Understanding Your Corporate Tax Filing Obligations in Singapore: Key Facts About Form C-S and Form C

Every company in Singapore—whether actively trading or dormant—is required to file an annual Corporate Income Tax Return with the Inland Revenue Authority of Singapore (IRAS). Filing your tax return on time is a legal obligation, and failure to comply may result in penalties, enforcement action, or unnecessary tax exposure.

This article explains what businesses need to know about the Form C-S/ Form C filing process, including key deadlines, filing methods, and how to stay compliant.

What Is the Corporate Income Tax Filing Deadline?

For all Year of Assessment (YA) 2025 filings (covering your company’s financial year ending in 2024), the deadline to file Form C-S or Form C is: 30 November 2025

All companies must file their Corporate Income Tax Return by this date, regardless of whether the company made a profit, loss, or remained dormant.

Form C-S vs Form C: What’s the Difference?

The type of form your company must file depends on its size and eligibility:

Form C-S (Simplified)

Most small to medium-sized companies qualify to file this simplified version if they meet all the following:

• Incorporated in Singapore

• Annual revenue is $5 million or less

• Derives only income taxable at the prevailing corporate tax rate

• Not claiming carry-back of losses, group relief, investment allowance, etc.

Form C (Full version)

Used by companies that:

• Have revenue exceeding $5 million

• Derive income from sources subject to special tax treatment

• Are claiming complex tax reliefs

Form C requires submission of financial statements, detailed tax computations, and supporting schedules.

What About Form C-S (Lite)?

If your company’s annual revenue is $200,000 or less, you may qualify to use Form C-S (Lite), a simplified version of Form C-S that requires fewer input fields and no financial statements.

This further streamlines filing for micro-SMEs.

Key Requirements for Filing

Regardless of form type, companies are required to:

• Maintain proper accounting records

• Prepare financial statements in accordance with Singapore Financial Reporting Standards (SFRS)

• Complete tax computations (except Form C-S Lite)

• File electronically via myTax Portal (e-filing is compulsory)

Consequences of Late or Non-Filing

Missing the 30 November deadline can result in:

• Late filing penalties

• Estimated assessments issued by IRAS (which may not reflect your actual income)

• Prosecution for non-compliance

It’s critical to prepare early and engage a professional if needed.

Let Us Help You Stay Compliant

Our team provides end-to-end support for Singapore companies to meet their annual tax obligations, including:

• Preparing and filing Form C-S or C

• Financial statement preparation

• Tax computation and adjustments

• Cloud accounting and record-keeping support

• Corporate tax advisory and planning

Whether you're a startup, growing SME, or dormant company, we ensure that your corporate tax matters are handled accurately and on time.

Plan Ahead for a Stress-Free Filing Season

The annual corporate tax filing deadline may feel far off, but early preparation saves you time, avoids penalties, and allows room for proper tax planning. With our support, you’ll have peace of mind that your business is in full compliance with IRAS requirements.

Contact us today to get started on your tax filing for YA 2025.

Disclaimer: This article is intended for general guidance and is accurate at the time of publication. For the latest information or advice tailored to your business, please refer to IRAS or consult a qualified tax professional.