissioner of Building Control approval was needed; invoices and payment details | No |
| Foreign dividends, branch profits or service income exempt under section 13(8) | Details in Part D of Form C's Additional Info page, or in the tax computation for Form C-S and Form C-S (Lite); evidence of foreign tax, such as the paying company's audited accounts showing current-year tax, or a bank certification or confirmation letter | No |
| Foreign tax credit claim | For each payment: country, nature of income, payer, gross amount, withholding tax rate and amount, and the withholding tax receipt or voucher | Yes, Form C |
| Directors' fees | Approval date and amount, any write-back or fees approved in arrears; AGM or EGM minutes | No |
| Company vehicles | Registration number of and amount for each vehicle | No |
| Rental income | Gross rent and direct expenses for each property, with the rental period | No |
| R&D further deduction | R&D Claim Form; project documentation kept from the start of the project | No |
Medical expenses are deductible up to 1% of total employees' remuneration. The cap rises to 2% if the company provides inpatient cover through a Portable Medical Benefits Scheme, a Transferable Medical Insurance Scheme or a Shield plan and meets that scheme's conditions, but the deduction above 1% excludes premiums for riders on Shield plans that cover deductibles and co-payments. Without one of those schemes, a company that makes ad-hoc MediSave contributions (deductible up to $2,730 per employee a year) can claim only those contributions above 1%, up to 2% in total; its other medical expenses stay capped at 1%. A company claiming more than 1% must declare in its tax computation that the conditions in sections 14(6A), (6B) and (6C) of the Income Tax Act 1947 are met.
Example, Company A, YA 2026:
- Total employee remuneration: $200,000
- 1% of remuneration: $2,000
- 2% of remuneration: $4,000
- Medical expenses claimed: $3,500
- Result: $3,500 is above the 1% cap of $2,000 but within the 2% cap of $4,000. The full $3,500 is deductible only if the company meets the 2% conditions and makes the declaration in the tax computation. Otherwise only $2,000 is deductible.
IRAS's non-exhaustive "Other Documents" list adds items such as an exchange gain and loss breakdown, bad debt details, sales and purchases of property and shares, and section 13W share gains.
What Does My Accountant Need to File Form C-S?
IRAS's list says what the company must prepare, not what to hand over. When a company asks us to file, these are the six items we ask for. This is our own practice and goes beyond IRAS's list:
- Financial statements, signed or draft, or if there are none yet, a trial balance and general ledger.
- Bank statements for the whole financial year.
- Last year's tax computation.
- The latest Notice of Assessment.
- Fixed asset additions and disposals for the year.
- Corppass authorisation for our firm.
The prior-year tax computation and Notice of Assessment matter because IRAS pre-fills the brought-forward capital allowances, losses and donations. If your records differ, you can update those amounts in the "Company's Declaration" field, but you need the papers to show which figure is right.
Add, if they apply: directors' fee approvals and AGM minutes, foreign or rental income details, renovation invoices, and any change in shareholders during the year.
If the books are not closed, the bottleneck is the financial statements, not the return. Our financial statements service covers that step.
How Do You Authorise a Tax Agent in Corppass?
Employees and third parties, including tax agents, must be authorised through Corppass before they can use IRAS digital services for a company. To complete and submit Form C-S or Form C-S (Lite), they need the Approver role for Corporate Tax (Filing and Applications). A Preparer can only complete the form for an Approver to submit.
Based on IRAS's Corppass FAQ and step-by-step guides for tax agents and companies:
- The company sets up its Corppass Administrator account, if it has not already.
- The Administrator selects Corporate Tax (Filing and Applications) among the company's IRAS e-Services, if not already done, then authorises the tax agent firm for it through "Authorise Third Party Entities", with both the Preparer and Approver roles.
- The firm assigns the company's e-Services to its own staff.
IRAS says directors are responsible for timely and accurate filing even when a tax agent has been engaged.
Steps to File Your YA 2026 Return by 30 November
- Check the company's filing status. "No Business Done" means a waiver and nothing to file for YA 2026. A dormant company with "Active" status files the Form for Dormant Company.
- Pick the return: Form C-S (Lite), Form C-S or Form C.
- Close the accounts for the financial year ending in 2025 and finalise the financial statements.
- Prepare the tax computation and schedules, with fixed asset and capital allowance schedules if relevant.
- Authorise the filer in Corppass as Approver. The filer also needs Singpass and the company's UEN.
- Check the pre-filled figures: brought-forward amounts against your records, and current-year approved donations against View Donations.
- File by 30 November 2026. Form C filers upload the PDFs. A draft stays in myTax Portal for 21 days or until 30 November, whichever is later. The acknowledgement page appears as soon as you file, so save or print it then; a copy can take up to 3 working days to appear in View Corporate Tax Notices/ Letters. Do not send it to IRAS.
- Keep everything for at least 5 years from the YA.
What If Records Are Missing or You Miss 30 November?
