When and what must be filed for Singapore corporate income tax?

Generally, Estimated Chargeable Income (ECI) is filed within 3 months after the end of the financial year, and the corporate income tax return (Form C-S, Form C-S (Lite) or Form C) is filed by 30 November every year.

ECI is the estimated chargeable income for the relevant Year of Assessment. ECI filing may be waived if annual revenue is S$5,000,000 or less and the ECI is nil. Even with no revenue or a loss, the corporate income tax return generally must be filed; exceptions may include dormant companies granted a filing waiver by IRAS.

• For the first financial year: the timing of the first filing depends on the financial year end and the Year of Assessment (YA), so please check in advance after incorporation.
• If Form C-S is filed through accounting software: IRAS has a scheme that automatically extends the deadline by 15 days (from 30 November to 15 December), and the applicable Year of Assessment should be confirmed in IRAS guidance.

Tax treatment can differ depending on the company's revenue, shareholder structure and transactions, so please consult an accounting professional before applying it.

The Lee Kim Alliance accounting team provides accounting and tax consultations.

As of November 2026, source: IRAS, IRAS