Companies operating in Singapore must comply with several corporate income tax deadlines. The two main filing obligations are the Estimated Chargeable Income (ECI) and the annual Corporate Income Tax Return, filed through Form C-S, Form C-S (Lite), Form C, or the applicable dormant company form.
For Year of Assessment (YA) 2026, companies must file their Corporate Income Tax Return by 30 November 2026. The ECI deadline depends on the company’s financial year-end and generally falls within three months after that date.
SGA’s tax compliance services help companies calculate taxable income, prepare supporting documents, and submit returns accurately.
Quick Answer: What Are the Corporate Tax Deadlines for 2026?
Tax Obligation | 2026 Deadline |
| Estimated Chargeable Income | Within three months after the financial year-end |
Form C-S, Form C-S (Lite), Form C, or applicable company return | 30 November 2026 |
| Corporate tax payment | Within one month from the Notice of Assessment unless otherwise stated |
These deadlines should be recorded in the company’s financial calendar. Directors remain responsible for accurate and timely filing, even when an external tax agent has been appointed.
Estimated Chargeable Income Filing Deadline
ECI is an estimate of a company’s taxable profits for a Year of Assessment. A company must generally file its ECI within three months from the end of its financial year. For example:
- Financial year ending 31 December 2025: ECI due by 31 March 2026
- Financial year ending 31 March 2026: ECI due by 30 June 2026
- Financial year ending 30 June 2026: ECI due by 30 September 2026
A company may qualify for an ECI filing waiver when annual revenue is S$5 million or below, and ECI is nil. Both conditions must be satisfied.
Corporate Income Tax Return Deadline
All companies required to file their YA 2026 Corporate Income Tax Return must submit it electronically through the IRAS myTax Portal by 30 November 2026. This requirement applies even when a company:
- Made a financial loss
- Had no taxable profit
- Did not conduct business for part of the year
- Is awaiting review of a previous tax assessment
A dormant company may still need to file the applicable return unless IRAS has granted a filing waiver.
SGA’s accountants in Singapore determine which return applies. Form C-S is available to qualifying Singapore-incorporated companies with annual revenue of S$5 million or below. Form C-S (Lite) may be used by qualifying companies with annual revenue of S$200,000 or below. Companies that do not meet simplified filing conditions generally use Form C.
Documents Required for Corporate Tax Filing
Businesses should prepare tax documents well before the deadline. Depending on the applicable form, these may include:
- Financial statements
- Detailed profit and loss accounts
- Tax computations
- Fixed asset schedules
- Capital allowance calculations
- Supporting schedules for deductible expenses
- Details of non-taxable income
- Records of donations and tax incentives
Reliable financial reporting is essential, as accounting profit must be adjusted to calculate chargeable income. Non-deductible expenses, capital allowances and non-taxable receipts can affect the final calculation.
SGA’s Singapore Accounting Service reconciles accounting records and prepares the necessary schedules before filing begins.
How to Prepare for the 2026 Deadlines
- Close the books and reconcile bank, receivable, and payable balances promptly.
- Finalise financial statements and identify relevant tax adjustments.
- Assess ECI requirements and confirm whether an ECI waiver applies.
- Determine the appropriate Corporate Income Tax Return form.
- Review supporting documentation before electronic submission.
What Happens If a Company Files Late?
Late or non-filing can result in enforcement action. IRAS may issue an estimated assessment, impose penalties, or take further action against the company and its directors. Late filing of the annual Corporate Income Tax Return may result in penalties of up to S$5,000.
An estimated assessment must not be ignored. The company may still need to submit its outstanding return and address the assessment through the appropriate IRAS process.
Dependable accounting services in Singapore help businesses maintain accurate records, monitor deadlines, and reduce the risk of preventable filing errors.
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The most important corporate tax dates for 2026 are the ECI deadline, generally within three months after the financial year-end, and the 30 November 2026 deadline for the YA 2026 Corporate Income Tax Return.
Companies should finalise their accounts early, prepare accurate tax computations, and confirm which filing form applies. SGA’s accountants and tax compliance specialists help businesses meet these responsibilities, allowing management to focus on daily operations and long-term growth.