IRAS requires companies to keep records for at least 5 years from the relevant YA: source documents such as invoices, receipts and vouchers, accounting records and schedules, and bank statements, on paper or electronically. IRAS's example is that YA 2023 records (financial year ended 30 September 2022) are kept until 31 December 2027. On the same pattern, YA 2026 records are kept until at least 31 December 2030.
Failing to keep records is an offence, with a penalty of up to $5,000 and up to 6 months' imprisonment if it is not paid. Our backlog accounting service rebuilds missing years.
If the return is not filed by 30 November 2026, IRAS may:
- Issue an estimated Notice of Assessment, payable within 1 month even if you object. To revise it, you must object within 2 months and submit the return, financial statements and tax computation.
- Offer to compound the offence for up to $5,000 per offence.
- Send a director a section 65B(3) notice. A director convicted of not complying faces a fine of up to $10,000, imprisonment of up to 12 months, or both, per offence.
- For two or more years not filed, take the company to court, where the penalty is twice the tax assessed plus a fine of up to $5,000 per offence.
An extension for the current YA can be requested online only after 30 November. None is given for earlier years, or once a Notice to Attend Court has been issued. Our guide to the IRAS estimated Notice of Assessment covers the objection process.
Common Mistakes and When to Get Help
- Treating "not submitted" as "not needed". A Form C-S filer with no tax computation has nothing to show IRAS if asked.
- Counting interest in the revenue test. Separate source income is left out, except for investment holding companies.
- Accepting pre-filled brought-forward figures without checking last year's computation and Notice of Assessment.
You may not need help. A dormant company can file the Form for Dormant Company itself, and a small trading company with clean books can often file Form C-S (Lite) using IRAS's Basic Corporate Income Tax Calculator.
Get help when the accounts are not closed, when there are fixed assets, foreign income or losses to carry forward, when you file Form C, or when 30 November is close and you do not know what is missing. If you prepare the tax computation yourself, our guide to deductible expenses for SMEs helps with the adjustments.
Frequently Asked Questions
Is a tax computation needed if the company made a loss?
Yes. A company must file a return even if it made a loss, and IRAS expects a tax computation to be prepared every year before the return is completed. For a loss-making company the computation also fixes the unutilised losses and capital allowances carried forward. A Form C filer must submit the computation even when there is no adjustment, showing disallowable items as Nil.
Does a dormant company need to send financial statements to IRAS?
No. A dormant company whose status is Active files the Form for Dormant Company, which has two essential fields and takes about 5 minutes, and IRAS says its financial statements need not be submitted. A company that earned fixed deposit interest is not dormant for that year, and a dormant company that wants to claim donations files Form C-S, Form C-S (Lite) or Form C instead of the Form for Dormant Company.
What is Form IRIN 301?
Form IRIN 301, Additional Information on Income and Deduction, is on IRAS's list of documents a Form C company prepares. In the online Form C, income and deduction details are declared on the compulsory Additional Info page, for example Part A, Deductions Claimed Against Income, and IRIN 301 is not one of the Submit Document upload categories. Form C-S and Form C-S (Lite) filers do not need it. It is separate from the Form for Reporting Related Party Transactions.
Can I file if my financial statements are not finished?
No. Our position is to finish at least unaudited financial statements before filing. IRAS expects them to be prepared before you complete the return, and the Form C-S figures come from them. Unaudited statements are fine if the company is exempt from audit, and we can work from draft statements or a trial balance to get there. The ACRA annual return also needs financial statements approved by the directors, so they must be finished anyway.
Do I need to attach receipts or invoices to Form C-S?
No. Form C-S and Form C-S (Lite) are filed without attachments. The exception is the first year of a claim for writing-down allowances on intellectual property rights: the company then submits the section 19B declaration through Submit Document and, for very large acquisitions, an independent valuation report. Invoices, receipts, bank statements and the general ledger are kept for at least 5 years from the Year of Assessment and produced only if IRAS asks for them. Without them, IRAS may estimate revenue and disallow claims.
Does IRAS need audited financial statements?
No. IRAS accepts audited or unaudited financial statements, whether they are filed with Form C or kept for a Form C-S or Form C-S (Lite) return. Whether the accounts must be audited is a Companies Act 1967 question, not an IRAS one: dormant companies and companies that qualify as a small company are exempt from audit, and their unaudited statements are enough for Form C-S, Form C-S (Lite) or Form C.
Official Sources
- IRAS: Guidance on filing Form C-S, Form C-S (Lite) and Form C (documents to prepare)
- IRAS: Corporate Income Tax Filing Season 2026
- IRAS: Overview of Form C-S, Form C-S (Lite) and Form C
- IRAS: Preparing a tax computation
- IRAS: Using accounting software to file Form C-S (15-day extension)
- IRAS: Record keeping requirements
- IRAS: Dormant companies
- IRAS: Late filing or non-filing of Corporate Income Tax Returns
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Last updated: 9 November 2026. This article is general information based on IRAS and ACRA guidance as at November 2026, not advice for your specific situation. Rules, rates and deadlines change, so check the official sources above or speak to us before acting.