Corporate Income Tax Filing in Singapore: YA vs Financial Year, Deadlines and Who Files

The short answer. Singapore taxes companies on a preceding-year basis. Profits for a financial year that ends in 2025 are assessed in Year of Assessment (YA) 2026. Every company makes two filings for each YA: its Estimated Chargeable Income (ECI) within three months of its financial year end, and its Form C-S, Form C-S (Lite) or Form C by 30 November of the YA. The YA 2026 return is due on 30 November 2026.

Most late corporate tax filings we see in Singapore don’t come from carelessness. They come from one mix-up: reading “YA 2026” as “financial year 2026”. This guide walks through the who, what, when, where and how of filing corporate income tax, with the timing laid out so you can find your own dates at a glance.

What is the difference between YE and YA?

Three terms do all the work, and they are easy to blur:

• Financial year end (FYE or YE): the last day of the 12-month period your accounts cover. Your company chooses it. IRAS does not set it.
• Basis period: the financial year whose income is being taxed. For a company it is generally the 12 months ending on your FYE.
• Year of Assessment (YA): the year in which IRAS assesses and taxes that income. It is always the calendar year after the year in which your FYE falls.

So the rule of thumb is simple: take the calendar year your FYE falls in, and add one. The month does not matter. An FYE of 31 January 2026 and an FYE of 31 December 2026 both lead to YA 2027.

Notice that four very different year ends all land in YA 2027 and share the same 30 November 2027 deadline. A 31 March company has about 20 months between closing its books and filing its return; a 31 December company has 11.

Why do so many people get the timing wrong?

1. The YA names the tax year, not the earning year. “YA 2026” sounds like it should be about 2026. It is about income earned in a financial year that ended in 2025.
2. The two filings run on different clocks. ECI runs on your clock: three months from your FYE. Form C-S and Form C run on a fixed clock: 30 November every year. A company with a non-December year end can have its ECI and its tax return for the same YA more than a year apart.
3. ACRA and IRAS use different calendars. Your AGM and annual return are counted from the FYE (six and seven months). Your tax return is not. See our Singapore compliance calendar for how they fit together.
4. First-year accounts. A new company’s first financial period can be longer than 12 months, but a basis period cannot. If your first accounts run, say, from 15 July 2025 to 31 December 2026, the income is split across two YAs (YA 2026 and YA 2027). Choose your first FYE with this in mind.
5. Changing your FYE. If you change your year end on BizFile+, the new period may straddle two YAs and need two tax computations. IRAS updated its guidance on this in 2026.

Who has to file corporate income tax?

Every company that is incorporated or registered in Singapore, including Singapore branches of foreign companies. That includes companies that are dormant or loss-making: they must still file by 30 November unless IRAS has granted a waiver.

ECI is required unless your company qualifies for the waiver: annual revenue of S$5 million or below and ECI of nil for the YA. Both tests must be met.

Which return? It depends on your size and how simple your tax position is:

Who actually presses submit? The return is filed on the myTax Portal using Corppass, by an authorised person in the company or by an appointed tax agent. The directors remain responsible for it being correct and on time.

When is everything due? A year in the life of a 31 December company

How to file, step by step

1. Confirm your FYE and YA. Use the “add one” rule above, and check the FYE on your ACRA business profile.
2. Close the books. Prepare financial statements under the Singapore Financial Reporting Standards, audited if your company is not audit-exempt.
3. Prepare the tax computation. Adjust accounting profit for non-deductible expenses, capital allowances and exemptions to arrive at chargeable income.
4. File ECI on myTax Portal within three months of FYE, unless you qualify for the waiver.
5. File Form C-S, C-S (Lite) or C by 30 November of the YA. Keep the tax computation and supporting schedules even if your form does not ask you to submit them.
6. Pay on time. Tax is due one month from the Notice of Assessment. On GIRO, an ECI filed within one month of FYE can be paid in up to 10 instalments, within two months up to 8, and within three months up to 6. Filed later, no instalments.
7. Keep records for at least five years from the relevant YA.

What is different for YA 2026?

The headline rate stays at a flat 17%, with the partial tax exemption and the start-up tax exemption for new companies’ first three YAs. On top of that, YA 2026 brings a larger-than-planned rebate:

• Corporate income tax rebate of 50% of tax payable. Budget 2026 announced 40%, and the Government raised it to 50% on 7 April 2026.
• Cash grant of S$2,000 for active companies that employed at least one local employee in 2025.
• Combined cap of S$40,000 per company. No application is needed.

What happens if you file late?

• Estimated assessment: IRAS may issue an estimated Notice of Assessment based on past years or other information. You must pay it within one month, even if you disagree, and you need to file the actual return for it to be revised.
• Composition: IRAS may offer to compound the offence for a fee.
• Court: continued non-filing can lead to a summons for the company and the people running it.
• Late payment: a 5% penalty on unpaid tax, then a further 1% for each completed month the tax stays unpaid after 60 days, up to 12%.

If your YA 2026 return isn’t filed yet, file before 30 November 2026, even if the numbers need refining later. An on-time return is far cheaper to fix than an estimated assessment.

Frequently asked questions

Is the Year of Assessment the same as the financial year?

No. The financial year is the 12-month period your accounts cover. The Year of Assessment (YA) is the year in which IRAS taxes that income. Because Singapore taxes companies on a preceding-year basis, the YA is the calendar year after the year in which your financial year ends.

My financial year ends on 31 March 2026. Which YA is that?

YA 2027. Your Estimated Chargeable Income (ECI) is due by 30 June 2026, three months after year end, but your Form C-S or Form C is not due until 30 November 2027.

When is the YA 2026 corporate tax return due?

By 30 November 2026. YA 2026 covers financial years that ended in 2025, for example the year ended 31 December 2025 or 30 June 2025.

Does a dormant or loss-making company still need to file?

Yes. Every company must file its Form C-S, Form C-S (Lite) or Form C by 30 November, including companies that did not trade or made a loss, unless IRAS has granted a waiver to file.

Who qualifies for the ECI filing waiver?

A company whose annual revenue is S$5 million or below and whose ECI is nil for that YA. Both conditions must be met. Meeting only one means you still file.

What is the corporate income tax rebate for YA 2026?

A 50% rebate on tax payable, enhanced from the 40% first announced in Budget 2026. Active companies that employed at least one local employee in 2025 get a minimum S$2,000 as a cash grant. The combined benefit is capped at S$40,000 per company, and IRAS applies it automatically.

Need a hand? Ashlar prepares tax computations and files ECI and Form C-S/C for Singapore companies every week, including late and first-year filings. Message us on WhatsApp at +65 8876 5393 and a consultant will reply the same working day.

This guide is general information, current as at 12 November 2026. It is not legal or tax advice. Rules and fees change, so check the official source or speak to us before acting.

This article is general information about Singapore rules at the date of publication and is not legal or tax advice for your situation.