Key corporate tax dates
Corporate tax should not be treated as one November deadline. The filing date matters, but the work starts when the financial year closes.
Use this table as a founder planning view, then check the latest IRAS guidance before filing.
| Item | Timing | Founder action |
|---|---|---|
| ECI review | Generally within 3 months after financial year end unless waiver or non-filing position applies | Close books early, review taxable profit, check waiver criteria, and confirm Corppass access |
| YA 2026 Corporate Income Tax Return | 30 Nov 2026 | Prepare Form C-S, Form C-S Lite, Form C, or dormant company filing as applicable |
| Director review | Before submission | Review accounts, tax computation, unusual transactions, and filing assumptions |
| Record retention | At least 5 years from the relevant YA | Keep source documents, bank statements, accounting records, and schedules retrievable |
What to prepare before filing
The return is the final submission. The real work is making sure the underlying accounts are complete enough to support the numbers.
For a startup, the practical preparation work should happen in stages rather than in the final weeks before filing.
- Final management accounts for the financial year
- Bank reconciliations for all operating, savings, card, and payment platform accounts
- Revenue schedule, customer invoices, and collection status
- Expense records, supporting documents, and fixed asset schedule
- Payroll, CPF, director fee, and contractor records where relevant
- Director/shareholder loan review and notes for unusual transfers
- Corppass authorisation for the person preparing or filing
Founder timeline for a December year end
If your company has a 31 December financial year end, work backward from ECI and the annual tax return. The aim is to avoid discovering missing records only when the filing deadline is close.
| Period | Focus | Outcome |
|---|---|---|
| January | Collect missing documents and close bookkeeping | Cleaner year-end records |
| February | Reconcile bank, cards, Stripe, Wise, and expense tools | Reliable trial balance |
| March | Assess ECI and waiver position | Earlier tax visibility |
| April to September | Resolve tax computation questions and director transactions | Fewer late surprises |
| October to November | Director review and filing checks | Ready before 30 Nov deadline |
Common filing mistakes
Most filing stress comes from stale bookkeeping rather than the tax form itself. If the accounts are not reconciled, the tax work becomes cleanup.
- Waiting until November to clean up the books
- Missing the ECI review because corporate tax is treated as one annual event
- Assuming a loss-making company has no filing responsibility
- Using unreconciled reports for tax computation work
- Finding out too late that Corppass access is not ready
This article is general information only and is not tax, legal, pricing, investment, or accounting advice. Check current official guidance and get professional advice for your company facts.